scholarly journals Development and radiolabeling of lipid nanoparticles with [99mTc]Tc-HMPAO: Characterization, stability, cytotoxicity and cell binding studies

2022 ◽  
Vol 26(1) (26(1)) ◽  
pp. 1105-1118
Meliha EKİNCİ Emre ÖZGENÇ ◽  
Emine Selin DEMİR ◽  
1985 ◽  
Vol 63 (12) ◽  
pp. 1241-1249
Audrey J. Goldner-Sauvé ◽  
Abraham Fuks ◽  
Ronald D. Guttmann

The class II antigens of the ACI rat were studied using both conventional alloantisera and monoclonal antibodies. By sequential immunoprecipitation experiments and cell binding studies, alloantisera were shown to contain antibodies to both the RT1.B and the RT1.D gene products. Using one- and two-dimensional gel electrophoresis, the structures of these gene products were shown to be distinguishable. The importance of these differences for the immune response and antigen presentation is discussed.

1984 ◽  
Vol 98 (2) ◽  
pp. 444-448 ◽  
R Snyderman ◽  
M C Pike ◽  
S Edge ◽  
B Lane

The binding characteristics of the oligopeptide chemoattractant receptor on guinea pig macrophages and macrophage membrane preparations were characterized using detailed binding studies and computer analysis. Viable macrophages bound the radiolabeled chemoattractant N-formyl-methionyl-leucyl-[3H]phenylalanine with single dissociation constant (KD) of 18.4 +/- 4.6 nM with 15,300 +/- 1,800 sites per cell. Binding data from membrane preparations indicated the presence of two classes of binding sites with KD of 1.5 +/- 0.4 nM and 25.5 +/- 11.0 nM. Approximately 23% of the receptors were in the high affinity state. In the presence of added guanine nucleotide di- or triphosphates, the high affinity receptors in the membrane preparations were converted to low affinity states with no change in the total receptor number. Nonhydrolyzable derivatives of GTP were most potent in converting the receptor from its high to low affinity state. These data suggest that the affinity state of the oligopeptide chemoattractant receptor in macrophages is regulated by guanine nucleotides and GTPase, implying that the transduction mechanisms of this receptor may be controlled by a guanine nucleotide regulatory unit.

2004 ◽  
Vol 186 (11) ◽  
pp. 3480-3491 ◽  
John G. Kenny ◽  
Stephen McGrath ◽  
Gerald F. Fitzgerald ◽  
Douwe van Sinderen

ABSTRACT Tuc2009 is a P335-type member of the tailed-phage supergroup Siphoviridae and was originally identified as a resident prophage of the gram-positive bacterium Lactococcus lactis UC509. A Tuc2009 gene designated tal2009 which is located within the morphogenic module was shown to specify a lytic activity within the 3′ portion of its coding region. Comparative sequence analysis indicated that the cell wall-degrading part of Tal2009 is a member of the M37 protein family and that Tal2009 lacks a cell-binding domain, a finding supported by binding studies. Tal2009 appears to undergo self-mediated posttranslational processing in both L. lactis and Escherichia coli. Antibodies directed against a purified C-terminal portion of Tal2009 were used for immunoelectron microscopy, which showed that Tal2009 is located at the tail tip of Tuc2009. Antibody neutralization studies demonstrated that Tal2009-directed antibodies inhibited the ability of phage to mediate host lysis by more than 100-fold. These data indicate that tal2009 encodes a tail-associated lysin involved in localized cell wall degradation, thus allowing the Tuc2009 DNA injection machinery access to the membrane of its bacterial host.

2005 ◽  
Vol 61 (12) ◽  
pp. 1568-1578 ◽  
Daniel E. Holloway ◽  
Gayatri B. Chavali ◽  
Michelle C. Hares ◽  
Vasanta Subramanian ◽  
K. Ravi Acharya

Biochimie ◽  
2004 ◽  
Vol 86 (1) ◽  
pp. 1-6 ◽  
Ramsés López ◽  
John Valbuena ◽  
Hernando Curtidor ◽  
Alvaro Puentes ◽  
Luis E. Rodríguez ◽  

Acta Tropica ◽  
2000 ◽  
Vol 75 (3) ◽  
pp. 349-359 ◽  
Ramsés López ◽  
Mauricio Urquiza ◽  
Hemando Curtidor ◽  
Jorge Eduardo Caminos ◽  
Hemando Mora ◽  

1989 ◽  
Vol 170 (3) ◽  
pp. 913-931 ◽  
H Gerlach ◽  
H Lieberman ◽  
R Bach ◽  
G Godman ◽  
J Brett ◽  

