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Biomedical subjects

L D Stein

Publications and source records attributed to L D Stein.

46 records · Page 3Linked to original sources
PubMed1985

Benefit of intravenous IgG replacement in hypogammaglobulinemic patients with chronic sinopulmonary disease.

Seven patients with hypogammaglobulinemia and chronic sinopulmonary infections were treated with a preparation of intravenous gammaglobulin. In order to maintain levels of serum IgG at greater than 500 to 750 mg/dl four weeks after infusion, 0.6 g/kg was administered every month. Stable serum levels were achieved after three to eight months. After six to 12 months of this regimen, there was significant reduction in acute infections requiring hospitalization, amelioration of clinical and radiographic evidence of chronic maxillary sinusitis, and improvement in pulmonary symptoms and pulmonary function test results. The administration of increased amounts of IgG intravenously is of benefit in patients with chronic sinopulmonary infections.

Adolescent↗
PubMed1984

Guanosine triphosphate catabolism in purine nucleoside phosphorylase deficient human B lymphoblastoid cells.

GTP catabolism induced by sodium azide or deoxyglucose was studied in purine nucleoside phosphorylase (PNP) deficient human B lymphoblastoid cells. In PNP deficient cells, as in control cells, guanylate was both dephosphorylated and deaminated but dephosphorylation was the major pathway. Only nucleosides were excreted during GTP catabolism by PNP deficient cells and the main product was guanosine. The level of nucleoside excretion was largely affected by intracellular orthophosphate (Pi) level. In contrast, normal cells excreted nucleosides only at low Pi level while at high Pi levels, purine bases (guanine and hypoxanthine) were exclusively excreted. PNP deficiency had no effect on the extent of GMP deamination.

Azides↗
PubMed1984

Ecto-5'-nucleotidase. I. Expression in human normal and neoplastic lymphoid cell lines representing sequential stages of B-cell differentiation.

The possible association of ecto-5'-nucleotidase (5'-NT) with differentiation of B-cells was explored with the use of normal and neoplastic lymphoblastoid cell lines representing sequential stages of B-cell maturation. There was no relationship between patterns of enzyme expression in the cell lines and immunoglobulin (Ig) secretion, chromosome constitution, proliferative rate, cell volume, or the presence of B1 and B2 antigens. Pre-B-cell lines, which were negative for surface Ig or Ig secretion but positive for cytoplasmic mu-chains, showed the presence of 5'-NT, whereas 9 of 11 lymphoma cell lines, Burkitt's or non-Burkitt's type, both secreting and nonsecreting, did not exhibit enzyme activity. Four myeloma cell lines and 13 of 15 normal B-cell lines were positive for 5'-NT. These results suggested that 5'-NT was present in pre-B-cells and in some very early B-cells. 5'-NT usually disappeared from early and some intermediate B-cells and reappeared in mature B-cells and plasmacytoid cells.

5'-Nucleotidase↗
PubMed1984

Heterogeneity of the human phosphocholine-specific B cell repertoire.

We have utilized a highly efficient method of culturing small numbers of Epstein Barr virus (EBV)-infected cells to analyze the heterogeneity of human antibodies specific for phosphocholine (PC). Lymphocytes from peripheral blood or tonsils of individuals who had no evidence of recent pneumococcal infection were infected with EBV and cultured at limiting dilution. After correction for the cloning efficiency, between 1/1500 and 1/10,000 B cells produced specific anti-PC antibodies by our criteria. Examination of the heterogeneity of these antibodies revealed that most individuals had an overwhelming predominance of anti-PC antibodies with kappa-light chain. Fine specificity analysis of 39 monoclonal anti-PC antibodies demonstrated that the IgM antibodies examined displayed significant binding site diversity, whereas the IgA PC-specific clones were much less heterogeneous. In general, the human anti-PC antibodies had a much higher relative affinity (Krel) for choline and glycerophosphocholine than the murine antibody families. Through examination of the human PC-specific B cell repertoire we have drawn some interesting parallels with the well-defined murine clonotype families and have begun to dissect the human response to this naturally occurring antigenic determinant.

Adolescent↗
PubMed1983

Limiting dilution analysis of Epstein-Barr virus-induced immunoglobulin production.

