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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A simple spectrophotometric method was developed to quantitate micromolar concentrations of a bifunctional DTPA ligand in DTPA monoclonal antibody (mAb) conjugates. Titration of a brightly colored 1:2 yttrium (III) complex of arsenazo III with the ligand 1B4M-DTPA obeyed Beer's law over the concentration range 0-2.0 microM 1B4M-DTPA at 652 nm. From a calibration plot of absorbance versus 1B4M molarity, concentrations of 1B4M-DTPA conjugated to mAb were determined. Mole ratios of 1B4M-DTPA to mAb agreed satisfactorily with the ratios obtained by a radioanalytical technique using carbon-14-labeled 1B4M-DTPA and a binding assay using 111In. The spectrophotometric method was applied successfully to the preparation of 1B4M-DTPA mAb anti-TAC, a mAb conjugate used in clinical trials of 90Y radioimmunotherapy.
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PMID:Spectrophotometric method for the determination of a bifunctional DTPA ligand in DTPA-monoclonal antibody conjugates. 139 Sep 90

The complexon CaDTPA was injected into tumour-bearing mice in concentrations of 0.05, 0.1, 0.3, and 0.6 mole/l (pH:6) 30 min after the 169Yb-injection. 100 microliters of a 0.3 M CaDTPA solution were injected at different time points (simultaneously, 2, 5, 10, 20, 30, 40 and 50 min, 1, 1.25, 1.5, 2.5 and 10 h) after 169Yb-citrate injection. The animals were killed 24 h after radionuclide administration. A strong radioactivity decrease was observable 24 h p.i. not only in blood, liver, spleen, muscle and bone but also in the tumour if CaDTPA was administered within the first 2 h after ytterbium injection. Thereafter no change in radioactivity could be achieved by DTPA. A time phase in which the Yb could be eliminated from the tissues by means of DTPA (time intervals < 2 h) was distinguishable from a time phase in which it was not attainable for DTPA (time intervals > 5 h). This indicates that the incorporation of Yb into the cells is completed after 5 h and that the metals are intracellularly bound, probably to the lysosomes. Improvements of the scintigraphic tumour detection cannot be expected from the use of complexons.
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PMID:[The effect of Ca-diethylenetriamine pentaacetate on the bio-behavior of tumor-affine metal complexes]. 149 64

In an attempt to improve bifunctional chelate labelling of Mab, we investigated the use of a polyamino acid backbone for multiple DTPA substitutions. Poly-L-lysine (PL) (3.8 Kd, n = 25) was partially acetylated with MADTPA to yield 11 moles of DPTA per mole of PL. The average numbers of DTPA on PL were directly quantified with MADTPA-C-14. The remaining epsilon amino groups on PL-DTPA (I) were measured with TNBS reagent. A selective maleimide derivatization of (I) with S-SMPB yielded (II), which contains 2.3 moles of maleimide groups per mole of (I). The sulfhydryl activation of Mab-TP41.2F(ab')2 with 2-Iminothiolane hydrochloride produced (III), containing 1.3 moles of sulfhydryl groups per mole of Mab. Compounds (II) and (III) were combined to form a single thioether-spaced chain linkage of Mab-PL-DTPA (IV), which was subsequently chelated with 111In to yield (V), which was the compound of interest. Indium-111-PL-DTPA (VI) and 111In-DTPA-MabTP41.2F(ab')2 (VII) also were prepared for control studies. Direct cell binding assay revealed the mean immunoreactivity of (V) to be 79.4% and that of (VII) to be 39.5%. In a biodistribution study on melanoma tumor-bearing athymic mice at 4, 24, and 48 hr postinjection, the tumor/blood and tumor/liver ratios at 48 hr were 11.6 and 1.2 for (V), compared to 3.7 and 0.13, respectively, with (VII). Thus, the PL configuration for radiolabeled antibodies seems to result in decreased hepatic accumulation and retained tumor activity. The findings suggest that further studies of this new compound are warranted.
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PMID:Reduced hepatic accumulation of radiolabeled monoclonal antibodies with indium-111-thioether-poly-L-lysine-DTPA-monoclonal antibody-TP41.2F(ab')2. 155 42

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.
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PMID:Characterization of antibody-chelator conjugates: determination of chelator content by terbium fluorescence titration. 190 6

To improve the tissue characterizing information obtained by MRI we examined 35 patients with 43 different intraocular lesions by applying Gadolinium-DTPA for the first time. Histology was available in seven cases. Twenty patients were diagnosed as having a malignant uveal melanoma, 2 had a melanoma of the ciliary body and the iris, 3 patients were found to have a naevus of the uvea and 3 patients suffered metastatic uveal infiltrates, 4 patients had a senile maculopathy and 10 patients had either a vitreal or a subretinal haemorrhage, 1 patient had an angioma and another a lymphoma of his vitreous. Ruthenium plaques were applied to 13 out of 20 melanoma patients. These patients were followed-up by MRI examinations at regular intervals after therapy. The pretherapeutic signals of melanotic melanomas were high before applying Gadolinium-DTPA and demonstrated a further increase after contrast enhancement. Following ruthenium therapy the drop of the precontrast signal was more pronounced than the postcontrast signal. In complicated clinical situations MRI offers additional information to enable the differentiation between intraocular tumors and haemorrhages.
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PMID:[Differential intraocular tumor diagnosis in MRI using gadolinium DTPA: value in comparison with other ophthalmologic examination procedures]. 204 26

