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排序方式: 共有746条查询结果,搜索用时 125 毫秒
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Xainli J Cole-Tobian JL Baisor M Kastens W Bockarie M Yazdani SS Chitnis CE Adams JH King CL 《Infection and immunity》2003,71(5):2508-2515
Erythrocyte invasion by Plasmodium vivax is completely dependent on binding to the Duffy blood group antigen by the parasite Duffy binding protein (DBP). The receptor-binding domain of this protein lies within a cysteine-rich region referred to as region II (DBPII). To examine whether antibody responses to DBP correlate with age-acquired immunity to P. vivax, antibodies to recombinant DBP (rDBP) were measured in 551 individuals residing in a village endemic for P. vivax in Papua New Guinea, and linear epitopes mapped in the critical binding region of DBPII. Antibody levels to rDBP(II) increased with age. Four dominant linear epitopes were identified, and the number of linear epitopes recognized by semi-immune individuals increased with age, suggesting greater recognition with repeated infection. Some individuals had antibodies to rDBP(II) but not to the linear epitopes, indicating the presence of conformational epitopes. This occurred in younger individuals or subjects acutely infected for the first time with P. vivax, indicating that repeated infection is required for recognition of linear epitopes. All four dominant B-cell epitopes contained polymorphic residues, three of which showed variant-specific serologic responses in over 10% of subjects examined. In conclusion, these results demonstrate age-dependent and variant-specific antibody responses to DBPII and implicate this molecule in partial acquired immunity to P. vivax in populations in endemic areas. 相似文献
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Khaliq A Dunk C Jiang J Shams M Li XF Acevedo C Weich H Whittle M Ahmed A 《Laboratory investigation; a journal of technical methods and pathology》1999,79(2):151-170
Early placental development occurs in an environment of relative hypoxia. Hypoxia promotes angiogenesis and up-regulates vascular endothelial growth factor (VEGF) expression while it down-regulates placenta growth factor (PIGF) that possess 53% homology with VEGF. Morphological studies show poor placental vascular development and an increase in the mitotic index of cytotrophoblasts in intrauterine growth restriction (IUGR). We hypothesized that the reported relatively high oxygen level in the intervillous space in contact with IUGR placental villi will limit angiogenesis by changes in VEGF and PIGF expression and function. Western immunoblot analysis demonstrates a diametric expression of PIGF and VEGF proteins throughout pregnancy with PIGF levels increasing and VEGF levels decreasing, consistent with placental oxygenation. In IUGR placentae, the ratio of PIGF/GAPDH mRNA was increased by 2.3-fold (p < 0.03) and PIGF protein levels were also increased, (p < 0.05) as compared with gestationally-matched normal placentae. PIGF mRNA and protein were localized to the trophoblast bilayer and villous mesenchyme of the human placenta throughout gestation. In vitro studies demonstrated that increasing oxygen tension (hyperoxia) up-regulated PIGF protein in term placental villous explants, whereas hypoxic culture of a term trophoblast choriocarcinoma cell line (BeWo) down-regulated PIGF mRNA and protein and VEGFR-1 (Flt-1) autophosphorylation. The addition of PIGF-1 to a spontaneously transformed first trimester cytotrophoblast cell line stimulated DNA synthesis while PIGF-2 had little effect. VEGF and PIGF exert their biological actions by means of a common receptor VEGFR-1. In the first trimester trophoblast cells, PIGF-1 increased the association of phosphorylated extracellular signal-related kinase (ERK) with VEGFR-1 immunoprecipitates while both PIGF-1 and PIGF-2 also potentiated endogenous VEGF mediated association of phosphorylated extracellular related kinase (ERK) with VEGFR-2 (KDR). More importantly, the addition of PIGF-1 had little effect while PIGF-2 inhibited cell growth in cultured endothelial cells derived from human umbilical vein. Nitric oxide (NO) is reported to promote angiogenesis and PIGF-2 inhibited the basal release of NO from the first trimester trophoblast. The tissue expression and functional studies support the hypothesis of "placental hyperoxia" in early-onset IUGR because hypoxia down-regulates trophoblast PIGF levels, PIGF expression is increased in IUGR, and PIGF-2 inhibits endothelial cell growth. Taken together, these changes provide a cellular explanation for the observed poor angiogenesis in the pathogenesis of IUGR and show that the two PIGF isoforms may modulate trophoblast and endothelial cell function differently, possibly through potentiation of VEGF mediated activation of VEGF-2. 相似文献
4.