The major goal of this work is to establish a culture system for the growth of human B lymphocytes at the single-cell level so that the immunoglobulin secreted by the clonal progeny of that cell can be analyzed. A method which involves culturing small numbers (1-1000) of lymphocytes, which have been infected with Epstein-Barr virus (EBV) prior to plating, in round-bottom microtiter plates is described. A feeder layer of irradiated (2500 R) umbilical cord blood lymphocytes to which phytohemagglutinin has been added was found to be optimal. Culture supernatants collected from 3 to 6 weeks postinfection are assayed for the production of IgG and IgM by radioimmunoassay in order to determine the overall cloning efficiency of the system. We have shown that up to 33% of surface Ig-positive cells produce detectable clones in this system. Umbilical cord blood cells are superior to T-cell and macrophage cell lines as feeder layers. Furthermore, culture supernatants from phytohemagglutinin-stimulated umbilical cord lymphocytes do not adequately replace these cells. We also observed that while most IgM-secreting clones continued to produce immunoglobulin during the 7-week time period analyzed, the majority of IgG-secreting clones had a relatively short half-life in vitro. This culture system allows us to examine a significant proportion of the human B-cell population and carry out studies on the frequency of specific antibody- and isotype-producing clones.

Adult↗
PubMed1983

Inhibition of leucocyte migration by stimulated mononuclear cell supernatants from patients with ischaemic heart disease.

Leucocyte migration inhibition in patients with ischaemic heart disease was evaluated as an assay for progressive myocardial damage. Abnormal results were observed in 50% of patients with ischaemic cardiac disease. The prevalence of abnormal leucocyte migration inhibition was unrelated to clinical presentation, extent of coronary artery disease, or degree of impairment of left ventricular function. Six of the eight patients with unstable angina pectoris and abnormal leucocyte migration inhibition developed life threatening cardiac complications in the follow-up period compared with five patients with unstable angina and normal tests who developed no complications. A similar association between abnormal leucocyte migration inhibition and complications was not observed in patients with angina pectoris or previous myocardial infarction. Thus, leucocyte migration inhibition may be useful as a prognostic marker in unstable angina and may be an important additional variable to identify a high risk subset.

Adult↗
PubMed1983

Patterns of isotype commitment in human B cells: limiting dilution analysis of Epstein Barr virus-infected cells.

The frequency of Epstein Barr virus- (EBV) inducible IgM, IgG, and IgA-secreting cells in human peripheral blood and tonsil was determined by performing limiting dilution experiments in suspension culture. We devised a method of propagating small numbers of EBV-infected B cells with irradiated umbilical cord blood cells as a feeder layer. Precursor cell frequencies can be derived from these experiments; we have shown by statistical analysis that they conform to the single hit model of the Poisson distribution. By using this technique, a significant percentage of surface immunoglobulin-bearing lymphocytes are activated to secrete immunoglobulin in vitro. On the average, 8 to 38% of B cells in peripheral blood and tonsil can be propagated and the secreted immunoglobulin from the clonal progeny can be analyzed. Neither the EBV immune status of the donor nor the source of the umbilical cord blood feeder layer could account for the variations in cloning efficiency observed among donors. A surprisingly high frequency of B cells secreted IgA in vitro and we have shown that a small proportion of B cell clones in tonsil and peripheral blood secrete both IgM and IgA during the 4-wk culture period. Other B cells, including all those that produce IgG, appear to be committed to the secretion of a single isotype. Thus, these studies establish methodology for the analysis of the secreted products of human B cells at the single cell level and demonstrate that the progeny of at least some clones can secrete more than one isotype in vitro.

Adult↗
PubMed1982

Modulation of chronic lymphocytic leukemia cells by phorbol ester: increase in Ia expression, IgM secretion and MLR stimulatory capacity.

When cultured with 12-O-tetradecanoylphorbol 13-acetate (TPA) at a concentration of 1.6 X 10(-7) M, chronic lymphocytic leukemia (CLL) cells differentiated into mature cells of B lineage and increased their expression of surface Ia antigens when compared with cells cultured in the absence of TPA. Concurrently, TPA enhanced the ability of CLL cells to stimulate in a mixed lymphocyte reaction (MLR). The events induced in vitro by TPA that are characteristic of B cell maturation included morphologic changes, reduction in surface immunoglobulin (Ig), appearance of cytoplasmic Ig, and secretion of IgM. The increase in Ia expression and the enhanced capacity to stimulate in an MLR after incubation with TPA might also be associated with maturation of the CLL cells. The changes induced in vitro by TPA in neoplastic B cells provide new information concerning the terminal events in normal B cell differentiation.

Aged↗