Some in vivo observations have suggested that growing or perturbed endothelium, such as that which occurs during angiogenesis, is more sensitive to the action of cytokines (TNF/cachectin, TNF, or IL-1) than normal quiescent endothelial cells. This led us to examine the responsiveness of endothelium to TNF as a function of the growth/motile state of the cell. TNF-induced modulation of endothelial cell surface coagulant function was half-maximal at a concentration of approximately 0.1 nM in subconfluent cultures, whereas 1-2 nM was required for the same effect in postconfluent cultures. Perturbation of endothelial cell shape/cytoskeleton was similarly more sensitive to TNF in subconfluent cultures. Consistent with these results, radioligand binding studies demonstrated high affinity TNF binding sites, Kd approximately 0.1 nM on subconfluent cultures, whereas only lower affinity sites (Kd approximately 1.8 nM) were detected on postconfluent cultures. The mechanisms underlying this change in the affinity of endothelium for TNF were studied in four settings. Crosslinking experiments with 125I-TNF and endothelium showed additional bands corresponding to Mr approximately 66,000 and approximately 84,000 with subconfluent cultures that were not observed with postconfluent cultures. Experiments with X-irradiated endothelium, whose growth but not motility was blocked, indicated that proliferation was not required for induction of high affinity TNF sites. Postconfluent endothelium, triggered to enter the proliferative cycle by microbutuble poisons, expressed high affinity TNF binding sites together with changes in cell shape/cytoskeleton well before their entry into S phase. Using wounded postconfluent monolayers, cells that migrated into the wound and those close to the wound edge displayed enhanced TNF binding and modulation of coagulant properties. These results suggest a model for targetting TNF action within the vasculature; regulation of high affinity endothelial cell binding sites can direct TNF to activated cells in particular parts of the vascular tree.

1996 ◽  
Vol 1 (3) ◽  
pp. 173-179 ◽  
Bing-Yin Wang ◽  
Josef Niebauer ◽  
Alan H Singer ◽  
Philip S Tsao ◽  
John P Cooke

The purpose of this study was to determine if the calcium entry antagonist felodipine inhibited intimal lesion formation in hypercholesterolemic rabbits, and to determine if this was due to an effect upon monocyte and/or endothelial determinants of this interaction. Twenty-three male New Zealand White rabbits received the following treatment regimen for 10 weeks: normal chow (NP, n = 3); normal chow with felodipine infusion (NF, n=6); 0.5% cholesterol chow (CP, n = 7); or 0.5% cholesterol chow and felodipine infusion (CF, n=7). After 10 weeks blood was collected for biochemical measurements and mononuclear cell binding assays, and thoracic aortae were harvested for vascular reactivity studies and histomorphometry. In the animals receiving normal chow, felodipine did not significantly affect blood pressure, plasma cholesterol levels, binding studies, vascular reactivity, or structure; therefore these animals were analyzed as one group (N). Plasma cholesterol levels were significantly elevated in groups receiving the 0.5% cholesterol diet (N, 29±3 mg/dl; CP, 1221±73 mg/dl; CF, 979±108 mg/dl). High-density lipoprotein cholesterol was not different between the groups (25±4 vs 23±4 vs 27±4 mg/dl; N vs CF vs CP respectively; p=NS). Cholesterol feeding markedly augmented the adhesiveness of mononuclear cells, as demonstrated by a 250% increase in cell binding. Felodipine did not alter the adhesiveness of mononuclear cells in hypercholesterolemic animals. Cholesterol feeding significantly impaired endothelium-dependent relaxations. Endothelium-dependent relaxations were restored by felodipine treatment as reflected by the maximal responses to acetylcholine (40±7% vs 58±4% vs 67±5%; CP vs CF vs N respectively). The improvement in endothelium-dependent relaxation in the felodipine-treated animals was associated with a 2.2-fold reduction in lesion surface area of the thoracic aorta (8.2±6.3% vs 18.2±9.5%; CF vs CP; p<0.01). Moreover, the intima/media ratio reflecting lesion thickness was substantially reduced by felodipine treatment (0.05±0.02 vs 0.20±0.07; CF vs CP; p=0.006). Ex vivo studies revealed that felodipine inhibited the adhesiveness of vascular endothelium, but not mononuclear cells, derived from hypercholesterolemic animals. Low-dose felodipine appears to inhibit monocyte-endothelial interaction, as indicated by a reduction in the formation of lesions in hypercholesterolemic animals. This effect is not due to an alteration in adhesiveness of mononuclear cells. The salutary effect of felodipine is associated with an increase in vascular nitric oxide activity which may reduce endothelial adhesiveness.

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