Biomedical subjects
Publications and source records attributed to K C Anderson.
A 74-year-old woman with mild dementia became disoriented and developed paranoid delusions when treated with low-dose propranolol. There was no evidence of cardiovascular instability, and the symptoms resolved within a week. Rechallenge with propranolol led to a recurrence of mental status changes.
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Fewer than 25 cases of myocardial involvement with the Mucoraceae have been reported. We present a diabetic patient with recurrent ketoacidosis and staphylococcal septicemia whose demise was accelerated by unsuspected left atrial mural endocardial mucormycosis.
Apoptosis is the primary means by which most radio- and chemotherapy modalities kill cancer cells, and abnormalities in the apoptotic pathways may contribute to disease pathogenesis of cancer. Multiple Myeloma (MM) is a hematological malignancy which will affect 14,000 new individuals in the United States in 2001 and remains irreversibly fatal despite all available therapies. The current review focuses on the studies of apoptotic and survival signaling pathways in MM cells, which have both identified novel apoptotic and anti-apoptotic proteins and provided targets for novel therapeutics.
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Thirty-two patients with documented Eales' disease who have been followed-up at Johns Hopkins Hospital for periods of as long as 37 years were investigated. The previously reported association of Eales' disease with tuberculoprotein hypersensitivity was confirmed in 10 of 21 patients tested. For the first time, associated vestibuloauditory dysfunction is described. The previously reported association with multiple sclerosis was not confirmed. Eales' disease is a specific vasculopathy that can affect both the retinal and vestibuloauditory circulations. Patients with suspected Eales' disease should also be examined to rule out other diseases such as diabetes, sarcoidosis, and connective tissue diseases including systemic lupus erythematosus. This can be done by obtaining such tests as fasting blood glucose, chest radiograph, erythrocyte sedimentation rate, antinuclear antibody, rheumatoid factor, and LE cell preparation. Tuberculoprotein sensitivity status should be ascertained and active tuberculosis should be ruled out. The patient should be questioned regarding hearing or balance problems, and if a history suggestive of abnormalities is elicited, referral for vestibuloauditory function testing should be made.
The anti-CD20 chimeric monoclonal antibody rituximab (Rituxan) is used to treat patients with various B-cell tumors, including patients with plasma cell dyscrasias who have CD20+ disease. Many patients with CD20+ disease have either primary unresponsive disease or progress after initially responding to rituximab; therefore, understanding how tumor cells are, or become, resistant to rituximab is of clinical relevance. In this report, we determined whether tumor cells express antigens that block complement-mediated lysis or antibody-dependent cell-mediated cytotoxicity (ADCC) and thereby contribute to rituximab resistance. We demonstrate that expression of the complement regulator CD59 is associated with resistance to rituximab-mediated complement lysis of multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL) cell lines. Moreover, neutralization of CD59 using a blocking monoclonal antibody reversed resistance to rituximab-mediated complement lysis of CD20++ CD59++ ARH-77 MM cells. In addition, we demonstrate the presence of CD59 and rituximab binding on viable tumor cells from patients with MM and Waldenstrom's macroglobulinemia with progressive disease despite rituximab therapy. Last, we also examined MM and NHL B-cell lines, as well as patient tumor cells, for the expression of other antigens that may have a role in blocking ADCC activity, such as Fas ligand (FasL), MUCI, or TRAIL. FasL, MUC1, and/or TRAIL were coexpressed with complement regulators on many of these cells. These studies therefore show that complement regulators, particularly CD59 and antigens that may block ADCC, are present on various B-cell tumors and associated with rituximab resistance in patients. A prospective, clinical study is assessing the role of these antigens in mediating rituximab resistance.
