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Biomedical subjects

D E Lewis

Publications and source records attributed to D E Lewis.

At least 127 records · Page 7Linked to original sources
PubMed1986

Influenza virus infection induces functional alterations in peripheral blood lymphocytes.

This report describes alterations in functional responses to lectin-induced stimulation of peripheral blood lymphocytes and in the natural killer cell (NKC) activity, of college students, obtained during an outbreak of influenza A/Philippines/2/82(H3N2) virus infection. These results are compared with similar observations in college students with an acute, febrile, noninfluenzal respiratory illness that occurred during the same outbreak. The lymphopenia typical of influenza during acute illness was shown to be due to a reduction in both T and B cells without alteration in the CD4:CD8 ratio. In addition, phytohemagglutinin and concanavalin A responses were reduced and NKC activity was increased, while pokeweed mitogen reactivity was unaltered at the time of admission to the study. Patients with noninfluenzal illness showed early polymorphonuclear leukocytosis and a similar lymphopenia. Lymphocyte functions were virtually unchanged during acute illness in noninfluenza patients. The relatively specific alterations in lymphocyte responses to lectin-induced stimulation in influenza patients may indicate that the peripheral T cells are incapable of activation via the CD3 or CD2 activation pathways. In addition, increased NKC activity in the periphery may be reflective of increased NKC activity in the lung. Influenza-infected individuals with higher NKC activity at the time of admission to the study also took longer to recover. Finally, the early lymphopenia and the later neutropenia in the influenza-infected patient may represent migration of these cells from the circulation to the infected respiratory tract as a consequence of infection.

Concanavalin A↗
PubMed1986

Monoclonal anti-actin antibody recognizes a surface molecule on normal and transformed human B lymphocytes: expression varies with phase of cell cycle.

A monoclonal anti-actin antibody, 2C9, was used to study the distribution of an actin-like cell-surface antigen (hereafter termed actin) on a lymphoblastoid cell line LA350 and on human peripheral blood lymphocytes. It was determined that 8-40% of LA350 cells and 3-15% of peripheral blood lymphocytes from healthy donors stain specifically with 2C9, almost exclusively on IgM-positive cells. Treatment of cells with 2C9 prior to incubation caused cell-surface actin to first patch and then to cap. Treatment of cells with nonspecific protease caused a loss of surface actin, with reexpression of the marker after 8-12 hr. The expression of LA350 surface actin also increased with DNA synthesis and was demonstrated to be maximal during late G1/early S phase. Thus, this antigen may be a sensitive marker for activated lymphocytes. These studies contribute to our understanding of the expression and distribution of actin-like membrane proteins that may participate in regulatory signals mediated by anti-actin antibody.

Actins↗
PubMed1986

Proliferative signals for suppressor T cells. Helper cells stimulated with pokeweed mitogen in vitro produce a suppressor cell growth factor.

To define molecular signals elaborated by inducer populations supporting growth or differentiation of T8+ cells, we collected supernatants of pokeweed mitogen (PWM)-stimulated cultures depleted of T8+ cells. When added to purified T8+ cells, these supernatants caused significant proliferation. PWM plus interleukin 2 (IL-2) in amounts equivalent to those in the supernatant could not reconstitute the response caused by the supernatant. T8+ cells activated by supernatants obtained from PWM-pulsed T4+ cells suppressed fresh PWM cultures. Although exhibiting little proliferation, T8+ cells cultured for 6 d in PWM plus IL-2 still suppressed a fresh PWM response. The supernatants therefore contain an additional T suppressor cell growth factor (TsGF). Elaboration of TsGF required radiosensitive T4+Leu8+ cells. Molecular weight determination by high performance liquid chromatography gave a single peak of TsGF activity at approximately 8,000. Finally, whereas TsGF in the absence of IL-2 could not support the proliferation of T suppressor cells, it did cause T8+ cells to become strongly IL-2 receptor-positive.

Antibodies, Monoclonal↗
PubMed1985

Epstein-Barr virus-associated B-cell proliferations of diverse clonal origins after bone marrow transplantation in a 12-year-old patient with severe combined immunodeficiency.

