Long-term impact of previous breast biopsy on breast cancer screening modalities.

Approximately 80% of breast biopsies are performed for what proves to be a benign process. The patients who undergo these procedures should continue screening with breast physical examination and mammography. The long-term impact of breast biopsy on these screening modalities has not been well studied. We performed a prospective, follow-up evaluation in 63 patients who underwent needle localization biopsy with benign histology at our institution between 6 and 7 years ago. This evaluation consisted of a directed history, breast physical examination, and follow-up mammogram. Two patients (3%) had undergone mastectomy for an interval breast cancer; 17 others (28%) had undergone subsequent biopsies. No patient had changes on physical examination of the biopsy site. All mammograms were evaluated as normal or as having benign abnormalities. Excisional breast biopsy does not generally produce long-term changes affecting the interpretation of breast physical examination or mammography.

Wild-type p53 mediates apoptosis by E1A, which is inhibited by E1B.

Transformation of primary rodent cells by the adenovirus E1A and E1B oncogenes is a two-step process, where E1A-dependent induction of proliferation is coupled to E1B-dependent suppression of programmed cell death (apoptosis). The E1B gene encodes two distinct transforming proteins, the 19K and 55K proteins, both of which independently cooperate with E1A. E1B 19K or 55K protein, or the human Bcl-2 protein, functions to suppress apoptosis and thereby permits transformation with E1A. The E1B 55K protein blocks p53 tumor suppressor protein function, indicating that p53 may mediate apoptosis by E1A. In the mutant conformation, p53 blocked induction of apoptosis by E1A and efficiently cooperated with E1A to transform primary cells. When p53 was returned to the wild-type conformation, E1A+p53 transformants underwent cell death by apoptosis. This induction of apoptosis by conformational shift of p53 from the mutant to the wild-type form was inhibited by expression of the E1B 19K protein. Thus, the p53 protein may function as a tumor suppressor by initiating a cell suicide response to deregulation of growth control by E1A. E1B 19K and 55K proteins provide separate mechanisms that disable the cell suicide pathway of p53.

The adenovirus E1A proteins induce apoptosis, which is inhibited by the E1B 19-kDa and Bcl-2 proteins.

Cooperation between the adenovirus E1A and E1B oncogenes is required for transformation of primary quiescent rodent cells. Although expression of E1A alone will stimulate cell proliferation sufficient to initiate transformed focus formation, proliferation fails to be sustained and foci degenerate. Coexpression of either the 19-kDa or 55-kDa E1B oncoproteins with E1A permits high-frequency transformation by overcoming this cytotoxic response. Without E1B 19-kDa protein expression, however, transformants remain susceptible to induction of cell death. Rapid loss of viability is coincident with nucleolytic cleavage of DNA in intranucleosomal regions and chromatin condensation, hallmarks of programmed cell death (apoptosis). Furthermore, overexpression of a known suppressor of apoptosis, the Bcl-2 protooncogene, can rescue E1A-induced focus degeneration. Thus E1A-dependent stimulation of cell proliferation is accompanied by apoptosis and thereby insufficient to singly induce transformation. High-frequency transformation requires a second function encoded by the E1B 19-kDa protein to block apoptosis.

The 19-kilodalton adenovirus E1B transforming protein inhibits programmed cell death and prevents cytolysis by tumor necrosis factor alpha.

The adenovirus E1A and E1B proteins are required for transformation of primary rodent cells. When expressed in the absence of the 19,000-dalton (19K) E1B protein, however, the E1A proteins are acutely cytotoxic and induce host cell chromosomal DNA fragmentation and cytolysis, analogous to cells undergoing programmed cell death (apoptosis). E1A alone can efficiently initiate the formation of foci which subsequently undergo abortive transformation whereby stimulation of cell growth is counteracted by continual cell death. Cell lines with an immortalized growth potential eventually arise with low frequency. Coexpression of the E1B 19K protein with E1A is sufficient to overcome abortive transformation to produce high-frequency transformation. Like E1A, the tumoricidal cytokine tumor necrosis factor alpha (TNF-alpha) evokes a programmed cell death response in many tumor cell lines by inducing DNA fragmentation and cytolysis. Expression of the E1B 19K protein by viral infection, by transient expression, or in transformed cells completely and specifically blocks this TNF-alpha-induced DNA fragmentation and cell death. Cosegregation of 19K protein transforming activity with protection from TNF-alpha-mediated cytolysis demonstrates that both activities are likely the consequence of the same function of the protein. Therefore, we propose that by suppressing an intrinsic cell death mechanism activated by TNF-alpha or E1A, the E1B 19K protein enhances the transforming activity of E1A and enables adenovirus to evade TNF-alpha-dependent immune surveillance.

