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229 results on '"Welt, S."'

4. Dispersal, not vicariance, explains the biogeographic origin of iguanas on Madagascar

Author

Welt S. Rachel and Raxworthy J. Christopher

Subjects
biology, Fossils, Ecology, Biogeography, Lizards, Iguanidae, biology.organism_classification, Gondwana, Opluridae, Iguanas, Madagascar, Genetics, Vicariance, Leiosauridae, Animals, Humans, Biological dispersal, Iguania, Molecular Biology, Phylogeny, Ecology, Evolution, Behavior and Systematics
Abstract

Lizards of the clade Iguanidae (sensu lato) are primarily a New World group. Thus, the remarkable presence of an endemic lineage of iguanas (family Opluridae) on the isolated Indian Ocean island of Madagascar has long been considered a biogeographic anomaly. Previous work attributed this disjunct extant distribution to: (1) vicariance at about 140-165 Ma, caused by the breakup of Gondwana and the separation of South America, Africa, and Madagascar (with subsequent extinction of iguanas on Africa, and potentially other Gondwanan landmasses), (2) vicariance at about 80-90 Ma, caused by the sundering of hypothesized land-bridge connections between South America, Antarctica, India, and Madagascar, or (3) long-distance overwater dispersal from South America to Madagascar. Each hypothesis has been supported with molecular divergence dating analyses, and thus the biogeographic origin of the Opluridae is not yet well resolved. Here we utilize genetic sequences of ultraconserved elements for all Iguania families and the majority of Iguanidae (s.l.) genera, and morphological data for extant and fossil taxa (used for divergence dating analyses), to produce the most comprehensive dataset applied to date to test these origin hypotheses. We find strong support for a sister relationship between the Opluridae (Madagascar) and Leiosauridae (South America). Divergence of the Opluridae from Leiosauridae is dated to between the late Cretaceous and mid-Paleogene, at time when Madagascar was already an island and was isolated from all other Gondwanan landmasses. Consequently, our results support a hypothesis of long-distance overwater dispersal of the Opluridae lineage, either directly from South America to Madagascar or potentially via Antarctica or Africa, leading to this radiation of iguanas in the Indian Ocean.

Published
2022

12. Phase I/II radioimmunotherapy trial with iodine 131 labeled monoclonal antibody G250 in metastatic renal cell carcinoma

Author

Welt, S., Williams, J.M., Deland, D., Nakhre, A., Oosterwijk, E., Gulec, S., Graham, M.C., Larson, S.M., and Old, L.J.

Subjects
Antibody mediated therapy in urological cancers, Gen- and immunotherapy of urological cancer, Gen- en immunotherapie van urologische kanker, Antilichaam gemedieerde therapie van urologische tumoren
Abstract

Item does not contain fulltext 11 p.

Published
1998

13. Short communication: A33scFv–cytosine deaminase: a recombinant protein construct for antibody-directed enzyme-prodrug therapy

Author

Deckert, P M, Renner, C, Cohen, L S, Jungbluth, A, Ritter, G, Bertino, J R, Old, L J, and Welt, S

Subjects
Membrane Glycoproteins, Recombinant Fusion Proteins, Immunoglobulin Variable Region, colon carcinoma, Nucleoside Deaminases, Polymerase Chain Reaction, Catalysis, Cytosine Deaminase, tumour targeting, Antigens, Neoplasm, Escherichia coli, Tumor Cells, Cultured, A33 antibody, Humans, Experimental Therapeutics, Immunoglobulin Fragments, antibody directed enzyme-producing therapy (ADEPT)
Abstract

A recombinant fusion protein of colon carcinoma binding A33 single chain antibody with cytosine deaminase displayed specific antigen binding and enzyme activity in surface plasmon resonance and is catalytic activity assay. In vitro, it selectively increased the toxicity of 5-FC to A33 antigen-positive cells by 300-fold, demonstrating the potency of this ADEPT strategy.

Published
2003

15. Relative therapeutic efficacy of (125)I- and (131)I-labeled monoclonal antibody A33 in a human colon cancer xenograft

Author

Ec, Barendswaard, Jl, Humm, Donoghue Ja, O., Sgouros G, Rd, Finn, Andrew Scott, Sm, Larson, and Welt S

Subjects
Iodine Radioisotopes, Mice, Membrane Glycoproteins, Colonic Neoplasms, Transplantation, Heterologous, Animals, Antibodies, Monoclonal, Humans, Mice, Nude, Female, Radioimmunotherapy, Radiopharmaceuticals, Neoplasm Transplantation
Abstract

A33, a monoclonal antibody that targets colon carcinomas, was labeled with (125)I or (131)I and the relative therapeutic efficacy of the 2 radiolabeled species was compared in a human colon cancer xenograft system.Nude mice bearing human SW1222 colon carcinoma xenografts were administered escalating activities of (125)I-A33 (9.25-148 MBq) or (131)I-A33 (0.925-18.5 MBq), (125)I- and (131)I-labeled control antibodies, unlabeled antibody, or no antibody. The effects of treatment were assessed using the endpoints of tumor growth delay and cure.Tumor growth delay increased with administered activity for all radiolabeled antibodies. Approximately 4.5 times more activity was required for (125)I-A33 to produce therapeutic effects that were equivalent to those of (131)I-A33. This ratio was approximately 7 for a nonspecific, noninternalizing isotype-matched, radiolabeled control antibody. Unlabeled A33 antibody had no effect on tumor growth. Approximately 10 times more activity of (125)I-A33 produced toxicity similar to that of (131)I-A33, and this ratio fell to approximately 6 for radiolabeled control antibody.Treatment with (125)I-A33 resulted in a relative therapeutic gain of approximately 2 compared with (131)I-A33 in this experimental system.

