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匹配条件: “M Ebrahimi” ,找到相关结果约400700条。
Effects of in vivo and in vitro Zinc and Cadmium Treatment on Sperm Steroidogenesis of the African Catfish Clarias gairepinus
M. Ebrahimi
Pakistan Journal of Biological Sciences , 2007,
Abstract: The aim of present research to study the effects of in vitro and in vivo exposure of catfish to heavy metals to determine whether the steroidogenic activity in sperm would be affected by two heavy metals contaminants, zinc and cadmium. Three groups of six male African catfish were fed from the sexually immature juvenile stage, with diet containing 1000 ppm zinc, cadmium or zinc + cadmium for 110 days and 20αHSD activity in milt of these fish were compared with six other control fish fed with normal diet. The 20αHSD enzyme activity was also measured in in vitro incubation of milt from six control fish with different concentrations (0, 0.1, 1, 3, 10, 30, 100, 1000 and 3000 ppm) of zinc, cadmium or zinc + cadmium. A very high 20α hydroxy steroid dehydrogenase enzyme activity was found in all sperm incubations of African catfish. This enzyme converts 17-hydroxy progesterone (17P) substrate to 17,20α-dihydroxy progesterone (17, 20αP) product and the rate of enzyme activity is related to substrate (17P) concentrations. Significant differences (p<0.05) in enzyme activity in converting 17P to 17,20αP were found between in vitro incubations of sperm with different concentrations of zinc, cadmium or zinc + cadmium and control group (0 ppm). Significant differences (p<0.05) in enzyme activity and 17,20αP production were found between fish fed with diet containing 1000 ppm zinc or cadmium and the group fed with diet containing 1000 ppm zinc + cadmium and control groups. The results showed that 20αHSD enzyme activities in fish sperm may be used as indicator of water contamination with heavy metals and their bioaccumulations in testis of aquatic animals.
Vitellogenin assay by enzyme-linked immunosorbant assay as a biomarker of endocrine disruptor chemicals pollution
Ebrahimi M
Indian Journal of Occupational and Environmental Medicine , 2005,
Abstract: There is increasing evidence that many xenobiotic chemicals (called as endocrine disruptor chemicals, EDCs) through interfering with the endocrine system, have the capability to induce developmental and reproductive abnormalities in humans and animals. The yolk protein precursor vitellogenin (Vtg) has proved to be a simple and sensitive biomarker for assessing exposure of fish to EDCs, especially the estrogenic compounds. Work is ongoing to develop screening and testing programmes for endocrine disrupting effects of new chemicals, and in the focus of this development are the fish test species common carp ( Cyprinus carpio ). In this study, we have developed quantitative enzyme-linked immunosorbent assays (ELISA) for VTS in common carp. The working range of the ELISA was 11.25 - 2000 ng/ml (75 - 25% specific binding/maximum antibody binding [B/B0]) with a 50% B/B0 intra and interassay variation of 3.9% ( n = 10) and 12.5% ( n = 30), respectively. This ELISA is capable of detecting Vtg as low as 6 ng/ml, and can accurately detect Vtg in even 10 ml of plasma. The ELISA was applied to measurement of Vtg production by male carp ( C. carpio , Cyprinidae) fish exposure to ethynylestradiol. The results showed that the amount of Vtg produced in plasma of exposed fish increased in logarithmic order comparing to the control group and the ELISA described here could be used as an indicator of water pollution to estrogenic pollutants.
