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Biomedical subjects

F Lee

Publications and source records attributed to F Lee.

At least 235 records · Page 13Linked to original sources
PubMed1988

Prostate cancer: comparison of transrectal US and digital rectal examination for screening.

The authors examined 784 self-referred men over age 60 years to compare clinical usefulness of transrectal ultrasound (US) and digital rectal examination in a screening program for prostate cancer. Biopsy was performed in 77 cases, 83% (64 of 77) for abnormalities detected with transrectal US and 38% (29 of 77) because of findings at digital examination. Twenty-two cancers were detected, 20 with transrectal US and ten at digital examination. Overall detection rate for prostate cancer with transrectal US was two times higher than that with digital examination (2.6% vs 1.3%). Sensitivity, specificity, and negative predictive value for transrectal US and digital examination were calculated for a range of prevalences (0.028-0.1543). Sensitivity was two times higher for transrectal US than for digital examination. Transrectal US demonstrated 100% (17 of 17) of tumors with the most favorable prognosis (less than or equal to 1.5 cm in diameter) compared with 41% (seven of 17) for digital examination. The authors conclude that transrectal US is more sensitive than digital examination in the detection of prostate cancer, and they advocate broader implementation and evaluation of transrectal US as a tool for early detection.

Aged↗
PubMed1988

Transrectal US of the seminal vesicles and ejaculatory ducts: clinical correlation.

Transrectal ultrasonography (US) provides excellent anatomic detail of pathologic changes in the seminal vesicles and ejaculatory ducts. Fifty-two patients with US findings of seminal vesicle dilatation or cysts, ejaculatory duct cysts, or seminal vesicle or ejaculatory duct calculi were given questionnaires concerning a broad spectrum of genito-urinary symptoms. Compared with age-matched controls with normal US findings, patients with calculi in the seminal vesicles or ejaculatory ducts had a significantly increased prevalence of hematospermia and ejaculatory pain (P less than .01), and patients with cystic dilatation of the seminal vesicles were more likely to have perineal pain. Large midline cysts containing calculi or debris were symptomatic and probably represent müllerian duct remnants. Small cysts of the ejaculatory ducts were asymptomatic. Transrectal US may provide clinical insight into the causes of significant genitourinary symptoms that may previously have been ascribed to chronic nonbacterial prostatitis or have been considered to be idiopathic.

Calculi↗
PubMed1988

Early prostate cancer: diagnostic costs of screening transrectal US and digital rectal examination.

A screening study with transrectal ultrasound (US) and digital rectal examination to diagnose early prostate cancer was performed to calculate diagnostic costs. The total costs of screening 784 men were $130,400 with transrectal US and $41,080 with digital rectal examination. Per diagnosed cancer, the costs were $6,520 for transrectal US and $4,108 for digital rectal examination, a difference of 37%. The costs per early diagnosed cancer (stage A or B) were $7,671 and $5,869 for transrectal US and digital rectal examination, respectively--a difference of 23%. The costs per early cancer that would have been advanced if diagnosed without screening were $22,177 for transrectal US and $28,528 for digital rectal examination--a difference of 22% in favor of transrectal US. Equations for these relative costs were generated for transrectal US and digital rectal examination. Costs are related to changes in prevalences and to changes in the stages of prostate cancer when diagnosed without screening.

Cost-Benefit Analysis↗
PubMed1988

Interleukin 1 binds to specific receptors on human keratinocytes and induces granulocyte macrophage colony-stimulating factor mRNA and protein. A potential autocrine role for interleukin 1 in epidermis.

