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J Lowder

Publications and source records attributed to J Lowder.

14 recordsLinked to original sources
PubMed1999

Does acute volume overloading in the setting of left ventricular dysfunction and pulmonary hypertension affect the defibrillation threshold?

The impact of acute volume overload hemodynamics on the DFT with concurrent moderate left ventricular systolic dysfunction is unknown. Ten mongrel dogs (17.2 kg), using a crossover study design, each had baseline (study 1) hemodynamic, echocardiographic, and DFT measurements. These measurements were repeated after left ventricular dysfunction was induced using a norepinephrine (5 micrograms/kg per min) infusion (study 2). Hemodynamic and DFT parameters were obtained simulating acute heart failure by volume overload with an 0.9% normal saline infusion to an associated mean pulmonary capillary wedge pressure of > 19 mmHg (study 3). Numerous significant echocardiographic and hemodynamic parameters were noted when the animals from studies 1 and 2, 2 and 3, and 1 and 3 were compared. A significant difference in the DFT was observed only when study animals 1 and 3 were compared (P < 0.02). None of the dogs were hypoxemic at the time of the acute heart failure DFT. The mechanism of this finding remains unknown. This data would suggest that acute volume overload with associated left ventricular dysfunction does adversely affect the DFT in a canine model.

Acute Disease↗
PubMed1997

Lymphocyte subset analysis on frozen whole blood.

An approach to perform lymphocyte subset analysis on frozen-thawed whole blood (F/T WB) is described. WB from 24 human immunodeficiency virus type 1 (HIV-1) seropositive individuals and 21 controls was analyzed fresh and after frozen storage (with or without dimethyl sulfoxide) at -80 degrees C, in liquid nitrogen (LN2), and at -20 degrees C. Analysis of F/T WB utilized 3-color flow cytometry with CD45 and right angle light scatter gating. Absolute cell counts were obtained for 30 samples by using staining tubes containing internal bead standards [TruCount, Becton Dickinson Immunocytometry Systems (BDIS), San Jose, CA]. The mean difference between CD3+4+ percentages for F/T (-80 degrees C storage for up to 1 year) and fresh WB was less than -0.2% (95% limits +/-3%, P = 0.5) with 39 of 45 (87%) results falling within 2% of the fresh values (P = 0.74). Absolute CD3+4+ cell counts for F/T WB were generally lower than corresponding results for fresh aliquots (median difference was 33 cells/microl, P < 0.0001), but the results were highly correlated (r2 = 0.975, P < 0.0001). Results were more variable, although still highly correlated, for CD3+8+ cells, and with other freezing and storage conditions. It is concluded that lymphocyte subset analysis using F/T WB yields comparable results to fresh samples, which should prove useful for a number of practical applications.

Blood Preservation↗
PubMed1991

Selective activation of T cells in newly diagnosed insulin-dependent diabetic patients: evidence for heterogeneity of T cell receptor usage.

Cell surface phenotyping of 58 newly diagnosed diabetic children and 25 controls confirmed the presence of activated T cells, expressing HLA class II antigens or receptors for interleukin-2 (IL-2R, CD25) in the majority of the patients. Some of these cells putatively include those involved in islet cell destruction, as reported previously. Monoclonal antibodies recognizing three families of the variable regions of the beta chain (V beta) of the T cell receptor were used to determine the percentage of peripheral blood cells expressing those specific gene segment products. The number of the activated T cells from each V beta family was compared with that of the resting T cells of the same family in the patients and the controls. In 18 out of 58 (31%) of these patients there was evidence of oligoclonal proliferation of activated T cells as judged by marked increases in cells expressing a V beta family in the IL-2R+ T cell pool, compared with the total T cell pool. However, different V beta families were augmented in individual patients, indicating considerable heterogeneity of T cell activation in different patients. These results are in contrast to murine models of autoimmunity, where virtually monoclonal T cell activation, restricted to a single V beta family has been reported.

Adolescent↗
PubMed1991

Flow cytometric analysis of peripheral blood lymphocytes in ulcerative colitis and Crohn's disease.

Using two colour immunofluorescence with fluorescein isothiocyanate and phycoerythrin labelled monoclonal antibodies, multi-parameter flow cytometry was used to examine the antigenic characteristics of peripheral blood lymphocytes in whole blood of patients with ulcerative colitis and Crohn's disease who were not taking immunosuppressive drugs. The numbers of CD4+ and CD8+ lymphocytes in patients with ulcerative colitis and Crohn's disease remained unchanged so that the CD4/CD8 ratio was the same as that of normal control subjects. In Crohn's disease there were many activated T cells (CD3+, CD25+). Although natural killer cells in active Crohn's disease were lower than in normal control subjects, cytotoxic T lymphocytes, as defined by CD3+, CD16+, did not differ in patients with inflammatory bowel disease compared with normal control subjects. For B cell subsets, there were differences in Leu-1+ B cells, Leu-8+ B cells, Fc epsilon R+B cells (Leu-16+, Leu-20+), and activated B cells (Leu-12+, Leu-21+) between patients with inflammatory bowel disease and normal control subjects. These differences are compatible with local activation of B cells in the inflamed colon.

