Biomedical subjects

R Delellis

Publications and source records attributed to R Delellis.

5 recordsLinked to original sources

PubMed1992

Crossreacting human lymphoma idiotypes.

We have examined an unselected series of 72 lymphomas of diverse histologies with a panel of mouse monoclonal antibodies specific for human B-lymphoma-derived Ig idiotypes (anti-ids) to determine the nature and extent of id/anti-id crossreactivity. The anti-id antibodies were prepared from Ig isolated from seven follicular center cell lymphomas by heterohybridoma technique. Thirty-six of 75 individual anti-ids obtained in this manner were further selected based on their reactivity with highly restricted or private idiotypic determinants. Twelve of the 72 (17%) lymphoma biopsies reacted with one or more of the 36 anti-ids that detect private determinants. A pool consisting of five individual antibodies would have detected 11 of the 12 crossreacting tumors. Staining of tumor cell populations was homogeneous in the positive cases, suggesting uniform idiotype expression. If there was a segregated staining pattern, it was generally related to the presence of CD3+ T cells in the section. These follicular center cell-derived anti-ids cross-reacted with follicular center cell tumors of all histologic grades with frequencies ranging from 13% to 50%. The structural basis for the crossreactivity of our lymphoma-derived private anti-ids is as yet not known. However, the reactivity of certain anti-ids with both kappa- and lambda-expressing tumors suggests a biased use of V gene segments in these crossreactive clones that is probably related to the VH gene. These data suggest the possibility that lymphoma may develop in a highly restricted pool of normal differentiated B cells or in B-cell subsets that express a limited repertoire of unmutated VH gene segments.

Animals↗

PubMed1987

The neuropeptide-synthesizing rat 44-2C cell line: regulation of peptide synthesis, secretion, 3,'5'-cyclic adenosine monophosphate efflux, and adenylate cyclase activation.

We established in culture a clonal strain (44-2C) which produces calcitonin (CT), CT gene-related peptide, neurotensin (NT), and somatostatin (SS). A compendium of experimental data detailing for this strain the differential regulation of NT, CT, and SS synthesis and secretion, adenylate cyclase activation, and cAMP efflux is presented herein. The effects of hypophysiotropic peptides, brain-gut peptides, and catecholamines are described in detail. The effects of steroid hormones, and in particular, that of the synthetic glucocorticoid, dexamethasone, are presented. The effect(s) of basic bovine fibroblast growth factor are also described. In 44-2C cells basic fibroblast growth factor selectively regulates the synthesis and secretion of CT, NT, SS, and cAMP. Moreover, basic fibroblast growth factor enhances the responsiveness of 44-2C cells to neurosecretory peptides such as rat hypothalamic GRF. We conclude that the 44-2C cells are a useful in vitro tool to study the cellular mechanism(s) controlling the differential synthesis and secretion of neuropeptides.

Adenylyl Cyclases↗

PubMed1986

Monoclonal antibody specific for an activated RAS protein.

Activated RAS transforming genes that encode proteins (p21s) with amino acid substitutions at positions 12, 13, or 61 have been detected in 10-20% of human neoplasms. This report describes a monoclonal antibody (DWP) raised against a synthetic peptide corresponding to amino acids 5-16 of a mutated RAS gene encoding Val instead of Gly at position 12. DWP reacted in competition assays with peptides containing Val or Cys at position 12, but did not react with peptides containing Gly, Arg, Ser, Ala, Asp, or Glu at position 12. Immunoblot analysis of transformed NIH cells and human carcinoma cell lines showed that DWP reacts specifically with activated RAS proteins containing Val at position 12 and not with normal p21s or p21s activated by other amino acid substitutions at positions 12 and 61. Immunohistochemical studies showed that DWP-labeled transformed NIH cells and human carcinoma cells contained p21s with either Val or Cys at position 12 but not normal or other activated p21s. In contrast to the specificity seen with human carcinoma cell lines, analysis of formalin-fixed, primary carcinoma specimens indicated that positive immunoperoxidase staining with DWP did not necessarily correlate with immunoblot and transfection assays for the presence of activated RAS proteins. Immunohistochemical studies did show, however, that DWP preferentially binds human carcinoma cells.

Amino Acid Sequence↗

PubMed1977

Thymoma and primary lymphoma of the small intestine.

A case or primary poorly differentiated lymphocytic lymphoma of the ileum in a patient previously found to have an epithelial thymoma is described. While the frequency of malignancies of many types is increased in patients with thymoma, malignant lymphomas represent the most commonly associated tumor type. Lymphomas in these patients may devleop as a result of defective immunologic surveillance, impaired immunoregulation in partially immuno-deficient hosts, or by immunostimulation. The intestinal origin of the tumor in this case suggests that it may have developed as a result of local stimulation of lymphoid tissues by an antigen or antigens present in the intestinal contents.

Humans↗

PubMedDate not supplied

Destruction of joint homografts. An experimental study.

The host synovium undergoes a striking transformation at about 26 weeks after joint homografting. Histologically the synovium invaded and destroyed the graft with which it came in contact, becoming markedly hypercellular; the infiltrate consisted mainly of plasma cells and lymphocytes. The synovium at this stage closely resembled a rheumatoid pannus. The cartilage in contact with this invasive synovium lost its staining qualities, failed to take up S-35, and was gradually destroyed. The mechanism causing this transformation remains unclear. It is postulated that these changes could be due to an inflammatory or immune response.

Animals↗