Cultured human keratinocytes have been shown to produce IL-1 alpha and beta mRNA and protein. IL-1 biological activity has been identified in normal human epidermis; in vitro, most biologically active IL-1 resides in a cell-associated compartment. The potential for autocrine effects of IL-1 on human keratinocytes was assessed by measurement of keratinocyte IL-1 receptors. Both high- and low-affinity cell surface receptors that bound recombinant (r) IL-1 alpha and beta with comparable affinities could be identified on cultured human keratinocytes, using 125I-labeled rIL-1. Chemical crosslinking experiments identified a cell surface molecule of roughly 72,500 Mr that bound 125I-labeled IL-1, similar to the molecular weight of previously described IL-1 receptors on fibroblasts, B cells, and T cells. To assess the biological consequences of keratinocyte IL-1 binding, granulocyte-macrophage colony-stimulating factor (GM-CSF) gene expression was measured. The addition of exogenous rIL-1 alpha led to a dose-dependent increase in the accumulation of GM-CSF mRNA, as measured by a sensitive and specific S1 nuclease assay. This increase in mRNA was reflected in a marked increase in GM-CSF biological activity as measured by proliferation of blast cells from chronic myelogenous leukemia patients. The biological activity was completely inhibitable by an antibody to human rGM-CSF. GM-CSF activates mature neutrophils and macrophages and appears to enhance the efficiency of Langerhans cell antigen presentation to T cells. Release of IL-1 from injured or activated keratinocytes may lead to enhanced epidermal GM-CSF gene expression via an autocrine mechanism, thus enhancing local host defense.

Cells, Cultured↗
PubMed1988

Introduction of interleukin-3 gene into stromal cells from the bone marrow alters hemopoietic differentiation but does not modify stem cell renewal.

Cloned endothelial-adipocytes from the stroma of mouse bone marrow (designated 14F1.1) induced growth of stem cells in vitro, accompanied by either pre-B lymphopoiesis or myelopoiesis. We examined the contribution of colony stimulating factors (CSF) to the process. mRNA for GM-CSF, interleukin 3 (IL3), G-CSF, and IL4 could not be detected in the stromal cells. Expression of IL3 gene, achieved by transfection of 14F1.1 cells with a plasmid carrying an IL3 cDNA, shifted the direction of differentiation but did not improve stem cell maintenance. It is proposed that novel stromal cell factors, distinct from known CSFs, regulate stem cell renewal.

Adipose Tissue↗
PubMed1988

The molecular cloning of interleukins 4, 5 and 6: multifunctional hemopoietic growth factors.

We summarize here our recent studies on the cloning and characterization of three lymphokines which are produced by activated T cells. Interleukins 4, 5 and 6 are involved in the regulation of B cell activation, proliferation and differentiation. IL-4 can activate resting B cells, while IL-5 stimulates the proliferation of activated B cells. Both of these factors also have a role in regulating the isotype of immunoglobulin produced by cultures of D cells. IL-6 appears to induce the differentiation of B cells to secrete high levels of immunoglobulin. In addition, each of these factors is involved in the regulation of other lineages of hemopoietic cells. Thus, T cells control multiple lineages of myeloid and lymphoid cells through the diverse actions of multiple lymphokines. IL-6 is exceptional because it is produced by a variety of cell types, and its action is not restricted to hemopoietic cells.

B-Lymphocytes↗
PubMed1987

B cell growth-promoting activity of recombinant human interleukin 4.