Adolescent↗
PubMed1989

High-dose thiotepa with autologous bone marrow transplantation for metastatic malignant melanoma: results of phase I and II studies of the North American Bone Marrow Transplantation Group.

We evaluated thiotepa in escalating dose in a broad phase I and II study using cryopreserved autologous bone marrow transplantation to assure hematopoietic recovery. Thiotepa was administered intravenously (IV) over two hours daily for three consecutive days followed in three to four days by marrow transplantation. The daily dose ranged from 60 to 525 mg/m2 (total dose, 180 to 1,575 mg/m2). A total of 71 patients with malignant melanoma were treated. Forty-three patients (61%) had received prior cytotoxic therapy and 28 were untreated. Sixty-two patients (87%) had melanoma disseminated to at least one visceral site, nine patients had skin and/or lymphatic metastases only. As of January 1, 1988 one patient was too early to be evaluated, 15 patients were inevaluable for tumor response, four patients had a complete response (CR), and 25 patients had a partial response (PR) to treatment. The response rates (95% confidence interval) for the 55 evaluable patients and for all 71 treated patients were 53% (40% to 65%) and 41% (30% to 53%), respectively. The median duration of response was 3 months, with a range of 1 to 31 + months. Three patients were alive and well without evidence of tumor more than 1 year after treatment. Analysis of patient subsets indicated that neither total dose, previous cytotoxic therapy, or sites of metastases influenced response rate. In this study, high-dose thiotepa has demonstrated a high response rate in patients with metastatic malignant melanoma with both PRs and CRs noted. Although most of the responses were not durable, 10% of the responses lasted more than 1 year. Future studies will evaluate additional methods for increasing the response rate and improving the duration of response.

Adult↗
PubMed1987

Quantitation and estimation of lymphocyte subsets in tissue sections. Comparison with flow cytometry.

A quantitation method for lymphocyte subsets in immunoperoxidase-stained frozen tissue sections was compared with flow cytometry in 23 cases of non-Hodgkin's lymphoma. Close correlations were obtained, demonstrating the accuracy of the technic. Weak intensity of fluorescence and fragility of the tumor cells during the fluorescence-activated cell sorter (FACS) analyses were the most likely explanations for a number of the discrepancies observed. The tissue quantitation method was precise, particularly at low values, where it was better than the FACS. A simpler and faster estimation method employing categories within 10 percentage units was also tested in this study; this method correlated as well with the FACS as the quantitation method and gave the best interobserver correlations.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Anti-idiotypes in B-cell tumor therapy.

Thirteen patients with B-cell lymphomas were treated with mouse monoclonal anti-idiotype antibodies. All but 1 of the patients in this study had received extensive prior treatment with conventional therapy for lymphoma. The treatment protocol initially included an escalating dose schedule which was intended to help us evaluate toxicity and pharmacokinetics and, eventually, to achieve appreciable levels of free mouse antibody in the circulation. The last 4 patients received substantial initial doses. Tumor sampling was performed before and during therapy for evaluation of tissue penetration by antibody. Patients received antibodies of gamma 1, 2a, or 2b isotype. None of the patients had serum paraproteins by routine clinical testing, but 6 had an idiotype protein detectable by a sensitive immunoassay at levels greater than 1 microgram/ml, two of which were greater than 200 micrograms/ml. These levels were temporarily reduced by plasma-pheresis. However, the presence of serum idiotype increased the requirement for mouse antibody to achieve tumor penetration. Another obstacle to treatment was immune response to mouse Ig that occurred in 5 of the 13 patients. Once an immune response had begun, further infusions of antibody failed to reach the tumor or induce tumor regression and were associated with toxicity. Our initial patient remains in an unmaintained complete remission 50 months after receiving antibody. Six of 12 additional patients have had objective remissions which also were clinically significant. However, these remissions were not complete. This therapy shows promise as an alternative modality for the treatment of B-cell lymphoma. We will need further studies to determine the mechanisms of the antitumor effect and to improve the clinical results.

Antibodies, Monoclonal↗
PubMed1985

Detection of B-cell lymphoma in peripheral blood by DNA hybridisation.

