Search PubMed⌕ Search

Biomedical subjects

E Alesse

Publications and source records attributed to E Alesse.

At least 37 records · Page 2Linked to original sources

Cellular dysmetabolism: the dark side of HIV-1 infection.

The progression to disease in subjects infected with the human immunodeficiency virus type I (HIV-1) cannot be explained solely on the basis of the infecting HIV-1 species. There is recent evidence that abnormalities in the cellular metabolism are crucial to the progression of the infection through common pathways that involve the induction of apoptosis and oxidant stress. Conversely, the low propensity of lymphocytes to undergo apoptosis, a normal redox status, and a balanced ceramide metabolism appear to predict a slow progression, or the non-progression at all, of the infection. It is likely that the ability of the host to maintain over time a balanced cellular metabolism despite the chronic infection with the virus contributes to the especially favourable outcome of an otherwise fatal infection seen in a discrete subgroup of HIV-1-infected individuals (long-term non-progressors) who might never experience any of the adverse effects of HIV-1 infection and will never demonstrate disease progression. Furthermore, this background supports the hypothesis that adjunctive therapies directed at correcting certain abnormalities of cellular metabolism seen in the infected host should be given in combination with antiretroviral drugs in order to slow the progression of the infection.

Acquired Immunodeficiency Syndrome↗

Heavy-metal modulation of the human intercellular adhesion molecule (ICAM-1) gene expression.

The intercellular adhesion molecule 1 (ICAM-1) can be induced on many different cell types by a set of various modulators (IL1 beta, TNF, LPS, IFN-gamma), which are released during the inflammatory process. We have investigated the possibility that other factors, related to the stress and biophysical perturbations of the inflammatory response, may also modulate ICAM-1. Here, we report that heavy metals, in particular zinc, can enhance the expression of the ICAM-1 gene on cells actively involved at different levels during inflammation. Kinetic studies of ICAM-1 gene expression shows a maximum level of induction 4 h after treatment with metals, followed by a rapid decrease to basal levels within 12 h. The effect on enhanced gene expression is mostly due to a rapid increase of the transcriptional rate as shown by nuclear run-on experiments. In B lymphoblastoid cells, but not in fibroblasts, the increase in RNA expression seems significantly greater that the subsequent increase in protein expression, suggesting that a further point of post-transcriptional regulation of ICAM-1 occurs and may be linked to the cellular specificity. may be linked to the cellular specificity.

Cadmium↗

Human immunodeficiency virus type-1 tat enhances interleukin-2 promoter activity through synergism with phorbol ester and calcium-mediated activation of the NF-AT cis-regulatory motif.

Interference with T cell activation signals by Human immunodeficiency virus (HIV) gene products is suggested to contribute to the impairment of immune functions observed in AIDS. Interleukin-2 (IL-2) and HIV share common stimulatory signals triggered during T cell activation. The role of HIV tat, which is the main enhancing factor for viral LTR, in the regulation of IL-2 gene transcription has been studied following transient expression of the tat gene in phorbol ester and calcium ionophore-activated Jurkat cells transfected with IL-2 promoter-chloramphenicol acetyltransferase reporter constructs. We observed that tat increased the IL-2 promoter transcriptional activity in response to phorbol ester and ionomycin. This tat-dependent synergism mapped to the (-279 to -263 bp) NFAT motif of the IL-2 enhancer, which was sufficient to be transactivated by tat. Our data suggest that tat links T cell activating signals to the shared IL-2 and HIV regulation. This may play a role in the early phase of HIV infection.

Calcium↗

Effects of cadmium on lymphocyte activation.

The effects of cadmium (Cd) on phytohemoagglutinin or phorbol myristate acetate-induced lymphocyte activation were investigated and a dose-dependent inhibition of cell proliferation was found. Kinetic studies revealed that the Cd-sensitive step is an early event of T cell stimulation. Failure of IL2 secretion and reduction of IL2 receptor expression in the Cd-treated cells are also reported. Regardless of which mechanism is responsible for Cd effects, our studies show that the inhibition of lymphocyte activation is associated with reduced [3H]phorbol dibutyrate binding to Ca2+-phospholipid-dependent protein kinase and altered breakdown of phosphatidylinositols. Thus, Cd interferes with two biochemical events which play a critical role in lymphocyte signal transduction and activation.

Adult↗

Polyclonal B lymphocyte activation in progressive systemic sclerosis.