Human interleukin 4 (IL-4), also known as B cell stimulatory factor 1, is a T cell-derived glycoprotein consisting of 129 amino acids for which a cDNA has been recently isolated. IL-4 displays little or no B cell growth factor (BCGF) activity in the standard anti-IgM costimulatory assay using suboptimal concentrations of soluble anti-IgM antibody whereas the low m.w. BCGF is very active. When insolubilized anti-IgM was used as the costimulating agent, both IL-4 and the low m.w. BCGF were found to promote B cell proliferation. Human IL-4 is able to induce the proliferation of B lymphocytes preactivated for either 1 day with insolubilized anti-IgM antibody or for 3 days with Staphylococcus aureus strain Cowan I. However, IL-4 is poorly mitogenic for B cells preactivated for 1 day with the Staphylococcus strain whereas the low m.w. BCGF strongly enhances the proliferation of these B cells. These two findings demonstrate that the preactivation signal necessary to induce human B cells to proliferate in response to IL-4 is critical. The increased tritiated thymidine ([3H]dThd) uptake in preactivated B cell cultures with IL-4 reflects cel proliferation because cell cycle analysis demonstrates that IL-4 induces activated B cells to enter the S and G2/M phases of the cell cycle and the addition of IL-4 to preactivated B cell cultures permits the recovery of three- to fourfold more B cells after 4 days of culture. IL-4 and the low m.w. BCGF act in concert to induce the proliferation of anti-IgM-preactivated B cells as demonstrated by [3H]dThd uptake and cell cycle analysis. In striking contrast to the demonstrated antagonistic effect of interferon-gamma on the IL-4-induced expression of the low affinity receptor for IgE (Fc epsilon RL/CD23), on B cells, it was found that interferon-gamma enhanced the IL-4-induced proliferation of anti-IgM-preactivated B cells. Finally, it was found that IL-4 had to be present continuously during the culture period to exert an optimal growth-promoting effect on B cell blasts. As a conclusion, IL-4 is able to induce the proliferation of an appropriately activated subpopulation of human B cells.

B-Lymphocytes↗
PubMed1987

Recombinant interleukin 4 promotes the growth of human T cells.

Recently, we reported the isolation of a cDNA clone that encodes a polypeptide which has B cell and T cell growth factor activities. The amino acid sequence of this polypeptide deduced from the nucleotide sequence of the cDNA clone showed significant homology with mouse B cell stimulating factor-1. Because of its multiple biologic activities, it was designated interleukin 4 (IL-4). Here we describe the effects of supernatants of Cos-7 mouse cells transfected with the IL-4 coding cDNA clone in a mammalian expression vector, on human thymocyte T cells and T cell clones. The T cell growth-promoting effect of IL-4 on preactivated T cells was not inhibited by monoclonal antibodies against IL-2 or the IL-2 receptor, indicating that the IL-4 activity is independent from IL-2 or the IL-2 receptor. IL-4 induces a low proliferative response in thymocytes and peripheral blood lymphocytes, but the response was considerably enhanced by preactivation of the thymocytes or peripheral blood T cells. Both T4+ and T8+ antigen-specific proliferative and cytotoxic T cell clones and T3 natural killer clones proliferated in response to IL-4. But one of six T4+ and one of four T8+ T cell clones were consistently found to be unresponsive. The proliferative responses to IL-4 were always lower than those obtained with IL-2. Most of the T cell clones generally became unresponsive to IL-4 10 days after stimulation, but still responded well to IL-2. These results indicate that the responsiveness to IL-4 is relatively short lasting and is regulated by activation signals. Interestingly, IL-4 acted in synergy with IL-2 in promoting the growth of T cell clones. Our results establish that IL-4 can act as a T cell growth factor independently of IL-2.

Animals↗
PubMed1987

Autocrine growth of T cells independent of interleukin 2: identification of interleukin 4 (IL 4, BSF-1) as an autocrine growth factor for a cloned antigen-specific helper T cell.

