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Biomedical subjects

E J Fox

Publications and source records attributed to E J Fox.

At least 19 recordsLinked to original sources
PubMed1996

Extraosseous primary and recurrent giant cell tumors: transforming growth factor-beta1 and -beta2 expression may explain metaplastic bone formation.

Giant cell tumor (GCT) of bone is a locally aggressive neoplasm with a high incidence of recurrence, usually at the site of previous osseous involvement. Primary and recurrent intraosseous lesions typically are lytic and do not show evidence of tumor-associated osteogenesis. Rarely, GCT recurs or is primary within soft tissue, and not infrequently, these extraosseous lesions show metaplastic bone formation that is visible radiographically. The authors report two recurrent and one primary case of extraosseous GCT, all of which exhibited significant deposits of metaplastic bone localized to the periphery of the lesions. In situ hybridization showed messenger RNA (mRNA) for transforming growth factor beta1 (TGF-beta1) and transforming growth factor beta2 (TGF-beta2) in neoplastic stromal cells and osteoclast-like giant cells within the recurrent and primary extraosseous tumors as well as in active osteoblasts on the surfaces of recently formed spicules of metaplastic bone. In situ hybridization also revealed mRNA for TGF-beta1 and TGF-beta2 in primary intraosseous tumors from these cases and from four cases in which neither extraosseous recurrence nor osseous metaplasia was identified. In the microenvironment of the extraosseous soft tissue, production of these osteoinductive growth factors by GCT may have a paracrine effect on mesenchymal progenitor cells, thereby stimulating the osteoblastic differentiation and metaplastic bone formation associated with these lesions.

Adult↗
PubMed1988

The Tullio phenomenon and perilymph fistula.

Establishing the diagnosis of perilymph fistula remains a dilemma. At this time, identification of an active perilymph fistula can be confirmed only by surgery. On the basis of clinical history and audiovestibular testing, 54 patients underwent middle ear exploration for possible perilymph fistula at the Colorado Ear Clinic between July 1980 and June 1986. This group represents approximately 1% of all surgical procedures performed during that period. Seven patients (12%) were found to have the Tullio phenomenon preoperatively. Six of these were found to have active, free-flowing fistulas at the time of exploration. The presence of a Tullio phenomenon may be helpful in preoperative assessment of a patient with suspected perilymph fistula.

Acoustic Stimulation↗
PubMed1987

T suppressor cell growth factor and anti-CD3 antibodies stimulate reciprocal subsets of T lymphocytes.

Because of the central role of IL-2 in clonal expansion of T cells, we have postulated that lymphocyte subpopulations with opposing regulatory functions might be independently regulated by differential requirements for expression of cell-surface IL-2-R. Purified CD4+ and CD8+ cells proliferated in an IL-2-dependent manner to crosslinked anti-T cell receptor antibodies (anti-CD3-Seph). Similarly, both CD4+ and CD8+ cells became IL-2 responsive after incubation in T suppressor cell growth factor (TsGF), a newly described approximately 8,000 Mr product of activated CD4+ cells. In support of our hypothesis, however, we observed that subpopulations of CD4+ and CD8+ cells, possessing distinct cell-surface antigens, showed differential responses to these stimuli. Those cells of suppressor-inducer or suppressor-effector phenotype failed to proliferate when cultured in anti-CD3-Seph plus IL-2, but did proliferate in an IL-2-dependent manner to TsGF. Furthermore, the suppressor-effector population was unresponsive to TsGF plus IL-2 when cocultured in anti-CD3-Seph, suggesting that functionally induced Ts may be refractory to growth stimuli. Conversely, cells with helper-inducer or cytolytic phenotype proliferated when incubated in anti-CD3-Seph and IL-2, while remaining essentially unresponsive to TsGF and IL-2. The results could not be explained by differences in the level of CD3 expression by the T cell subsets. Thus, cells within the helper and suppressor lineages appear to have distinct and reciprocal patterns for the induction of IL-2 responsiveness.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Sequential effects of prostaglandins and interferon-gamma on differentiation of CD8+ suppressor cells.

