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551.
Abstract: The secretion of catecholamines and the labelling of phospholipids with 32Pi has been studied in slices of bovine adrenal medulla. Both nicotinic and muscarinic drugs provoked catecholamine secretion, but only muscarinic activation was accompanied by the increased labelling of phosphatidylinositol and phosphatidic acid.  相似文献   
552.
ABSTRACT

The concentrations of selected heavy metals including cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni) and iron (Fe) in stems and leaves of Artemisia herba-alba medicinal plant and soil samples were evaluated. Results showed that there in heavy metal concentrations of washed and unwashed parts of A. herba-alba from northern site (Irbid), Middle site (Al-Mafraq), and Souhern site (Ma’an) (P < .05). Moreover, the results of this study revealed that there is a correlation between heavy metal levels in medicinal plants and their concentrations in soil. Two standard reference materials of plant (SRM 1790a; spinach, CRM 281; ryegrass) and a standard reference material of soil (GBW 07406) were examined to validate the method used. There were good agreements between the measured values of these standard reference materials and their certified values. In addition to that high recoveries for tested elements were ranged between 91.7–97.7%, 90–96.6%, and 92.2–97.7% in (CRM281, ryegrass), (SRM1570a, spinach) and (GBW 04706, soil) respectively. It is reasonable to conclude that the variation in metal concentration from site to another site as well as from element to another element may be due to the different factors such as traf?c volumes, the wind directions, the soil nature, and the element behavior.

Based on the results obtained, the health authorities will take in consideration these useful information and direct the residents about the risk of these pollutants.  相似文献   
553.
Varicocele is an important cause of infertility in men. The exact mechanism by which varicocele depresses spermatogenesis is unknown but probably the retrograde flow of blood rich in catecholamines into the testes plays a major role.Because subfertile semen qualities are present in a large percentage of men with varicocele and because the response to surgical procedures is very good, high ligation of the left internal spermatic vein is recommended in men with varicocele and infertility.  相似文献   
554.
We examined Se in urine of 170 Saudi Arabian diabetics (19 insulin-dependent [type 1] and 151 insulin-independent [type 2]) and in an equal number of control subjects of the same origin by measuring the ratio of the concentration of this metal (CSe) to that of creatinine in urine (Ccreat) for each subject. The mean (and SEM) of CSe/Ccreat for the control subjects was 56 (2.9) μmol/mol creat, whereas, the value for the diabetics combined or separated into type 1 and type 2 was 56.7 (3.2), 51.5 (6.3), and 57.4 (3.5) μmol/mol creat, respectively. With the exception of type 2 diabetics who were treated with insulin in addition to oral hypoglycemic and diet (35 patients) (mean [SEM]=43 (4.3) μmol/mol creat), there was no significant difference in CSe/Ccreat between the diabetics and control subjects. Also, there was no significant correlation between CSe/Ccreat and age, sex, or weight of diabetics, whereas, the correlation with the degree of diabetic control was significant (p≤0.0136). Of all diabetes-associated disorders (cardiovascular diseases, neuropathy, ophthalmologic diseases, infections, and hepatic disease), only ophthalmologic diseases appears to cause a significant (p≤0.05) reduction in CSe/Ccreat, but only among type 2 diabetics. Inasmuch as Se status is reflected by urinary Se, healthy Saudi Arabians appear to have Se status that is comparable or higher than those reported for other populations.  相似文献   
555.
We have analyzed a gene, designated VEB4 , that is expressed transiently in very early blastulae of the sea urchin, Strongylocentrotus purpuratus . Sequence analysis of the complete open reading frame shows that VEB4 encodes an unusual, highly charged protein with a pl of 9.55. We show here that VEB4 mRNA accumulate in a spatial pattern that is indistinguishable from that of two other recently described genes encoding metallo-endoproteases, SpAN , related to astacin and SpHE , the hatching enzyme (Reynolds et al . 1992). VEB4 and other members of this gene set encode the earliest strictly zygotic gene products that have been identified. The asymmetric accumulation of VEB4 mRNA in non-vegetal blastomeres of the 16 cell embryo and their descendants reflects the animal-vegetal maternal developmental axis.  相似文献   
556.
557.
Early steps of tissue invasion by Entamoeba histolytica are mediated by adhesion and migration through matrix components such as fibronectin with the participation of the actin cytoskeleton. Striking differences in their produced structures, movement, and migration were found. These observations suggest differential changes in their ability to organize the actin cytoskeleton and, therefore, to modify its morphology after adhesion to fibronectin. To understand these observations, we explore deeper the cytoskeleton pathway of E. histolytica compared to Entamoeba dispar, analyzing the activation and involvement of actin cytoskeleton regulatory proteins such as small GTPases (Rho, Rac1 and Cdc42), myosin IB, paxillin, alpha‐actinin, and ARP2/3 during interaction with fibronectin. Results showed a higher activation of Rac1 in E. histolytica compared to E. dispar, while Cdc42 and RhoA were equally activated in both amebae; besides, variations in the amount of myosin IB, paxillin, and ARP2/3 were detected among these species, coinciding and reflected in formation of lamellipodia in E. histolytica and filopodia in E. dispar. These could partially explain the higher invasive capacity of E. histolytica compared to E. dispar, due to its pleomorphic ability, high motility, migration, activation, and abundance of proteins involved in the cytoskeleton arrangement.  相似文献   
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