Antihistone antibodies in antinuclear antibody-positive juvenile arthritis.

The binding of antinuclear antibody-positive juvenile arthritis (JA) sera to bovine thymus histones H1, H2A, H2B, H3, and H4 was studied by an enzyme-linked immunosorbent assay. Seventy-five percent of the JA patients tested positive for at least 1 antibody specificity. Antihistone antibodies were predominantly IgM, while IgG antibodies were less common and were restricted to histones H1 or H3. In the group of patients with JA of pauciarticular onset, antihistone antibodies were significantly more elevated in patients with past or present uveitis than in patients without a history of uveitis. Anti-H1 antibodies in JA patients were found to react mostly with determinants located in the carboxyl-terminal domain of the H1 molecule. Sera were also reactive with human histone H1(0) or chicken histone H5, which are H1 variants found only in nondividing cells.

Specificities of IgM and IgG anti-histone H1 autoantibodies in autoimmune mice.

Autoantibodies to histone H1 represent the most common specificity among anti-histone autoantibodies in systemic autoimmune diseases. Here we analyse anti-H1 autoantibodies in mice from the following autoimmune strains: MRL/Mp-lpr/lpr, NZB and NZB x NZW/F1. Autoantibodies of the IgM isotype bind predominantly to epitopes located in the COOH-terminal domain of the H1 molecule, whereas IgG autoantibodies in the MRL/Mp-lpr/lpr and NZB strains also recognize epitopes requiring the integrity of both the COOH-terminal and the central globular domains of H1. In both of these strains, the titre of these IgG anti-H1 antibodies rises during the course of the disease. The importance of three-dimensional structure of histone H1 was attested by a significant decrease in IgG binding after cleavage of the H1 molecule within the folded globular domain. The binding of these sera to H1 variants from various species was also investigated and a strong binding of MRL/Mp-lpr/lpr sera to certain phylogenetically distant histone H1 variant molecules (sea-urchin sperm H1 and chicken erythrocyte H5) was observed. This cross-reacting binding can be explained by the presence in MRL/Mp-lpr/lpr sera of autoantibodies to H1(0), a variant found in non-dividing cells and exhibiting sequence homologies to the above mentioned variants. The significance and the possible implications of these data for the pathogenesis of autoimmunity are discussed.

Rat monoclonal antibodies to murine IgM determinants: application to antibody purification.

Two monoclonal rat antibodies (RAM11 and RAM12) were raised against mouse IgM antibodies. These 2 antibodies were isotype-specific since they bound murine IgM but not IgG or IgA antibodies; moreover, sera from mouse strains possessing different allotypic determinants inhibited the binding of RAM11 and RAM12. Both antibodies can be readily purified from culture supernatants on protein G-agarose (but not on protein A-agarose). After coupling to Sepharose 4B, RAM11 provided a useful affinity chromatography support for the purification of murine IgM antibodies from biological fluids.

Syngeneic anti-idiotype monoclonal antibodies to murine anticarcinoembryonic antigen monoclonal antibodies.

BALB/c mice were immunized with either NP-3 or NP-4, two anticarcinoembryonic antigen murine monoclonal antibodies. Each animal produced anti-idiotype antibodies to the corresponding immunogen and no cross-reactivity between anti-NP-3 sera and anti-NP-4 sera was detected. Hybridomas were produced from these animals and two IgG1 anti-idiotype monoclonal antibodies were obtained: CM1 specific for NP-3 and CM11 specific for NP-4. CM1 and CM11 recognized determinants located within the antibody-combining site, since each anti-idiotype antibody inhibited the binding between the corresponding idiotype and carcinoembryonic antigens. Using an immunoblotting technique, neither CM1 nor CM11 reacted with isolated heavy or light chains of NP-3 or NP-4, whereas binding was observed with the intact molecule. This observation indicates that CM1 and CM11 are directed against conformational idiotypes resulting from the association of the variable regions of the heavy and light chains. Taken together, these results suggest that CM1 and CM11 might bear internal images of carcinoembryonic antigen epitopes, and that they are potential candidates as idiotype vaccines against colorectal tumors.