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101.
102.
Previous studies indicate that release of superoxide radicals during coronary reperfusion following occlusion may relate to the loss of endothelium-dependent coronary arterial relaxation. We examined coronary arterial ring relaxation in dogs subjected to temporary circumflex (Cx) coronary artery occlusion and treated with saline or the superoxide radical scavenger superoxide dismutase (SOD). In dogs treated with saline, Cx coronary ring relaxation in response to leukotriene D4 (LTD4) and acetylcholine (ACh) was attenuated (p less than 0.01), but coronary relaxation in response to nitroglycerin was preserved, suggesting loss of endothelium-dependent relaxation following coronary reperfusion. In contrast, Cx coronary relaxation in response to LTD4 and ACh was preserved in the SOD-treated dogs (p less than 0.01 compared to saline-treated dogs). To further examine the role of superoxide radicals in the loss of endothelium-dependent relaxation, normal nonischemic canine coronary artery and rat aortic rings were exposed to a superoxide radical generating system of xanthine and xanthine oxidase in vitro. Xanthine plus xanthine oxidase treatment caused a significant (p less than 0.01) decrease in the relaxant effects of ACh. Pretreatment of rat aortic rings with SOD protected against the loss of ACh-induced relaxation. These observations suggest that release of superoxide radicals during reperfusion is the basis of loss of endothelium-dependent coronary arterial relaxation. Treatment with superoxide radical scavengers prior to coronary reperfusion protects against this loss. 相似文献
103.
Pankaj K. Sikka Kenneth E. McMartin 《In vitro cellular & developmental biology. Animal》1996,32(5):285-291
Summary Anin vitro model to establish primary and subcultures of rat kidney proximal tubule (RPT) cells is described. After excising the kidneys
and separating the cortex, the cortical tissue is digested with the enzyme DNAse-collagenase (Type I) resulting in a high
yield of viable RPT Cells. The isolated RPT cells are then seeded onto rat tail collagen-coated surfaces and grown to confluency
in a serum-free, hormonally defined medium. The cell yield can be increased by transfering the conditioned medium on Day 1
to more rat tail collagen-coated surfaces. RPT cell attachment and morphology was better on rat tail collagen-coated surfaces
than on bovine collagen Type I coated surfaces. The culture medium was a 1∶1 mixture of Ham’s F-12 and Dulbecco’s modified
Eagle’s medium supplemented with bovine serum albumin, insulin, transferrin, selenium, hydrocortisone, triiodothyronine, epidermal
growth factor, and glutamine. The RPT cells became confluent in 7–10 d, at which point they could be subcultured by trypsinizing
and growth in the same medium. In some studies, 10 ng/ml cholera toxin was added to the culture medium. We could passage the
RPT cells up to 14 times in the presence of cholera toxin. The cells were investigated for activity of several markers. The
cells were histochemically positive for alkaline phosphatase and γ-glutamyl transpeptidase activity and synthesized the intermediate
filament pankeratin. The RPT cells displayed apically directed sodium-dependent active glucose transport in culture. Hence,
the RPT cells retain structural and functional characteristics of transporting renal epithelia in culture. This rat cell culture
model will be a valuable tool for substrate uptake and nephrotoxicity studies. 相似文献
104.
Jawahar Mehta M.D. Paulette Mehta M.D. Don Hay Ph.D. 《Prostaglandins & other lipid mediators》1982,24(6):751-761
These experiments were conducted to determine the effects of dipyridemole on human platelet aggregation, platelet thromboxane A2 (TXA2) and human vessel wall prostacyclin (PGI2) generation. Dipyridamole in varying concentrations (5 to 50 μg/ml) had no direct effect on ADP-induced platelet aggregation in vitro, but it potentiated PGI2-induced platelet aggregation inhibition at these concentrations. Dipyridamole also inhibited arachidonic acid-induced platelet TXA2 generation at these concentrations. In continuously perfused umbilical vein segments, dipyridamole treatment resulted in stimulation of PGI2 release determined by bioassay and by measurement of its stable metabolite 6-keto-PGF1α. Minimum concentration of dipyridamole causing PGI2 release was 50 μg/ml. These in vitro studies suggest that anti-thrombotic effects of dipyridamole in man are mediated mainly by potentiation of PGI2 activity and to some extent by TXA2 suppression. Stimulation of PGI2 release by human vessels may not be seen in usual therapeutic concentrations. 相似文献
105.
Gao X Xu N Sekosan M Mehta D Ma SY Rahman A Malik AB 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(5):2895-2901
The in vivo contributions of CD18 integrin-dependent and -independent mechanisms in mediating the increases in lung neutrophil (polymorphonuclear leukocyte; PMN) sequestration and microvascular permeability are not well understood. We determined the time course of these responses to Gram-negative sepsis in the mouse lung and addressed the specific contributions of CD18 integrins and ICAM-1. PMN sequestration in the lung was assessed by morphometric analysis, and transalveolar PMN migration was assessed by bronchoalveolar lavage. Lung tissue PMN number increased by 6-fold within 1 h after i.p. Escherichia coli challenge; this value peaked at 3 h (7-fold above control) and decreased at 12 h (3.5-fold above control). PMN migration into the airspace was delayed; the value peaked at 6 h and remained elevated up to 12 h. Saturating concentrations of anti-CD18 and anti-ICAM-1 mAbs reduced lung tissue PMN sequestration and migration; however, peak responses at 3 and 6 h were inhibited by 40%, indicating that only a small component of PMN sequestration and migration was CD18 dependent at these times. In contrast to the time-dependent decreased role of CD18 integrins in mediating PMN sequestration and migration, CD18 and ICAM-1 blockade prevented the increase in lung microvascular permeability and edema formation at all times after E. coli challenge. Thus, Gram-negative sepsis engages CD18/ICAM-1-independent mechanisms capable of the time-dependent amplification of lung PMN sequestration and migration. The increased pulmonary microvascular permeability induced by E. coli is solely the result of engagement of CD18 integrins even when PMN accumulation and migration responses are significantly CD18 independent. 相似文献
106.