A Rapid ELISA Method for 17, 20b-dihydroxy-4-pregenen-3-one (17,20bP) Hormone Using Acetylcholinesterase Enzyme as Tracer
M Ebrahimi
Journal of Research in Medical Sciences , 2004,
Abstract: Background: During the past 15 years Enzyme Linked ImmunoSorbent Assay (ELISA) has been described as an alternative to radioimmunoassay for steroid detection. In addition to gonads, sperm itself is capable of producing reduced progesterone metabolites. In this study we introduced a method to extend the applicability of previous measures by describing a general preparation procedure for the enzyme label which is applicable to any steroid hormone. Methods: A simple and rapid Enzyme Linked Immunosorbant Assay (ELISA) is described and validated for 17,20β- dihydroxy-4-pregnen-3-one (17,20βP). A general procedure for preparation of the acetylcholinesterase labelled steroid is described which is applicable to any steroid. Results: Use of acetylcholinesterase tracer increased the sensitivity of assay so that reliable measurements of each steroid could be achieved with only 10 μl of plasma. ELISA was applied to measure of 17,20βP steroid production by sperm of trout which has sufficient amount of potent and active 20βHSD enzyme to convert 17α-hydroxy-4-pregnen-3-one (17αP) substrate to 17,20βP product. The results showed that a clear shift in 17,20βP production was found with increase in substrate concentration in all in vitro incubations. Conclusion: ELISA method presented in this study has greater sensitivity and accuracy compared to previously described method that uses radiolabelled substances. Keywords: Immunoassay, ELISA, Steroids, Hormone, Assay
Electron trajectories in free electron laser with realizable helical wiggler and ion channel guiding
S. Ebrahimi,M. Esmaeilzadeh
Iranian Journal of Physics Research , 2004,
Abstract: A detailed analysis of electron trajectories in a realizable helical wiggler free electron laser with ion channel guiding using electron (single particle dynamics) is presented. Conditions for stability of electron orbit have been investigated, calculations are made to illustrate. Conclusion shows that there are differences stable (unstable) condition(s) electron trajectories between ideal helical wiggler(2D) and realizable helical wiggler (3D).
Endocrine Disrupting Chemicals in Pesticides and Herbicide in Fars Province, Iran
M. Ebrahimi,N. Shamabadi
Pakistan Journal of Biological Sciences , 2007,
Abstract: Recent studies have shown that certain man-made compounds (including some pesticides and herbicide) through interfering with endocrine system, have the capability to induce developmental and reproductive abnormalities in humans and animals. Pesticides are currently being used in large scales in many developed and developing countries (including Iran), so this study has been conducted to determine the percentage of endocrine disruptor agents in pesticides used in Fars province. The results showed that more than 1,581,690 L of pesticides, in 86 different brands, have been used in Fars province during year 1380 and 25.93% (34 types) of them had at least one carcinogenic agents. At least 30 pesticides (711720 L, 44.99%) had one endocrine disruptor agent and therefore can be classified as environmental hormones or endocrine disrupting chemicals. The percentage of pesticides whom interfering with normal endocrine system activity were, 7.82% (66572 L), 4.54% (39975 L), 22.02% (348400 L), 5.12% (81000 L) and 21.18% (34500 L) of pesticides were antiestrogenic, antiandorgenic, antityroidic, antigonadotropin and anitestroid hormones, respectively. The results showed that about 50% of pesticides which currently being used in Fars province should be banned.
Use of Bacterial Indicators for Contamination in Drinking Water of Qom, Iran
N. Shamabadi,M. Ebrahimi
Journal of Applied Sciences , 2007,
Abstract: This study is performed to investigate the bacterial contamination of the water resources and the pipeline networks of the city. Faecal coliforms (such as Escherichia coli (E. coli) as the most important indicator of water contamination), non-faecal coliforms and Pseudomonas aeruginosa (which have recently been introduced as a new indicator of water contamination) as well as the number of phototrophic bacteria are examined. Samples collected from all wells, a big reservoir supplying big part of the city’s water (called Khordad 15 Dam), main pipeline networks, settling and resting reservoirs and finally treated water consumed by people under a sterile condition. The results showed 25% of samples from main water resources of Qom city were contaminated with confirm but no contamination detected in treated water. 16.7% of were samples were contaminated with Pseudomonas aeruginosa after subculturing to Acetamid broth, but 11.8% of treated water samples confirmed to be contaminated with this bacterium in the second subculture. Although the results of this study demonstrated the potential threats of bacterial contamination (such as coliforms) in water resources, Qom’s fresh water is safe and water treatment facilities there work quietly efficient and remove all coliform contaminations. The appearance of Pseudomonas aeruginosa contamination in drinking water is a sign of pipeline network cracks and erosions which require new efforts to repair and renew them.