A 12-year-old boy with severe combined immunodeficiency who had been kept in a gnotobiotic environment since birth received bone marrow from a histoincompatible sibling in an attempt to reconstitute immunologic function. To prevent graft versus host disease, the donor's marrow was treated in vitro with monoclonal antibody and complement to remove alloreactive T cells. Eighty days after transplantation, the patient had a systemic illness characterized by fever, thrombocytopenia, gastrointestinal pain, and bleeding; he died on the 124th post-transplantation day. Postmortem examination revealed multiple tumor-like B-cell proliferations, recipient in origin, in numerous organs. Epstein-Barr virus (EBV) was isolated from the patient's pharyngeal secretions; EBV nuclear antigen was found in spontaneously transformed peripheral-blood lymphocytes, inflammatory cells from peritoneal fluid, and bone marrow cells; and EBV genomes were discovered in all tumor tissues. The donor's serum showed evidence of past EBV infection. Analysis of cellular immunoglobulin and immunoglobulin gene DNA from the tumors indicated both monoclonal and oligoclonal B-cell proliferations. These findings provide evidence for the evolution of EBV-induced polyclonal activation of B cells to oligoclonal B-cell proliferation and finally to monoclonal B-cell lymphoma.

B-Lymphocytes↗
PubMed1985

Multiparameter analysis of human lymphocyte subpopulations using flow cytometry.

This review has emphasized several recent advances in our understanding of human lymphocyte biology made possible by mAbs that recognize specific functional subpopulations of lymphocytes, coupled with multiparameter flow-cytometric analysis. In the last 3 years, both the T4+ and T8+ subsets of T cells have been further divided according to function and appearance of specific cell surface antigens. In addition, subpopulations of NK cells with different maturation states and B cells with distinct functional abilities have been discovered. Multiparameter flow-cytometric analysis of lymphocyte subpopulations can provide clues to the pathogenetic mechanisms of immune disorders, as has been demonstrated in AIDS patients and children with JRA. The use of multiparameter flow-cytometric analysis to study human immune responses in vitro has enabled a clearer understanding of the complex lymphoid interactions and, as we believe, may play an important role in the analysis of immune-associated disease processes.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Spontaneous antiidiotypic antibodies to the NZB Coombs autoantibody.

We have further investigated the phenomenon of spontaneous anti-(Coombs) antiidiotypic antibodies in the F1 hybrids of New Zealand black (NZB) and CBA mice. These mice show an age-related increase in incidence of such antiidiotype during the first year of life. There is no difference between males and females in the occurrence of antiidiotype. Reciprocal hybrids are both affected, so that maternal influence from the NZB strain is not critical. The antiidiotype also occurs in spite of the xid gene. We have so far detected such spontaneous antiidiotype only in (CBA X NZB)F1 hybrids and not in hybrids of NZB with two other strains or in a variety of recombinant inbred strains between NZB and C58. Our results to data suggest extensive shared idiotypy among NZB mice and a limited number of total idiotypes.

Aging↗
PubMed1984

Enzymatic and nonenzymatic hydrolysis of D,L-dipivefrin.

D,L-dipivefrin hydrochloride was administered bilaterally to rabbit eyes five or 150 minutes after unilateral application of a cholinesterase inhibitor. Aqueous humor levels of D,L-epinephrine, measured 30 minutes later by high-performance liquid chromatography, were not significantly different in the two eyes. Nonenzymatic conversion of D,L-dipivefrin to D,L-epinephrine was measured in tissue-free (pH 7.4) solutions; after three hours less than 1% of D,L-dipivefrin became D,L-epinephrine. Homogenates of corneal epithelium were 16 times more effective in converting D,L-dipivefrin to D,L-epinephrine than after heat-inactivation. The ocular hypotension produced by 0.25% D,L-dipivefrin eyedrops was unaffected by prior administration of 0.25% echothiophate iodide eyedrops provided the D,L-dipivefrin was administered after the echothiophate-induced ocular hypertensive phase. It was concluded that D,L-dipivefrin was converted to D,L-epinephrine in vivo primarily by enzymatic hydrolysis and that cholinesterase inhibitors did not affect this conversion.

Animals↗
PubMed1984

Cytotoxic anti-T cell antibodies in children with juvenile rheumatoid arthritis.

