Michael N. Margolies

Malignant Seeding of the Tract after Thin-Needle Aspiration Biopsy

Fine-needle aspiration biopsy is an established technique for cytodiagnosis of malignant neoplasms, yielding a high rate of positive tissue with negligible local sequelae. The authors report the first instance known to them of needle tract seeding following this biopsy technique in a patient with an unresectable pancreatic carcinoma. Because of the rarity of this occurrence, the procedural indications remain unaltered.

Arteriography in the Management of Hemorrhage from Pelvic Fractures

Abstract Localization of the source of massive hemorrhage from pelvic fractures is not often made clinically, and the results of expectant management or of hypogastric artery ligation are frequentl...

Arteriographic Management of Hemorrhage Following Pelvic Fracture

Nine patients with massive pelvic hemorrhage were evaluated angiographically. In each case the site of bleeding was identified by pelvic aortography and hemostasis was produced by intra-arterial techniques. Embolization with autologous clotted blood was employed in 8 cases and in one patient bleeding was controlled by proximally occluding the hypogastric artery with an inflated Fogarty catheter balloon.

Isolation, characterization, and distribution of an unusual pancreatic human secretory protein.

An unusual protein was isolated from acid extracts of normal human pancreas and pancreatic secretion in the form of uniform 7-10-nm long single threads without visible axial periodicity or other structure, as seen in the electron microscope. It accounts for as much as 300 micrograms/ml in some pancreatic secretions as measured by specific radioimmunoassay. The protein undergoes a freely reversible, pH dependent, globule-fibril transformation, being stable in the fibril form between pH 5.4 and 9.2. The monomer at acid pH has an apparent molecular weight of approximately 14,000 and consists of a single polypeptide chain, the amino acid composition of which is rich in aromatic amino acids and lacks carbohydrate, fatty acid, and phosphate. The amino acid sequence of 45 residues from the amino terminus shows no homology with any other reported protein sequences other than that of the A chain of the bovine pancreas thread protein (reported elsewhere). A sensitive radioimmunoassay employing monoclonal antibodies against human pancreatic thread protein failed to detect the antigen in a wide range of human tissues other than pancreas, nor was the antigen measurable in normal human sera. Immunohistochemistry utilizing these antibodies revealed the antigen as a component of the cytoplasm of some but not all the pancreatic acinar cells. A physiologic function has not yet been determined for this protein.

Expression of a hybrid immunoglobulin-T cell receptor protein in transgenic mice

We have constructed a hybrid immunoglobulin (VDJH)-T cell receptor (C alpha) gene using the VDJH exon from a digoxin-specific antibody. This gene was used to make a line of transgenic mice. The hybrid VDJH-C alpha protein is expressed on a subset of T cells in these mice, and we have shown that it forms part of a functional TCR complex by the criteria of coprecipitation and comodulation of CD3 and TCR beta chain components and T cell activation with anti-idiotypic antibodies or digoxin. Furthermore, in cells expressing the hybrid protein, there is allelic exclusion of endogenous TCR alpha genes. We discuss the implications for the comparative structure of T cell receptors and immunoglobulins.

Use of o-phthalaldehyde to reduce background during automated Edman degradation

Background generated during the cleavage step of the Edman degradation is a major obstacle to extended automated amino acid sequencing. It was demonstrated recently by A. S. Bhown, J. C. Bennett, P. H. Morgan, and J. E. Mole (1981, Anal. Biochem. 112, 158-162) that introduction of fluorescamine into the spinning cup reduced background by blocking primary amino groups at cycles where a proline residue is at the exposed amino terminus. A convenient blocking reaction program using o-phthalaldehyde which can be intercalated into the sequencing format of an automated Beckman liquid-phase sequencer is presented. The advantages of o-phthalaldehyde in blocking of primary amines when proline is amino terminal arise from its stability in aqueous solution and the ease of programmed metering of delivery to the sequencer spinning cup. The blocking reaction proved successful not only in extending sequence analyses but also in the elimination of unwanted sequences in selected peptide mixtures without the necessity of purification of the target peptide.

Binding and structural diversity among high-affinity monoclonal anti-digoxin antibodies☆

High-affinity monoclonal antibodies specific for the cardiac glycoside digoxin provide a useful system for the study of structure-function relationships between antibody combining site and specific antigenic determinants. Fifteen high-affinity monoclonal anti-digoxin antibodies were produced when spleen cells from A/J mice immunized with digoxin coupled to human serum albumin (Dig-HSA) were fused with the non-secreting murine myeloma Sp2/0 cell line. Each subcloned hybridoma antibody was analyzed for affinity and specificity for structurally related cardiac glycosides by a radioimmunoassay based on the adsorption of free [3H]digoxin to dextran-coated charcoal. All of the anti-digoxin hybridoma proteins demonstrated high affinity constants ranging from 10(9) to 10(12) M-1. Using seven different analogs of digoxin, binding specificities of the monoclonal antibodies were assessed by inhibition radioimmunoassay. The 15 hybridomas produced from fusions involving five mice could be divided into eight sets on the basis of these binding specificities. Certain antibodies exhibit a preference for the aglycone portion of digoxin, while others are more specific for the tridigitoxose sugar moiety of digoxin. Monoclonal antibody H- and L-chains were subjected to N-terminal amino acid sequence analysis. The antibodies may be divided into several sequence homology sets for both H- and L-chains. In most instances, homologous heavy chains are associated with a set of homologous light chains. Homologous partial sequences, however, do not correlate with similar antigenic specificities and affinities for digoxin. Thus the fine specificity for antigen is not dependent on VH- and VL-encoded sequences alone. These data illustrate the broad diversity of the elicited response to a single hapten, even in inbred mice.