We have previously demonstrated that differentiation of CD8+ Tp44- suppressor cells in pokeweed mitogen (PWM)-stimulated cultures requires soluble factors elaborated by CD4+ cells and monocytes, and that the monocyte signal for such differentiation can be replaced by prostaglandin E2 (PGE2). In this study, we explored the ability of interleukin 2 (IL 2) and interferon-gamma (IFN-gamma) to replace the CD4+ signal. When IL 2 or IFN-gamma was used at concentrations equivalent to those present in supernatants of PWM-pulsed cultures of CD4+ cells, no effect on differentiation of CD8+ cells was observed. However, a potent suppressor inducing activity was detected when IFN-gamma, but not IL 2, was mixed with supernatants derived from cultures of PWM-pulsed purified monocytes (M phi sup) or with 10(-8) M PGE2. Differentiated CD8+ suppressor cells (Ts) inhibited both PWM-stimulated proliferative response of CD4+ cells and immunoglobulin production by B cells. The signals mediated by the M phi sup or PGE2 and IFN-gamma were shown to act sequentially. That is, M phi sup or PGE2 was required initially, followed by an IFN-gamma-dependent differentiative step. These studies thus suggest a cascade of cellular interactions involving monocytes, CD4+ cells, and CD8+ Ts precursors that are required for the differentiation of CD8+ suppressor effector cells.

Antibody Formation↗
PubMed1986

Opposing immunoregulatory functions of CD8+ lymphocytes: a requirement for monocytes in suppressor cell induction.

We have found that the induction of suppressor T cell (Ts) function in pokeweed mitogen (PWM)-stimulated cultures of peripheral blood mononuclear cels (PBMC) depends on the concentration of monocytes in inductive cultures. When cultured for 7 to 8 days in a physiologic concentration of monocytes (10 to 15%) suppressor cells differentiated with the surface phenotype CD8+ DR+ Leu-7- Leu-8+ Tp44-. Suppressor function, as assessed in secondary cultures of fresh PWM-stimulated CD4+ cells, was partially radiosensitive, and its induction could be partially inhibited by treatment with indomethacin. Culture supernatants of PWM-pulsed CD4+ cells could induce CD8+ suppressor cells only when monocytes were included in cultures for supernatant production. In marked contrast, if the monocyte concentration of PWM-stimulated T cells was reduced to less than 5%, CD8+ cells harvested from such cultures substantially augmented proliferation of PWM-stimulated CD4+ cells in assay cultures. Amplifier cells from monocyte-depleted cultures, were also DR+Tp44-. Suppressive activity of the CD8+ subset was restored simply by addition of monocytes to purified T cells, reconstituting the concentration present among unfractionated PBMC. Addition of IL 1 could not replace the requirement of monocytes for suppressor cell induction either in PWM-stimulated primary cultures or in culture supernatants. The data thus demonstrate that the regulatory activity of CD8+ lymphocytes is critically dependent on the conditions of cellular activation; at concentrations of monocytes normally present in peripheral blood, PWM stimulation induced potent suppressor activity, whereas under conditions of moderate monocyte depletion the regulatory activity of the same phenotypic subset of CD8+ cells was reversed. The experiments thus suggest that the functional consequences of an activating stimulus may depend on regulatory effects of monocytes in CD8+ suppressor cell induction.

Antigens, Surface↗
PubMed1986

Human suppressor T cells: induction, differentiation, and regulatory functions.

