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排序方式: 共有587条查询结果,搜索用时 15 毫秒
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2.
Lead is a heavy metal widely distributed in the environment. Lead is a ubiquitous environmental toxin that is capable of causing numerous acute and chronic illnesses. Human and animal exposure demonstrates that lead is nephrotoxic. However, attempts to reduce lead-induced nephrotoxicity were not found suitable for clinical use. Recently, flaxseed oil (FXO), a rich source of ω-3 fatty acids and lignans, has been shown to prevent/reduce the progression of certain types of cardiovascular and renal disorders. In view of this, the present study investigates the protective effect of FXO on lead acetate (PbAc)-induced renal damage. Rats were pre-fed normal diet and the diet rich in FXO for 14 days, and then, four doses of lead acetate (25 mg/kg body weight) were administered intraperitoneally while still on diet. Various serum parameters, enzymes of carbohydrate metabolism, brush border membrane (BBM), and oxidative stress were analyzed in rat kidney. PbAc nephrotoxicity was characterized by increased serum creatinine and blood urea nitrogen. PbAc increased the activities of lactate dehydrogenase and NADP-malic enzyme, whereas it decreased malate and glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, fructose-1, 6-bisphosphatase, and BBM enzyme activities. PbAc caused oxidant/antioxidant imbalances as reflected by increased lipid peroxidation and decreased activities of superoxide dismutase, glutathione peroxidase, and catalase. In contrast, FXO alone enhanced the enzyme activities of carbohydrate metabolism, BBM, and antioxidant defense system. FXO feeding to PbAc-treated rats markedly enhanced resistance to PbAc-elicited deleterious effects. In conclusion, dietary FXO supplementation ameliorated PbAc-induced specific metabolic alterations and oxidative damage by empowering antioxidant defense mechanism and improving BBM integrity and energy metabolism. 相似文献
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4.
J H Romaldini C S Farah R S Werner R P Dall'Antonia Júnior R S Camargo 《Hormones et métabolisme》1988,20(8):510-512
The TSH effect on slice and the incubation medium cyclic AMP levels and T3 and T4 released from 8 autonomously functioning thyroid nodules (AFTN) and their respective perinodular (PN) tissues were examined. The thyroid slices were incubated in Eagle's Medium containing TSH (5 to 100 mU/ml) for 60 min and 300 min for tissue cyclic AMP generation and for cyclic AMP, T3 and T4 release, respectively. Basal cyclic AMP levels were not different either in AFTN and in PN slices or into the incubation medium. In both tissues TSH produced a similar cyclic AMP generation. In contrast, cyclic AMP released into the incubation medium was significantly higher in AFTN than in PN tissues, after TSH stimulation. Basal T3 values and TSH-stimulated T3 release in AFTN were not different from PN tissue. However, basal T4 levels were significantly higher in AFTN than in PN tissue as well as T4 released in response to TSH. In addition, T3/T4 ratio was lower in AFTN than in PN tissues. The cyclic AMP released into the incubation medium correlated with both T3 and T4 release in PN tissue but in the AFTN tissue no correlations were found. These findings suggest that the adenylate cyclase-cyclic AMP system is more sensitive to TSH-stimulation in AFTN when compared with PN tissue and that AFTN tissue has a preferential T4 secretion. 相似文献
5.
Glucocorticoid inhibition of immunoreactive beta-endorphin release from the anterior lobe of the rat pituitary: in vitro and in vivo studies 总被引:1,自引:0,他引:1
G P Mueller D J Pettibone J M Farah D Sapun-Malcolm 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1985,179(3):338-347
Glucocorticoid control of pituitary beta-endorphin (beta-END) release was investigated in vitro and in vivo. Cultured cells of both rat anterior (AL) and neurointermediate (NIL) lobe released beta-END-like immunoreactivity (beta-END-LI) in response to epinephrine (10(-7) M); however, only the response of AL cells was prevented by corticosterone (10(-8)-10(-6) M) or dexamethasone (10(-9)-10(-7) M). Gel chromatographic analysis (Sephadex G-50) revealed that the major forms of beta-END-LI released by AL cells corresponded to beta-END and beta-lipotropin (beta-LPH) in molecular size, whereas virtually all of the immunoreactivity released by NIL cells resembled beta-END. In vivo administration of dexamethasone attenuated the stress-induced release of beta-END-LI in a dose- and time-related fashion, having a more pronounced effect on plasma levels of beta-END-LI corresponding to beta-LPH in molecular size. Metyrapone (100 mg/kg), an inhibitor of glucocorticoid synthesis, evoked a rapid (20-40 min) four- to sixfold increase in total plasma beta-END-LI and 75% of this rise was due to immunoreactivity resembling beta-LPH in size. This response was diminished by coadministration of either dexamethasone (0.05-1.25 mg/kg) or corticosterone (0.05-1.25 mg/kg) and completely prevented by 4-hr pretreatment with dexamethasone (50 micrograms/kg). The briskness of the plasma beta-END-LI response to acute changes in glucocorticoid status suggests that a "rapid" feedback mechanism operates in the physiologic control of pituitary beta-END-LI secretion. Moreover, the ability of glucocorticoids to selectively inhibit AL release of beta-END-LI in vitro and their pronounced effect on plasma levels of beta-END-LI resembling beta-LPH, a marker of AL secretion, together indicate that glucocorticoids exert a selective influence over the secretion of AL corticotrophs in vivo. This demonstration of differential regulation of the AL versus IL secretion of beta-END-LI in vivo most likely reflects a phenomena having biologic importance related to the different physiologic actions of the several molecular forms of beta-END-LI secreted by the two tissues. 相似文献
6.