Waldenstrom's macroglobulinemia (WM, lymphoplasmacytic lymphoma) is a B-cell lymphoproliferative disorder in which CD20 is expressed on tumor cells from most patients. Several small studies have suggested a benefit from the anti-CD20 monoclonal antibody rituximab (Rituxan, MabThera) in patients with WM. In this retrospective study, we examined the outcome of 30 previously unreported patients with WM who received treatment with single-agent rituximab (median age 60; range 32-83 years old). The median number of prior treatments for these patients was 1 (range 0-6), and 14 patients (47%) received a nucleoside analogue before rituximab therapy. Patients received a median of 4.0 (1-11.3) infusions of rituximab (375 mg/m2). Three patients received steroids with their infusions for prophylaxis of rituximab-related infusion syndrome. Overall, treatment was well tolerated. Median immunoglobulin M (IgM) levels for all patients declined from 2,403 mg/dL (range 720-7639 mg/dL) to 1,525 mg/dL (range 177-5,063 mg/dL) after rituximab therapy (p = 0.001), with 8 of 30 (27%) and 18 of 30 (60%) patients demonstrating >50% and >25% decline in IgM, respectively. Median bone marrow lymphoplasmacytic (BM LPC) cell involvement declined from 60% (range 5-90%) to 15% (range 0-80%) for 17 patients for whom pre- and post-BM biopsies were performed (p < 0.001). Moreover, 19 of 30 (63%) and 15 of 30 (50%) patients had an increase in their hematocrit (HCT) and platelet (PLT) counts, respectively. Before rituximab therapy, 7 of 30 (23.3%) patients were either transfusion or erythropoietin dependent, whereas only 1/30 (3.3%) patients required transfusions (no erythropoietin) after rituximab. Overall responses after treatment with rituximab were as follows: 8 (27%) and 10 (33%) of the patients achieved a partial (PR) and a minor (MR) response, respectively, and an additional 9 (30%) of patients demonstrated stable disease (SD). No patients attained a complete response. The median time to treatment failure for responding (PR and MR) patients was 8.0 months (mean 8.4: range 3-20+ months), and 5.0 months (mean 6.1; range 3-12+ months) for patients with SD. These studies therefore demonstrate that rituximab is an active agent in WM. Marked increases in HCT and PLT counts were noted for most patients, including patients with WM who had MR or SD. A prospective clinical trial to more completely define the benefit of single-agent rituximab in patients with WM has been initiated by many of our centers.
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Recent advances in our understanding of the molecular regulation of myeloma cells suggest novel strategies for treating multiple myeloma. Some myeloma cells express a 69 kD variant of Ku86, a heterodimer subunit that is essential for double-stranded DNA break repair. Presence of the variant impairs DNA repair; therefore normal Ku86 in myeloma cells confers resistance to therapy and may represent a therapeutic target. The upregulation of NF-kappaB-dependent interleukin-6 (IL-6) transcription and secretion that occurs following adhesion of myeloma cells to bone marrow stromal cells (BMSCs) may serve as a potential therapeutic target, as IL-6 is a growth and survival factor for myeloma cells. Accordingly, proteasome inhibitors inhibit activation of NF-kappaB and induce apoptosis of myeloma cells; they also inhibit the NF-kappaB-dependent up-regulation of IL-6 in BMSCs and related paracrine growth of adherent tumor cells. Therapeutic strategies may also target the mitogen-activated protein kinase (MAPK) pathway that is thought to mediate the IL-6-induced proliferation of myeloma cells. Vascular endothelial growth factor (VEGF) is also upregulated by adhesion of myeloma cells to BMSCs and may serve as a growth and/or survival factor for myeloma cells; preliminary studies suggest that VEGF receptor inhibitors may block proliferation of tumor cells. Thalidomide was recently used successfully to treat myeloma in patients whose disease was refractory to conventional treatment. An enhanced understanding of the mechanisms of action of thalidomide may result in the development of analogues with enhanced potency and fewer side effects. The potential mechanisms of action of thalidomide are reviewed, including antiangiogenic effects; direct effects of thalidomide on the growth and survival of myeloma cells and BMSCs; modulation of adhesive interactions; and regulation of secretion and bioactivity of cytokines. Immune-based strategies for treating multiple myeloma are also reviewed. Therapeutic obstacles include excessive toxicity after allografting, contaminating tumor cells in autografts, and the persistence of minimal residual disease (MRD) after high-dose therapy followed by allogenic or autologous stem cell transplantation. Allografting can be performed safely in myeloma, donor lymphocyte infusions (DLI) may effectively treat relapsed myeloma post allografting; and use of CD4+ T cell-enriched DLI may reduce the risk of graft-versus-host disease. Treatment with autografting is frequently compromised by MRD in the autograft and in the patient post myeloablative therapy. Adenoviral purging prior to autotransplantation and in vivo and ex vivo stimulation of autoimmune cells are discussed as potential approaches to address these problems.
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