The object of this investigation was to determine the prevalence of anti-T cell antibodies in 66 children with various connective tissue diseases. Anti-T cell antibodies were found in 43/44 juvenile rheumatoid arthritis (JRA) patients (mean cytotoxicity 15.0%) and in 10/10 children with systemic lupus erythematosus (mean cytotoxicity 20.0%), but in only 1/15 normal controls and in none of 12 children with other arthritides. There was no significant difference in mean percent cytotoxicity among the JRA subclasses. In the JRA patients, the percent cytotoxicity was positively correlated with the erythrocyte sedimentation rate (P = 0.01), but not with the presence or absence of rheumatoid factor, antinuclear antibodies, or immune complexes. The sera of 3 JRA patients repeatedly inhibited the stimulation of normal lymphocytes by mitogens and antigens by 47-99% (measured by the incorporation of 3H-thymidine into DNA) when added to the culture system in the first 24 hours; normal sera did not. Sera from patients with JRA have increased reactivity with mitogen-activated lymphocytes and T cells compared with unstimulated cells as determined by flow cytometry. The expression of the "JRA antigen" requires protein synthesis but not DNA synthesis or cell division. We conclude that the majority of patients with active JRA have cytotoxic anti-T cell antibodies and that in selected patients, these antibodies may play a role in regulation of the immune response.

Antibodies↗
PubMed1984

Physician assistants in primary care. Patient assignment and task delegation.

This paper reports a concurrent self-report study of 2,456 office encounters with physicians and/or physician assistants (PAs) in 16 primary care, private practices in Florida. Initial patient assignment to either a physician or PA varies according to demographic and visit-specific characteristics. Patients who are male, younger than 65 years, new patients, seeking help for acute problems, and those who are "walk-in" or "work-in" patients are more likely to be assigned to a PA. Among frequently performed procedures, physicians are more likely to perform the partial histories, partial physicals, and pelvic examinations, as well as counsel patients on diet and psychosocial problems. PAs are more likely to perform the complete physical examinations, record vital signs, conduct diagnostic tests, and perform therapeutic procedures (administer injections, change dressings, etc.). Most tasks performed by PAs receive supervision through chart review rather than direct oversight. The typical patient visit in a practice employing a PA involves the receipt of services from only one provider. Approximately 50% of patient services are performed by physicians only, while 35% of the services are performed solely by PAs, and 15% are performed by both. Most patients have received care from both the physician and the PA.

Age Factors↗
PubMed1983

Bacterial and fungal growth in intravenous fat emulsions.

Growth of bacterial and fungal organisms in i.v. fat emulsions was studied. A total of 81 isolates of 15 bacterial and fungal strains were used to inoculate (in test tubes) 10% soybean oil emulsion (Intralipid, Cutter Laboratories), 10% safflower oil emulsion (Liposyn, Abbott Laboratories), trypticase soya broth, and 0.9% sodium chloride at about 2500 organisms/ml. Duplicate samples and negative controls were prepared. Samples were handled under two procedures after inoculation: (1) initially refrigerated overnight, then stored at room temperature for 24 hours, and (2) stored only at room temperature for 24 hours. Samples were taken at 3, 7, and 24 hours after the samples were placed at room temperature, and colony counts were performed. Most organisms grew equally well in the fat emulsions and trypticase soya broth. Fungal strains grew more slowly than bacterial strains but reached equal numbers by 24 hours. Organisms grew quite slowly in sodium chloride, and negative controls showed no growth. These i.v. fat emulsions supported bacterial and fungal growth at the same level as trypticase soya broth.

Bacteria↗
PubMed1982

Monoclonal antibodies against rat immunoglobulin kappa chains.

Monoclonal antibodies directed against rat kappa light chains have been generated by immunizing SJL/J mice with soluble rat immunoglobulin, followed by fusion of immune spleen cells with the P3-X63-Ag8 myeloma cell line. Monoclonal antibodies from three of these hybridoma cell lines, MAR 18.5, 80.2, and 103.6, have been extensively characterized. MAR 18.5, 80.2, and 103.6 antibodies are of the gamma 2a kappa isotype, and bind strongly to protein A, allowing easy purification. Monoclonal antibody from clone 18.5 binds equally well to Ig of both RI-1a and RI-1b allotypes, whereas 80.2 and 103.6 antibodies selectively bind to RI-1b. These monoclonal antibodies can be FITC conjugated for use as a second antibody in indirect immunofluorescence assays, or radiolabeled for use in radio immunoassays requiring a specific antirat kappa antibody. The antiallotype specific monoclonal antibodies also may be of use in the study of rat immunoglobulin genetics.