Interleukin 4 (IL 4), formerly known as B cell stimulatory factor 1 (BSF-1), has recently been described as a growth factor for T cells. The role of IL 4 in the putatively IL 2-independent growth of certain cloned T helper cells is unclear. D10.G4.1 (D10) is a conalbumin-specific helper T cell that has been employed extensively in the analysis of T cell activation and as an assay for the detection of IL 1. Previously, it was thought that IL 1 induced the expression of IL 2 receptors on D10 cells, thereby permitting D10 to proliferate in response to endogenously produced IL 2. However, we cannot detect IL 2 mRNA or protein in D10 cells or their supernatants as determined by the following criteria: monoclonal antibodies that neutralize the in vitro activity of murine IL 2 do not block the IL 1-dependent proliferation of D10 cells; no competitive binding for high-affinity IL 2 receptors with 125I-labeled IL 2 can be detected with medium conditioned by activated D10 cells; and Northern blot analysis and S1 nuclease protection assays, performed with cDNA probes for IL 2, do not detect mRNA for IL 2 under a variety of different activation conditions that foster autocrine growth of D10 cells. In contrast, activated D10 cells produce both IL 4 mRNA and protein as judged by similar criteria. Purified IL 4 has significant TCGF activity as measured by proliferation of HT-2 cells. This activity can be blocked completely by a monoclonal antibody to IL 4 (11B11). The proliferation of D10 cells in the presence of 3D3 (a clonotype-specific monoclonal anti-T cell receptor antibody) and IL 1 can be blocked completely by 11B11 antibody. Highly purified IL 4 alone cannot induce the proliferation of resting D10 cells; however, equivalent amounts of IL 4 in the presence of recombinant IL 1 induce significant D10 proliferation. Therefore, IL 1 appears to render D10 cells responsive to their autocrine growth signal. These data indicate that IL 4 serves as the autocrine T cell growth factor for D10 cells, and that exogenous IL 1 is required for the transduction of this growth signal. This may represent a more broadly applicable mechanism for the growth of certain subsets of T helper cells.

Animals↗
PubMed1987

Human recombinant interleukin 4 induces Fc epsilon receptors (CD23) on normal human B lymphocytes.

Human rIL-4 is able to induce the expression of low-affinity receptors for IgE (Fc epsilon RL/CD23) on resting B lymphocytes, as determined by the binding of either the anti Fc epsilon RL/CD23-specific mAb 25 or IgE. Stimulation of B cells with insolubilized anti-IgM antibody increases the number of cells expressing Fc epsilon RL/CD23 upon culturing with IL-4 and enhances the level of Fc epsilon RL/CD23 expression on these cells. Fc epsilon RL/CD23 induction is specific for IL-4 since IL-1 alpha, IL-2, IFN-gamma, B cell-derived B cell growth factor (BCGF), and a low-molecular-weight BCGF were ineffective. IFN-gamma strongly inhibited the induction of Fc epsilon RL/CD23 by IL-4.

B-Lymphocytes↗
PubMed1987

A single bone marrow-derived stromal cell type supports the in vitro growth of early lymphoid and myeloid cells.

A clonal cell line (ALC) derived from murine bone marrow stroma is capable of supporting the continuous, in vitro growth of early lymphoid and myeloid cell populations. The growth-promoting effects of ALC are in part mediated through M-CSF and a pre-B cell growth factor, both of which accumulate in ALC-culture supernatant. To analyze the lymphoid growth factor produced by ALC cells, we derived a pre-B cell indicator line that is dependent on ALC-growth-conditioned medium. Using a combination of biological and biochemical analyses, we have established that the pre-B cell growth factor produced by ALC cells is distinct from IL-1, IL-2, IL-3, and IL-4 (BSF-1), suggesting that the early stages of B-cell development are regulated by a unique stroma-derived growth factor.

Animals↗
PubMed1987

Structural analysis of the mouse chromosomal gene encoding interleukin 4 which expresses B cell, T cell and mast cell stimulating activities.

Based on homology with the mouse interleukin 4 (IL-4) cDNA that expresses B cell, T cell, and mast cell stimulating activities (Lee, F. et al., (1986) Proc. Natl. Acad. Sci. USA 83, 2061), we have isolated from a Balb/c mouse liver DNA library the mouse chromosomal gene and analyzed its overall structure. The gene occurs as a single copy in the haploid genome and contains four exons and three introns. The exon sequences almost completely match the cloned cDNA sequence. Interestingly, there is a fairly high degree of homology between mouse IL-4 and mouse IL-2 genes extending more than 200 bp upstream of a "TATA" like sequence located 20 bp upstream of the transcription initiation site. These sequences may play an important role in the regulated expression of this gene in concanavalin A or antigen-stimulated T lymphocytes. The supernatant of COS7 cells transfected with plasmid DNA containing the entire gene exhibited both T cell growth factor and mast cell growth factor activities.

Amino Acid Sequence↗