The value of gadolinium-enhanced MRI in 30 patients with intraocular lesions has been evaluated. Seventeen patients had a uveal melanoma, two a ciliary body melanoma, three had uveal metastases, one lymphoma, four had senile macula degenerations, and three uveal nevi. Twelve of 17 patients with melanoma were followed up by MRI after ruthenium plaque therapy on 2-4 occasions. Melanomas showed high precontrast signal intensities and only a slight enhancement after intravenous Gd-DTPA was given. After ruthenium plaque therapy precontrast signal intensities (SI) decreased while a moderate signal increase on postcontrast scans was noted. Scars or tumor residues were better delineated on enhanced images. All other tumors than melanotic melanomas showed low SI on precontrast scans and a high signal increase after Gd-DTPA administration. Small amelanotic tumors were better delineated on postcontrast scans. In addition Gd-DTPA-enhanced MRI allowed differentiation between tumor and hemorrhage. No signal increase after Gd-DTPA application was seen in subretinal or vitreous hemorrhages of varying ages.
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PMID:Gadolinium-DTPA-enhanced MRI of intraocular tumors. 226 93

The effects of lipid composition on the relaxivity of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) entrapped in lipid vesicles has been examined for vesicles of different sizes composed of egg phosphatidylcholine and cholesterol in various molar ratios, as well as the stability of those same vesicles in human serum at 37 degrees C. It is found that the incorporation of cholesterol decreases the apparent relaxivity of the entrapped Gd-DTPA, concomitant with an increase in vesicle stability in serum. Cholesterol has little effect on relaxivity when incorporated at ratios up to 20 mole percent, but has an increasing effect at higher mole percentages. These results correlate with the known effects of cholesterol on the osmotic water permeability coefficients of various model membrane systems and suggest that it is the water flux across the vesicle bilayer that is limiting to the T1 relaxivity of the entrapped Gd-DTPA. The incorporation of up to 20 mole percent cholesterol has little effect on the stability of the vesicles in serum, whereas vesicles containing more than 20 mole percent cholesterol show greater increases in stability. It was also found that the stability of vesicles depends upon the size of the vesicles; smaller vesicles are less stable in human serum at 37 degrees C than larger vesicles.
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PMID:The effect of lipid composition on the relaxivity of Gd-DTPA entrapped in lipid vesicles of defined size. 230 54

Liposomes entrapping gadolinium-DTPA (Gd-DTPA) were synthesized from 60 mole percent egg phosphatidylcholine (EPC) and 40 mole percent cholesterol or EPC alone entrapping Gd-DTPA in diameters of 100 and 200 nm. Rats bearing Morris hepatoma in their flanks were imaged by MR pre- and post-contrast with free Gd-DTPA and liposomal Gd-DTPA for up to four hours after IV contrast. Comparison of images after free and liposomal Gd-DTPA showed dramatic differences in tumor and organ enhancement. Liposomal Gd-DTPA enhancement of tumor corresponded more closely to histologically proven vascularized portions of tumor than free Gd-DTPA. Hepatic enhancement was greater with liposomal than free Gd-DTPA and time course of liver, kidney and tumor enhancement was prolonged. The 100-nm EPC Gd-DTPA liposomes caused the greatest enhancement. Gd-DTPA liposomes may be useful as liver and blood pool contrast agents. By varying lipid composition and vesicle size, patterns of enhancement may be selectively modified.
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PMID:Liposomal Gd-DTPA: effect of encapsulation on enhancement of hepatoma model by MRI. 281 20

The bicyclic anhydride of DTPA-1-14C (BADTPA-1-14C) was synthesized and reacted with an antibody to human melanoma associated antigen (MAA) and with one to human class II major histocompatibility complex antigen (HLA-DR). DTPA-1-C incorporation per mole of anti MAA at molar ratios of 1:1 to 200:1 ranged from 0.5 to 25, while immunoreactivity ranged from 49 to 9%. With antibody to HLA-DR, results were similar. Anti MAA, but not anti HLA-DR, demonstrated polymerization upon conjugation. BADTPA-1-14C provides a convenient and accurate method for measuring the amount of DTPA in monoclonal antibody preparations and its effect on immunoreactivity.
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PMID:A method for direct quantification of the amount of DTPA in 111In monoclonal antibody preparations. 304 Jun 33

Polyethyleneimine or polylysines of differing molecular sizes were substituted with either EDTA or DTPA and then with succinic acid groups. These polymers were then reacted with the amino groups on myosin-specific monoclonal antibody or its Fab using a water soluble carbodiimide. The polymer-antibody complexes were capable of binding up to 150 di- or trivalent ions per mole (Mn++, Gd , or 111In ) without attendant loss of antigen binding. The polylysine derivatives of the intact antibody were rapidly cleared and sequestered in the liver, whereas the polylysine 14-kilodalton (kd) derivative of Fab was cleared from the circulation with minimal hepatic and kidney sequestration. This differed from the biodistribution of intact antimyosin or its Fab labeled with 111In via direct attachment of DTPA to the epsilon amino group of the lysyl residues. Applications in magnetic resonance and nuclear imaging are envisioned.
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PMID:Monoclonal antibody modification with chelate-linked high-molecular-weight polymers: major increases in polyvalent cation binding without loss of antigen binding. 311 49


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