S B Farah D C Gruenert J A Lepercq J Chueh A Metzger E L Sartorato R V Lebo M S Golbus 《Biochemical and biophysical research communications》1992,189(1):581-589
A sorted, cloned Y chromosome phage library was screened for unique Y chromosome sequences. Of the thousands of plaques screened, 13 did not hybridize to radiolabeled 46,XX total chromosomal DNA. Three plaques were characterized further. Clone Y1 hybridized to multiple restriction enzyme fragments in both male and female DNA with more intense bands in male DNA. Clone Y2, also found in female and male DNA, is probably located in the pseudosutosomal region because extra copies of either the X or Y chromosomes increased Y2 restriction enzyme fragment intensity in total cellular DNA. Clone Y5 was male specific in three of four restriction enzyme digests although in the fourth a light hybridizing band was observed in both male and female DNA. Clone Y5 was sublocalized to band Yq 11.22 by hybridization to a panel of cellular DNA from patients with Y chromosome rearrangements. Clone Y5 can be used to test for retention of the proximally long arm Y suggested to cause gonadal cancer in carrier females. The long series of GA repeats in Y5, anticipated to be polymorphic, may provide a sensitive means to follow Y chromosome variation in human populations. 相似文献
7.
Martina Ferraguti Sergio Magallanes Jéssica Jiménez-Peñuela Josué Martínez-de la Puente Luz Garcia-Longoria Jordi Figuerola Jaime Muriel Tamer Albayrak Staffan Bensch Camille Bonneaud Rohan H. Clarke Gábor Á. Czirják Dimitar Dimitrov Kathya Espinoza John G. Ewen Farah Ishtiaq Wendy Flores-Saavedra László Zsolt Garamszegi Olof Hellgren Dita Horakova Kathryn P. Huyvaert Henrik Jensen Asta Križanauskienė Marcos R. Lima Charlene Lujan-Vega Eyðfinn Magnussen Lynn B. Martin Kevin D. Matson Anders Pape Møller Pavel Munclinger Vaidas Palinauskas Péter L. Pap Javier Pérez-Tris Swen C. Renner Robert Ricklefs Sergio Scebba Ravinder N. M. Sehgal Manuel Soler Eszter Szöllősi Gediminas Valkiūnas Helena Westerdahl Pavel Zehtindjiev Alfonso Marzal 《Global Ecology and Biogeography》2023,32(5):809-823
Aim
The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations.Location
Global.Time period
2002–2019.Major taxa studied
Avian Plasmodium parasites in house sparrows.Methods
We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests.Results
Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected.Main conclusions
Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows. 相似文献8.
C E Negrao E D Moreira M C Santos V M Farah E M Krieger 《Journal of applied physiology》1992,72(5):1749-1753
The present investigation was undertaken to evaluate the vagal function of trained (T) and sedentary (S) rats by use of different approaches in the same animal. After 13 wk of exercise training (treadmill for 1 h 5 times/wk at 26.8 m/min and 15% grade), T rats had a resting heart rate (HR) slightly but significantly lower than S rats (299 +/- 3 vs. 308 +/- 3 beats/min). T rats had marked reduction of the intrinsic HR (329 +/- 4 vs. 369 +/- 5 beats/min) after blockade by methylatropine and propranolol. They also exhibited depressed vagal and sympathetic tonus. Baroreflex bradycardia (phenylephrine injections) was reduced, bradycardic responses produced by electrical stimulation of the vagus were depressed, and responses to methacholine injection were decreased in T rats. Therefore several evidences of vagal function impairment were observed in T rats. The resting bradycardia after exercise training is more likely to be dependent on alterations of the pacemaker cells, inasmuch as the intrinsic HR was markedly reduced. 相似文献
9.
Farah MG 《Cardiovascular diseases》1979,6(4):447-452
First heart sound alternans in the absence of pulsus alternans, or variation in heart rate (i.e., variation in PR interval), occurring in a patient with massive neoplastic pericardial effusion is described. The mechanism appears to be similar to that in electrical alternans and is shown by echocardiography to be related to the cardiac position within the pericardium, with the first heart sound intensity varying according to the distance of the heart from the chest wall. First heart sound alternans, electrical alternans, and alternating cardiac motion within the pericardium disappeared following pericardiocentesis. 相似文献
10.
Farah T. van Genderen Frans K. Gorus Ilse Vermeulen Evilien M.F. Vekens Pieter E.M. De Pauw Daniel G. Pipeleers Chris Van Schravendijk 《Analytical biochemistry》2010,404(1):8-13
We present a time-resolved fluorescence immunoassay (TR-FIA) for the measurement of rat insulin in cell extracts and culture media. This assay is based on the binding of two monoclonal antibodies to different parts of the insulin molecule in a 96-well microtiter plate. For the detection, europium-labeled streptavidin that interacts with the second biotinylated antibody is used. Samples of 25 μl could be analyzed in less than 2 days with a measuring range between 5 and 1250 pg (0.2-50 μg/L or 34.4-8600 pM). The inter- and intraassay percentage coefficients of variation were less than 8.3 and 5.1, respectively. Recoveries of 0.48 to 40 μg/L rat insulin, added to culture medium, ranged between 94 and 107%. Results were significantly correlated with those of an in-house radioimmunoassay (RIA) for rodent insulin (P < 0.0001, r2 = 0.99). The TR-FIA method had a similar detection limit (0.16 μg/L), but its working range was at least 5-fold larger. Additional advantages include the lower cost, the applicability to measurements in tissue and serum, and the quantification of insulin from other species. 相似文献