As an alternative to morphological identification of circulating neoplastic lymphocytes in the blood of patients with non-Hodgkin's lymphoma, DNA of peripheral blood lymphocytes was analysed for clonal immunoglobulin gene rearrangements in 29 patients with low-grade B-cell lymphomas. 76% of the patients showed clonal rearrangements of immunoglobulin genes in their blood, including 58% of those with no other evidence of disease. In seven patients from whom paired samples were available the rearranged bands found in the blood and in lymph-node biopsy specimens containing histologically confirmed lymphoma were identical. Detection of circulating lymphoma cells by use of tumour-specific anti-idiotype antibodies and cytofluorimetry showed complete agreement with the results of DNA analysis.

B-Lymphocytes↗
PubMed1985

Emergence of idiotype variants during treatment of B-cell lymphoma with anti-idiotype antibodies.

We studied two patients with malignant B-cell lymphoma that manifested resistance to the therapeutic effects of anti-idiotype antibody because of the emergence of subclones with changes in their immunoglobulin idiotypes. In both patients, tumor-cell populations arose that were unreactive with anti-idiotype antibody but that retained surface immunoglobulin. One of the patients had an additional subpopulation of tumor cells that had switched from mu to gamma heavy-chain expression. Study of the immunoglobulin genes in the tumors confirmed that the subpopulations were derived from the same original clone of neoplastic B cells in each patient. The available data suggest that the idiotypic variation observed was the result of somatic mutation in the variable region of the active immunoglobulin genes. The fact that such mutations became evident over a short time and in the context of a partial tumor response suggests that the antibody therapy exerted a strong selective force against tumor cells that expressed the idiotype determinant. Multiple anti-idiotype antibodies may therefore be needed to identify all cells of a malignant clone, and some patients may require treatment with more than one monoclonal antibody.

Adult↗
PubMed1985

Differences in "host infiltrates" among lymphoma patients treated with anti-idiotype antibodies: correlation with treatment response.

To correlate treatment responses with numbers and types of "host cell infiltrates," lymphoid tissues from 10 patients with low-grade B cell malignancies were stained before, during, and after anti-idiotype therapy with a panel of monoclonal antibodies applied to frozen sections. Tissue penetration by the anti-idiotype antibodies was confirmed in five patients by these immunoperoxidase methods. Large numbers of phenotypic T helper cells were the main component of the "host infiltrate" in most patients. Two patients showed a complete and a near-complete clinical remission, four others had partial responses, and four did not respond to therapy. The two patients that developed clinical remission demonstrated the largest number of T cells, T helper cells, TAC+ cells, Leu-7+ cells, and in general the smallest number of proliferating cells as measured by the Ki-67 antibody. Other major differences in host cells were not evident among the patients. These preliminary data suggest that the type and amount of "host infiltrate" in low-grade B cell lymphomas may predict which patients will respond to anti-idiotype therapy.

Animals↗
PubMed1985

A clinical trial of anti-idiotype therapy for B cell malignancy.

Eleven patients with B lymphocytic malignancy were treated with mouse monoclonal anti-idiotype antibodies. All but one of the patients in this study had received extensive prior treatment with conventional lymphoma therapy. All antibodies were prepared against, and uniquely reactive with, the patient's own tumor. Ten patients were treated with a single antibody, but one patient received three antibodies concurrently. The treatment protocol initially used an escalating dose schedule that was intended to evaluate toxicity, pharmacokinetics and, eventually, to achieve appreciable levels of free mouse antibody in the circulation. The last two patients received substantial initial doses. Tumor sampling was performed before and during therapy to evaluate tissue penetration by antibody. None of the patients had serum paraproteins by routine clinical testing, but six had idiotype protein detectable by a sensitive immunoassay at levels greater than 1 microgram/mL, two of which were greater than 200 micrograms/mL. Plasmapheresis was capable of reducing these levels temporarily. However, the presence of serum idiotype increased the requirement for mouse antibody to achieve tumor penetration. Another obstacle to treatment was immune response to mouse Ig, which occurred in five of the 11 patients. Once an immune response had begun, further infusions of antibody were not capable of reaching the tumor or inducing tumor regression and were associated with toxicity. Our initial patient remains in an unmaintained complete remission 42 months after receiving antibody. Five of ten additional patients have had objective remissions that were also clinically significant. However, these remissions were not complete and were of relatively short duration. This therapy shows promise as an alternative modality for the treatment of B cell malignancy. Further study will be needed to determine the mechanisms of the antitumor effect and to improve the clinical results.

Adult↗
PubMedDate not supplied

Innovations in quality.

To strengthen their operations many hospitals have embraced total quality management (TQM) strategies used by companies throughout the world. California Hospitals examines how some of these hospitals have used TQM to improve clinical outcomes, cut costs, boost staff morale and increase patient satisfaction.

California↗