The Applications of Bone Marrow-Derived Stem Cells to Induce Tolerance and Chimerism in Organ Transplantation
M. Ebrahimi,N. Aghdami
International Journal of Organ Transplantation Medicine , 2010,
Abstract: Progress in understanding the cellular and molecular biology of the immune system, in the second half of the 20th century brings the transplantation of replacement organs and tissues in clinical reality to cure disease. Immunosuppressive agents that are part of nearly every transplantationprocedure, are toxic to some extent and their chronic use predisposes the patient to the development of infection and cancer. Alternatives to immunosuppression include modulationof host immune system to reduce the immune response and the induction of a state of immunologic tolerance. Induction of hematopoietic mixed chimerism through donor bone marrowtransplantation offers a promising approach for tolerance induction as a prelude to organ transplantation. Furthermore, mesenchymal stromal cells have important effects on the host immunesystem and possess immune modulation properties that make them attractive for potential use in organ transplantation as immunosuppressant. Both modalities might potentially provide novel therapeutic options for treatment/prevention of rejection and/or repair of organ allografts through their multifaceted properties. In this review, evidences for the tolerogenic properties and mechanisms of hematopoietic mixed chimerism as well as mesenchymal stromal cells effectson allograft surveillance are summarized.
Determination of the Amount of Environmental Hormone Contamination in Raw Materials and Products of Bandar-e-Imam Petrochemical Complex
M. Ebrahimi,N. Shamabadi
Journal of Biological Sciences , 2007,
Abstract: Environmental hormone pollutants are synthetic chemicals which can disturb endocrine systems in human and wildlife if they enter body. Many diseases have been related to environmental hormones ranging from hormone dependent cancers to low sperm quality and quantity, infertility, wildlife population decline, developmental abnormalities and many more disruptions. Many of these pollutants are generally originated from oil and petroleum products. Therefore, estimating the amount of environmental hormone contaminations in raw materials and products of petrochemical complexes can illustrate the amount of society exposure to those dangerous pollutants. This study has looked at one of the biggest petrochemical complex, Bandar-e-Imam petrochemical complex, in Iran in order to determination of the extent of environmental hormones` contamination in material used and produced there. Bandar-e-Imam petrochemical complex produces 6.1 million tons of different products (3.5 million tons such as light and heavy chains polyethylene, polypropylene, PVC, artificial plastic, aromatic compounds (benzene, xylene) etc) every year. From 158 ingredients or products (7546928.47 tons) studied in this paper, 30 of them (3871447.8 tons) possess at least one environmental hormone pollutant. The most and the least percentage of the number of environmental hormones belong respectively to used and produced materials in CA unit (50%) and EDU unit (8%). No significant difference (p>0.05) were observed between raw materials used and final products made in petrochemical complex regarding to environmental hormone pollution.
Module amenability for Banach modules
Ebrahimi Bagha,D; Amini,M;
Cubo (Temuco) , 2011, DOI: 10.4067/S0719-06462011000200007
Abstract: we study the module amenability of banach modules. this is a natural generalization of johnson?s amenability of banach algebras. as an example we show that for a discrete abelian group g, lp(g) is amenable as an l1(g)-module if and only if g is amenable, where l1(g) is a banach algebra with pointwise multiplication.
Umbilical cord blood gases in newborns with or without nuchal cord: a comparative study
Shabani Zanjani M,Ebrahimi N
Tehran University Medical Journal , 2011,
Abstract: "nBackground: Entanglement of the umbilical cord around fetal neck has been reported to be associated with birth asphyxia. On the other hand, current evidence suggests that umbilical arterial pH analysis provides the most sensitive reflection of birth asphyxia. In this study we aimed to evaluate and compare the umbilical arterial hydrogen-ion concentration (pH) and to analyze the blood gases of neonates with or without nuchal cord."n "nMethods: In this cohort study, 92 newborns with and 95 without nuchal cords were enrolled at Shahid Akbar Abadi Hospital in Tehran, Iran between the years 2009 and 2010. From each newborn an umbilical arterial blood sample was collected to measure pH, base excess and blood gases."n "nResults: There were no statistically significant differences between newborns with or without nuchal cord regarding maternal age, gestational age, and history of pregnancy. The mean pH in the newborns with nuchal cord (7.21±0.1) was significantly less than the value in the newborns without the cord (7.28±0.1), (P<0.001). In contrast, the mean base excess in the newborns with nuchal cord was more than the ones without the cord (P<0.001). Seven newborns (7.9%) in the group with nuchal cord passed meconium during labor while only one (1%) newborn did so in the other group."n "nConclusion: Our finding showed that nuchal cord had a significant relationship with acidosis in newborns with nuchal cord. However, this finding needs further investigation to reach a common conclusion. "n

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