Published
2001

16. Immuno-PET of human colon xenograft- bearing BALB/c nude mice using 124I-CDR-grafted humanized A33 monoclonal antibody

Author

Ft, Lee, Hall C, Rigopoulos A, Zweit J, Pathmaraj K, Keefe Gj, O., Fe, Smyth, Welt S, Lj, Old, and Andrew Scott

Subjects
Mice, Inbred BALB C, Membrane Glycoproteins, Antibodies, Monoclonal, Mice, Nude, Recombinant Proteins, Iodine Radioisotopes, Mice, Radioimmunodetection, Antigens, Neoplasm, Animals, Humans, Female, Tissue Distribution, Colorectal Neoplasms, Neoplasm Transplantation, Tomography, Emission-Computed
Abstract

Radiolabeling monoclonal antibodies (mAbs) allows the evaluation of biodistribution of constructs in vivo through gamma camera imaging and also permits quantitation of mAb uptake in tumors through biopsy-based counting techniques. The quantitation of radiolabeled mAb uptake in cancer patients is complicated by the attenuation of gamma emissions of routinely used isotopes (e.g., 131I and 111In) and the spatial resolution and sensitivity of gamma cameras.We used the positron-emitting isotope 124I (half-life [T1/2] = 4.2 d) to label the recombinant humanized anti-colorectal cancer A33 antibody (huA33) and evaluated its biodistribution properties and PET imaging characteristics in BALB/c nude mice bearing SW1222 colorectal xenografts and control colon tumors.The immunoreactivity of radioconjugate was 78% as determined using the cell-binding Lindmo assay. The apparent association constant was found to be 2.2 x 10(9) M(-1), and the number of antibody binding sites per cell was 371,000. The radioconjugate was found to be stable in serum obtained from mice at various times after injection. Assuming a two-compartment model with a four-parameter fit of mean blood levels, the T1/2alpha was 1.5 h and the T1/2beta was 38.2 h. Excellent tumor uptake was obtained, with maximal uptake reaching 50.0 +/- 7.0 percentage injected dose per gram of tumor by 4 d after injection. Specificity of localization was shown by lack of uptake in control tumor. PET imaging detected antigen-positive tumor by 4 h after injection, and high-resolution images were obtained by 24 h after injection.In clinical trials using PET, huA33 labeled with 124I has potential for imaging and staging colon tumors and quantifying antibody uptake in colon tumors in vivo.

Published
2001

26. Additional studies of quasi-optimum feedback control techniques

Author

Friedland, B, Ling, C. K, Schilder, M, Thau, F. E, and Welt, S

Subjects
Electronics
Abstract

Quasi-optimal control technique for space vehicle attitude, bounded acceleration rendezvous in free space, and aircraft landing problem

Published
1968

38. Purification and Characterization of a Novel Restricted Antigen Expressed by Normal and Transformed Human Colonic Epithelium

Author

Catimel, B., primary, Ritter, G., additional, Welt, S., additional, Old, L.J., additional, Cohen, L., additional, Nerrie, M.A., additional, White, S.J., additional, Heath, J.K., additional, Demediuk, B., additional, Domagala, T., additional, Lee, F.T., additional, Scott, A.M., additional, Tu, G.F., additional, Ji, H., additional, Moritz, R.L., additional, Simpson, R.J., additional, Burgess, A.W., additional, and Nice, E.C., additional

Published
1996
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42. Preparation and preclinical evaluation of humanised A33 immunoconjugates for radioimmunotherapy

Author

King, DJ, primary, Antoniw, P, additional, Owens, RJ, additional, Adair, JR, additional, Haines, AMR, additional, Farnsworth, APH, additional, Finney, H, additional, Lawson, ADG, additional, Lyons, A, additional, Baker, TS, additional, Baldock, D, additional, Mackintosh, J, additional, Gofton, C, additional, Yarranton, GT, additional, McWilliams, W, additional, Shochat, D, additional, Leichner, PK, additional, Welt, S, additional, Old, LJ, additional, and Mountain, A, additional

Published
1995
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46. DEVELOPMENT OF AN EFFECTIVE ANTI-TUMOUR AGENT FROM THE MONOCLONAL ANTIBODY A33

Author

King, D. J., primary, Antoniw, P., additional, Turner, A., additional, Haines, A., additional, Farnsworth, A., additional, Adair, J., additional, Finney, H., additional, Lawson, A., additional, Lyons, A., additional, Owens, R. J., additional, Yarranton, G. T., additional, Shochat, D., additional, Welt, S., additional, and Old, L. J., additional

Published
1994
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