Abbas Haghparast Jamal Shams Ali Khatibi Amir-Mohammad Alizadeh Mohammad Kamalinejad 《Neuroscience letters》2008
The problem of morphine tolerance and dependence is a universal phenomenon threatening social health everywhere the world. The major objective of this paper was to investigate the effects of fruit essential oil (FEO) of Cuminum cyminum on acquisition and expression of morphine tolerance and dependence in mice. Animals were rendered dependent on morphine using the well-established method in which was morphine (50, 50, 75 mg/kg; s.c.) injected three times daily for 3 days. In experimental groups, administration of FEO (0.001, 0.01, 0.1, 0.5, 1 and 2%; 5 ml/kg; i.p.) or Tween-80 (5 ml/kg; i.p.) was performed 60 min prior to each morphine injection (for acquisition) or the last injection of morphine on test day (for expression). Morphine tolerance was measured by tail-flick before and after administration of a single dose of morphine (50 mg/kg; s.c.) in test day (4th day). Morphine dependence was also evaluated by counting the number of jumps after injection of naloxone (5 mg/kg; i.p.) on the test day. The results showed that Cumin FEO, only at the dose of 2%, significantly attenuated the development of morphine tolerance (P < 0.01) and dependence (P < 0.05) while it could be significantly effective on expression of morphine tolerance (1 and 2%) and dependence (0.5, 1 and 2%) in a dose-dependent manner. Solely Cumin FEO injection (0.001–2%) did not show any analgesic effect. In conclusion, the essential oil of Cuminum cyminum seems to ameliorate the morphine tolerance and dependence in mice. 相似文献
5.
Iliac vein compression syndrome: a new method of treatment 总被引:26,自引:0,他引:26
Iliac vein compression syndrome (May-Thurner syndrome) is caused by compression of the left iliac vein against the pelvic rim by the right iliac artery. Serious vascular sequelae to the leg can result if this is not recognized and corrected in a timely fashion. The condition, often underdiagnosed, is thought to be present in approximately 20 per cent of the adult population. Previously, a major vascular operation with a significant hospital stay was required to correct this compression. As a nonsurgical option, we elected balloon dilation of the stenosed iliac vein, with insertion of a venous stent to maintain the restored lumen. Two patients who had this procedure have been followed for 12 months; venograms show continued patency of the iliac vein with no pressure gradient present. This procedure is safe and cost effective, and it requires a minimal hospital stay. 相似文献
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A bisensory method was developed for determining the psychometric functions and absolute thresholds for odor and sensory irritation of two odorous irritants. Individual and group thresholds for formaldehyde or pyridine were measured for 31 age-matched subjects (18?C35?years old). P 50 absolute thresholds were for formaldehyde odor 110?ppb (range 23?C505), for pyridine odor 77?ppb (range 20?C613), and for pyridine irritation 620?ppb (range 90?C3,656); too few subjects?? formaldehyde irritation thresholds were possible to determine (human exposures limited to 1?ppm). In spite of large interindividual differences, all thresholds for irritation were higher than for odor. The average slopes of the 62 psychometric functions for odor and the 32 possible for sensory irritation were highest for formaldehyde odor (83% per log ppb) and equal for pyridine odor and irritation (68% per log ppb). The bisensory method for measuring odor and sensory irritation jointly produced detection functions and absolute thresholds compatible with those earlier published; however, a steeper slope for sensory irritation than odor was expected for pyridine. The bisensory method is intended for measuring odor and sensory irritation to broadband mixtures and dynamic exposures, like indoor air. 相似文献
9.
The enterohepatic circulation of thyroid hormones is increased in thyrotoxicosis. Bile-salt sequestrants bind thyroid hormones in the intestine and thereby increase their fecal excretion. Based on these observations, the use of cholestyramine has been tried. The present study evaluates the effect of low doses of cholestyramine as an adjunctive therapy in the management of hyperthyroidism. In a prospective, randomized, double-blind, placebo-controlled trial, 45 patients with newly diagnosed hyperthyroid Graves' disease were randomly assigned into the following treatment protocols: group I, cholestyramine 2 g BID, methimazole and propranolol; group II, cholestyramine 1 g BID, methimazole and propranolol; group III, placebo powder, methimazole and propranolol. The fixed dose of methimazole (30 mg/d) and propranolol (40 mg/d) was used. The study period was 4 weeks. Serum total triiodothyronine and free thyroxin were measured at baseline, and at the ends of the second and the fourth week of the study. The serum thyroid hormone levels decreased more rapidly and to a greater extent in the cholestyramine-treated groups. All of the patients in group I had achieved euthyroid state at the end of the study. We conclude that low dose of cholestyramine is an effective and well-tolerated adjunctive agent in the treatment of hyperthyroid Graves' disease. 相似文献
10.
Majid Nimrouzi Omid Sadeghpour Mohammad Hadi Imanieh Mohammadreza Shams Ardekani Alireza Salehi Mohamad Bagher Minaei Mohammad M. Zarshenas 《Iranian journal of pediatrics.》2015,25(2)