In 13 women affected by progressive systemic sclerosis (PSS) the activation state of circulating B lymphocytes by use of monoclonal antibodies and the in vitro IgG, IgA, IgM synthesis by peripheral blood mononuclear cells (PBMC) cultured with or without pokeweed-mitogen (PWM) were evaluated. The total and "activated" B lymphocytes were increased. The supernatants of PBMC cultured without PWM contained increased IgG and IgA levels; only in two patients, however, were IgM levels increased. The addition of PWM augmented IgG and IgA levels only in three cases and never IgM levels. Our results indicate that the polyclonal hyperactivity of B lymphocytes is a major immunologic feature in PSS patients. The lack of increase of in vitro immunoglobulin synthesis in the presence of PWM suggests either that B lymphocytes, already maximally activated in vivo, are unresponsive to further mitogen stimulation or that a more complex imbalance of B lymphocyte responsiveness to PWM may exist.

Adult↗

Effect of hrTNF alpha on TxB2 release by macrophages.

Peritoneal rat macrophages incubated with human recombinant tumour necrosis factor (hrTNF alpha) released 2-3 times more thromboxane (TxB2) than untreated macrophage controls, a result similar to that obtained by incubating them with endotoxin (ET) or calcium ionophore A23187.

Animals↗

Mitogen dose-dependent effect of weak pulsed electromagnetic field on lymphocyte blastogenesis.

The effects of pulsed extremely low frequency electromagnetic fields on human peripheral blood lymphocyte mitogenesis induced by phytohaemoagglutinin, concanavalin A or calcium ionophore A23187 were studied. The dependence of the field effect on mitogen concentrations was investigated. Field exposure produced strong inhibition of DNA synthesis when optimal doses of mitogens were used, confirming our previous findings. Opposite effects were observed at suboptimal concentration of mitogens. Experiments performed by exposing cell cultures to the field for short periods indicated that a field application of at least 6 h is needed to influence irreversibly lymphocyte blastogenesis.

Calcimycin↗

Augmentation of thromboxane production in vitro by polymorphonuclears and macrophages exposed to IL1/LP.

Human peripheral blood polymorphonuclear leukocytes (PMNs) and murine peritoneal macrophages (M phi) were stimulated to generate thromboxane upon treatment with highly purified human interleukin 1/leukocytic pyrogen (IL1/LP) at various concentrations. Thromboxane B2 was measured by radioimmunoassay in the cell-free supernatants of cell suspensions after 1 hour incubation at 37 degrees C. Thromboxane B2 amounts increased in a way which depended on the dose of IL1 added to the cell cultures.

Animals↗

In vitro enhanced thromboxane B2 release by polymorphonuclear leukocytes and macrophages after treatment with human recombinant interleukin 1.

Macrophages (M phi) and polymorphonuclear leukocytes (PMNs) are cell types that interact with bacterial endotoxin and play key roles in mediating the inflammatory reaction. We examined the ability of rat peritoneal macrophages and human PMNs to synthesize thromboxane A2 (detected as TxB2) in response to human recombinant interleukin 1 (hrIL1). TxB2 levels were measured by radioimmunoassay in the cell-free supernatant of cell suspensions after 1 hr incubation at 37 degrees C. TxB2 release by both PMNs and M phis was increased in a dose-dependent manner by hrIL1.

Animals↗

Comparative effects of indomethacin and proglumetacin on 6-oxo-PGF1 alpha released ex vivo by rat gastric mucosa.

The authors compare the effect of indomethacin and proglumetacin on the production of prostacyclin in the rat gastric mucosa, and investigate the potential ulcerogenic effect elicited by the two drugs. The results show that indomethacin and proglumetacin, at doses giving similar inhibition of gastric-protacyclin synthesis, drastically differ in their gastric ulcerogenic effects.

6-Ketoprostaglandin F1 alpha↗

Effect of supernatants from PHA-stimulated and non-stimulated lymphocyte cultures on thromboxane B2 release by polymorphonuclear leukocytes in vitro.

The present study involves the determination of the effect of supernatants obtained from mitogen-induced lymphocytes of human tonsils and containing lymphotoxins on human peripheral blood polymorphonuclear leukocytes (PMNs). PMNs treated with supernatants from phytohemagglutinin-stimulated lymphocytes were found to increase the release of thromboxane B2, compared to normal control levels. This increase was blocked by the preincubation of PMNs with indomethacin. The production or increase in production of thromboxanes may be induced by lymphotoxins since these substances have been reported to activate phospholipase A2 in target cell membranes, which may result in release of the thromboxane precursor, arachidonic acid.

Humans↗

Enhanced thromboxane synthesis and vacuolization in human polymorphonuclear leucocytes induced by human lymphokine containing supernatants.

PMN's were cultivated in vitro and treated with supernatants obtained from mitogenic-induced lymphocytes of human tonsil. Cytoplasmic vacuolization increased with time and there was a lower number of neutrophilic clumps in the culture treated with a supernatant containing lymphotoxin. In addition, the PMN's released more thromboxane B2 which was inhibited by indomethacin. We conclude that the action of lymphotoxin on the target PMN's is not mediated by the production of thromboxane B2.

Adult↗