Starting from previously reported cis-Ru(MeL)2Cl2, where MeL is 4,4,4′,4′-tetramethyl-2,2′-bisoxazoline, cis-Ru(MeL)2Br2 (1), cis-Ru(MeL)2I2 (2), cis-Ru(MeL)2(NCS)2 · H2O (3), cis-Ru(MeL)2(N3)2 (4) and cis-[Ru(MeL)2(MeCN)2](PF6)2 · (CH3)2CO (5) are synthesised. The X-ray crystal structures of complexes 1, 2, 3 and 5 have been determined. All the five new complexes have been characterized by FTIR, ESIMS and 1H NMR. In cyclic voltammetry in acetonitrile at a glassy carbon electrode, the complexes display a quasireversible Ru(II/III) couple in the range 0.32-1.71 V versus NHE. The Ru(II/III) potentials yield a satisfactorily linear correlation with Chatt’s ligand constants PL for the monodantate ligands. From the intercept and by comparing the known situation in Ru(2,2′-bipyridine)2L2, it is concluded that MeL, a non-aromatic diimine, is significantly more π-acidic than 2,2′-bipyridine. 相似文献
107.
Sanjay R. Mehta Xing-Quan Zhang Celsa Spina Kwang-Poo Chang 《Experimental parasitology》2010,126(4):617-620
High-throughput drug screening methods against the intracellular stage of Leishmania have been facilitated by the development of in vitro models of infection. The use of cell lines rather than primary cells facilitates these methods. Peripheral blood mononuclear cell (PBMC) derived macrophages and THP-1 cells were infected with stationary phase egfp transfected Leishmania amazonensis parasites and then treated with anti-leishmanial compounds. Drug activity was measured using a flow cytometric approach, and toxicity was assessed using either the MTT assay or trypan blue dye exclusion. Calculated EC50’s for amphotericin B, sodium stibogluconate, and miltefosine were 0.1445 ± 0.0005 μg/ml, 0.1203 ± 0.018 mg/ml, and 26.71 μM using THP-1 cells, and 0.179 ± 0.035 μg/ml, 0.1948 ± 0.0364 mg/ml, and 13.77 ± 10.74 μM using PBMC derived macrophages, respectively. We conclude that a flow cytometric approach using egfp transfected Leishmania species can be used to evaluate anti-leishmanial compounds against the amastigote stage of the parasite in THP-1 cells with excellent concordance to human PBMC derived macrophages. 相似文献
108.
Hiesinger PR Zhai RG Zhou Y Koh TW Mehta SQ Schulze KL Cao Y Verstreken P Clandinin TR Fischbach KF Meinertzhagen IA Bellen HJ 《Current biology : CB》2006,16(18):1835-1843
Specifying synaptic partners and regulating synaptic numbers are at least partly activity-dependent processes during visual map formation in all systems investigated to date . In Drosophila, six photoreceptors that view the same point in visual space have to be sorted into synaptic modules called cartridges in order to form a visuotopically correct map . Synapse numbers per photoreceptor terminal and cartridge are both precisely regulated . However, it is unknown whether an activity-dependent mechanism or a genetically encoded developmental program regulates synapse numbers. We performed a large-scale quantitative ultrastructural analysis of photoreceptor synapses in mutants affecting the generation of electrical potentials (norpA, trp;trpl), neurotransmitter release (hdc, syt), vesicle endocytosis (synj), the trafficking of specific guidance molecules during photoreceptor targeting (sec15), a specific guidance receptor required for visual map formation (Dlar), and 57 other novel synaptic mutants affecting 43 genes. Remarkably, in all these mutants, individual photoreceptors form the correct number of synapses per presynaptic terminal independently of cartridge composition. Hence, our data show that each photoreceptor forms a precise and constant number of afferent synapses independently of neuronal activity and partner accuracy. Our data suggest cell-autonomous control of synapse numbers as part of a developmental program of activity-independent steps that lead to a "hard-wired" visual map in the fly brain. 相似文献
109.
Cardioprotective effect of lycopene in the experimental model of myocardial ischemia-reperfusion injury 总被引:1,自引:0,他引:1
Shervington A Cruickshanks N Wright H Atkinson-Dell R Lea R Roberts G Shervington L 《Molecular and cellular biochemistry》2006,283(1-2):1-9
The continuous advancements in cancer research have contributed to the overwhelming evidence of the presence of telomerase
in primary and secondary tumours together with hsp90 and c-Myc. This review will discuss the important role of telomerase together with hsp90 and c-Myc within the initiation and progression of gliomas. Also it will review the differential expression of these genes in the different
grades of gliomas and the possibility of new treatments targeting these specific genes. 相似文献