Structure and Specificity of the Anti-Digoxin Antibody 40-50

We determined the sequence, specificity for structurally related cardenolides, and three-dimensional structure of the anti-digoxin antibody 40-50 Fab in complex with ouabain. The 40-50 antibody does not share close sequence homology with other high-affinity anti-digoxin antibodies. Measurement of the binding constants of structurally distinct digoxin analogs indicated a well-defined specificity pattern also distinct from other anti-digoxin antibodies. The 40-50-ouabain Fab complex crystallizes in space group C2 with cell dimensions of a = 93.7 A, b = 84.8 A, c = 70.1 A, beta = 128.0 degrees. The structure of the complex was determined by X-ray crystallography and refined at a resolution of 2.7 A. The hapten is bound in a pocket extending as a groove from the center of the combining site across the light chain variable domain, with five of the six complementarity-determining regions involved in interactions with the hapten. Approximately three-quarters of the hapten surface area is buried in the complex; two hydrogen bonds are formed between the antibody and hapten. The surface area of the antibody combining site buried by ouabain is contributed equally by the light and heavy chain variable domains. Over half of the surface area buried on the Fab consists of the aromatic side-chains. The surface complementarity between hapten and antibody is sufficient to make the complex specific for only one lactone ring conformation in the hapten. The crystal structure of the 40-50-ouabain complex allows qualitative explanation of the observed fine specificities of 40-50, including that for the binding of haptens substituted at the 16 and 12 positions. Comparison of the crystal structures of 40-50 complexed with ouabain and the previously determined 26-10 anti-digoxin Fab complexed with digoxin, demonstrates that the antibodies bind these structurally related haptens in different orientations, consistent with their different fine specificities. These results demonstrate that the immune system can generate antibodies that provide diverse structural solutions to the binding of even small molecules.

Contribution of Antibody Heavy Chain CDR1 to Digoxin Binding Analyzed by Random Mutagenesis of Phage-displayed Fab 26-10

We constructed a bacteriophage-displayed library containing randomized mutations at H chain residues 30-35 of the anti-digoxin antibody 26-10 Fab to investigate sequence constraints necessary for high affinity binding in an antibody of known crystal structure. Phage were selected by panning against digoxin and three C-16-substituted analogues. All antigen-positive mutants selected using other analogues also bound digoxin. Among 73 antigen-positive clones, 26 different nucleotide sequences were found. The majority of Fabs had high affinity for digoxin (Ka ≥ 3.4 × 109M−1) despite wide sequence diversity. Two mutants displayed affinities 2- and 4-fold higher than the parental antibody. Analysis of the statistical distribution of sequences showed that highest affinity binding occurred with a restricted set of amino acid substitutions at positions H33-35. All clones save two retained the parental Asn-H35, which contacts hapten and hydrogen bonds to other binding site residues in the parental structure. Positions H30-32 display remarkable diversity, with 10-14 different substitutions for each residue, consistent with high affinity binding. Thus complementarity can be retained and even improved despite diversity in the conformation of the N-terminal portion of the H-CDR1 loop.

Structural diversity among anti-p-azophenylarsonate monoclonal antibodies from A/J mice: Comparison of Id− and Id+ sequences

Amino acid sequence analyses were carried out on monoclonal anti-p-azophenylarsonate antibodies isolated from the ascites of mice carrying cell lines obtained from the fusion of A/J splenic lymphocytes with the myeloma cell line Sp2/0–Ag14. The partial primary structures of both heavy and light chains from seven idiotype negative hybridoma proteins are compared to those of six idiotype positive molecules. Amino-terminal amino acid sequences (40–47 residues) of heavy chains from molecules bearing the major cross-reacting idiotype, IdCR, demonstrated 95% homology to each other. Similarly, aminoterminal sequences of IdCR+light chains were homologous to each other. However, sequence variations were evident in individual antibodies in both framework and complementarity-determining regions, suggesting that a large family of molecules accounts for the major cross-reacting idiotype, as previously reported (Marshak-Rothstein et al., 1980b). Heavy and light chains from seven IdCR-negative monoclonal antibodies were subjected to amino-terminal (37–48 residues) amino acid sequence analysis. Four heavy chains were blocked to Edman degradation, but could be sequenced after enzymatic removal of the amino-terminal pyrrolidone carboxylic acid residue. In comparison with IdCR-positive heavy chains, the IdCR-negative heavy chains demonstrate greater diversity in both framework and complementarity-determining regions, with several different subgroups represented in contrast to the results from pooled serum IdCR-positive antibodies (Capra et al., 1975). One of the seven IdCR-negative light chains was blocked. The sequences of the remaining IdCR-negative light chains exhibited marked variations in both framework and complementarity-determining regions, with different chain lengths in the first complementarity-determining region in several light chains. Comparisons between the amino-terminal sequences of IdCR-positive and IdCR-negative monoclonal antibodies suggest that specific sequences in the first complementarity-determining regions of both heavy and light chains are not sufficient to account for the major cross-reacting idiotype. The structural basis for IdCR in A/J mice is likely to be in other segments of the variable regions.