T-cell-mediated suppression of human immune responses involves a complex interaction between distinct lymphocyte subsets with suppressor-inducer and suppressor-effector functions. Recent studies with subset-specific monoclonal antibodies have defined a characteristic phenotype of suppressor-inducer cells (CD4+ Leu8+ 2H4+ 4B4-) that can be distinguished from that of helper cells for antibody synthesis (CD4+ Leu8- 2H4- 4B4+). Similarly, suppressor-effector cells (CD8+CD11+Tp44-) can typically be defined as a subset separable from cytotoxic T cells (CD8+CD11-Tp44+). Both antigen-specific and nonspecific interactions are important in suppressor T-cell activation and function. Soluble signals required for differentiation of CD8+ suppressor cells include an indomethacin-sensitive monocyte product and interferon gamma. In contrast, proliferation of the CD8+ suppressor cell subset depends on stimulation first by a product of CD4+Leu8+ cells, T suppressor cell growth factor, and second by interleukin 2. Although the molecular basis of antigen-specific interactions between CD4+ and CD8+ cells in suppressor cell generation has not been defined, it may involve both conventional, presumably MHC-restricted, interactions between antigen and antigen receptors, as well as anti-idiotypic interactions of suppressor-effectors with determinants on suppressor-inducer receptors. Progress in elucidating requirements for activation, growth, and differentiation of suppressor cells should facilitate long-term culture of such cells and lead to clearer understanding of mechanisms of suppressor-cell mediated immunoregulation.

Antibodies, Monoclonal↗
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

The relationship between the human sperm hypoosmotic swelling test, routine semen analysis, and the human sperm zona-free hamster ovum penetration assay.

The functional integrity of sperm membranes of 270 semen samples collected from fertile men and the male partners in couples with infertile marriages was assessed by the hypoosmotic swelling test and the results correlated with routine semen analysis and the human sperm zona-free hamster ovum penetration assay. Semen samples with abnormal semen parameters had lower values of percentage of swollen sperm after hypoosmotic treatment in comparison with those with normal semen parameters. A weak positive correlation was observed between sperm swelling and sperm morphologic features (r = 0.32, P less than 0.05) and between sperm swelling and sperm motility (r = 0.22, P less than 0.05). Insignificant correlation was observed between sperm swelling and in vitro sperm fertilizing capacity, as assessed by the zona-free hamster ovum penetration assay. The results indicate that the sperm swelling test and the zona-free hamster ovum penetration assay are evaluating different functional qualities of sperm that are apparently not associated with each other.

Animals↗
PubMed1984

Cellular requirements for induction of human primary proliferative responses to trinitrophenyl-modified cells.

Cellular requirements for induction of primary proliferative responses by human T cells to trinitrophenylated autologous stimulators have been characterized. Substantial proliferative responses were observed with each of the Ia+ stimulator populations tested. Nevertheless, major differences in the hapten specificity of such responses were observed. Thus purified macrophages/monocytes (M phi) when TNP-modified induced responses that were relatively modest in absolute magnitude, but were highly hapten specific. This reflected the very limited capacity of purified M phi to induce proliferation when unmodified, i.e., an autologous mixed leukocyte response (AMLR). In contrast, unmodified M phi-depleted B plus null cells were potent stimulators of AMLR, but hapten modification did not significantly enhance the responses induced by these cells. Moreover, when M phi were added to B plus null cell stimulators AMLR responses were reduced and, with TNP-modified stimulators, hapten-specific responses were restored. The data thus suggest that M phi may have important roles in induction of primary T cell responses to conventional antigens but function largely as regulators rather than stimulators of AMLR. Finally, we have introduced a novel antigen-presenting cell population, the irradiated Ia+ TNP-specific cloned T cell. The possibility that such cells may utilize autostimulatory positive feedback circuits for activation of naive T cells and in interactions between subpopulations of hapten-reactive T cells is discussed.

Clone Cells↗
PubMed1978

Failure of withdrawal bleeding during combined oral contraceptive therapy: "amenorrhoea on the pill".

Serum follicle stimulating hormone, luteinising hormone and oestradiol-17beta concentrations have been measured in 21 patients with failure of withdrawal bleeding during combined oral contraceptive therapy and 21 matched controls with a normal bleeding pattern. Gonadotrophin and oestradiol-17beta concentrations were effectively suppressed in all patients during the phase of contraceptive ingestion. During the week between courses of treatment, there was a significant rise in the gonadotrophin (p less than 0.02) and oestradiol (p less than 0.05) concentrations in the patients but not in the controls. It is suggested that patients with failure of withdrawal bleeding during combined oral contraceptive therapy may have higher total oestrogen levels during the treatment-free week because of a less persistent suppression of hypothalamic-pituitary-ovarian function.

Amenorrhea↗