Alleles↗
PubMed1981

Flow cytometry analysis of T cells and continuous T-cell lines from autoimmune MRL/l mice.

The study of spontaneous autoimmunity in mouse models affords an opportunity to determine the cellular basis of the immune dysregulation observed in this disease. Recently, a new mouse strain, MRL/Mp-Ipr/Ipr (MRL/l) has been developed which carries an autosomal recessive gene (lpr) that results in massive lymph node enlargement concomitant with the development of several autoantibodies. The interest in this strain lies in the possibility that the defect in T-cell regulation of the immune response is manifested at a different level from that in the NZB mouse. It has been reported that the proliferating population of lymphoid cells in the nodes of these mice are T cells, but that many of them are devoid of Lyt surface antigens. We have accordingly initiated several lines of research with these mice, including quantitative flow cytometry characterization of Lyt antigen expression of cells in the lymph nodes of the mice. In an approach to isolate and study the properties of these cells, we have also established continuous cell lines from the lymph node cells of MRL/l mice, using techniques similar to those used to establish continuous lines of antigen-activated cytotoxic T cells and helper T-cell populations.

Animals↗
PubMed1981

Monoclonal anti-erythrocyte auto-antibodies from unimmunized NZB mice.

In order to study the heterogeneity of the anti-erythrocyte auto-antibody response in NZB mice, we have developed hybridomas producing monoclonal auto-antibodies with anti-erythrocyte activity. These monoclonals were prepared by fusion of NZB splenocytes with the P3 X 63.Ag8 myeloma and were screened for activity by indirect immunofluorescence using flow cytometry. We have produced a variety of monoclonal anti-red cell auto-antibodies that have differing antigenic reactivities and immunoglobulin isotypes. Eleven monoclonal antibodies extensively studied thus far react with intact mouse erythrocytes, whereas only two of the eleven also cross react with sheep erythrocytes and bromelain treated mouse erythrocytes. These results suggest that the fusion pattern may represent the range of anti-red cell auto-antibodies found in the intact NZB mouse, with the exception of monoclonal auto-antibodies against cryptic red cell auto-antigens, which were not demonstrated in this initial fusion study.

Animals↗
PubMed1980

Biosynthesis of mammary glycoproteins. Partial characterization of the sequence for the assembly of lipid-linked saccharides.

Incubation of a membrane preparation from the lactating bovine mammary gland with UDP-[3H]GlcNAc, GDP-[14C]Man, and UDP-[3H]Glc results in the biosynthesis of 15 lipid-linked saccharides that differ from one another by a monosaccharide unit. Pulse and chase kinetics indicate that these glycolipids are related to one another as precursor products for the biosynthesis of asparagine-linked glycoproteins of this tissue. [Man-14C]- and [Man-14C, GlcNAc-3H]saccharides were prepared from corresponding glycolipids by mild acid hydrolysis. Following extensive purification by paper and gel filtration chromatography, structural characterization was conducted on tri-, tetra-, penta-, and undecasaccharides via size determination on calibrated columns of Bio-Gel P-2 and P-4, compositional analysis, exo- and endoglycosidase digestions, methylation, Smith degradation, and acetolysis. These structures were identified as: Man beta 1 leads to 4(3)GlcNAc beta 1 leads to 4(3)Glc-NAc, Man alpha 1 leads to 3Man beta 1 leads to 4(3)GlcNAc beta 1 leads to 4(3)GlcNAc, Man alpha 1 leads to 3(Man alpha 1 leads to 6)Man beta 1 leads to 4(3)Glc NAc beta 1 leads to 4(3)Glc-NAc, and Man alpha 1 leads to 2 Man alpha 1 leads to 2Man alpha 1 leads to 3(Man alpha 1 leads to 2Man alpha 1 leads to 6[Man alpha 1 leads to 2Man alpha 1 leads to 3]Man alpha 1 leads to 6)Man beta 1 leads to 4(3)GlcNAc beta 1 leads to 4(3)GlcNAc.

Animals↗