Ammonium Trichloro Research Articles

Influence of the Immunomodulator Ammonium Trichloro (dioxoethylene-0,0’) Tellurate (AS101) on Human Sperm Apoptotic Markers in Vitro

The objective of this research was to evaluate the influence of the immunomodulator ammonium trichloro (dioxoethylene-0,0’) tellurate (AS101) on caspase activity, mitochondrial transmembrane potential (δ Ψm), and DNA stability in human sperm.

Inhibition of Interleukin-10 by the Immunomodulator AS101 Reduces Mesangial Cell Proliferation in Experimental Mesangioproliferative Glomerulonephritis: ASSOCIATION WITH DEPHOSPHORYLATION OF STAT3

Mesangial cell (MC) proliferation is essential for the pathogenesis and progression of glomerular disease. Using an acute model of mesangial proliferative glomerulonephritis (Thy1 GN), we show that neutralization of interleukin (IL)-10 greatly ameliorated the disease as expressed by both decreased MC expansion and proteinuria. Treatment with the tellurium compound AS101 (ammonium trichloro(dioxoethylene-o,o')tellurate) resulted in favorable effects provided that the compound was administered 24 h before insult, whereas partial effects were obtained when administered after insult. We identified STAT3 as playing a pivotal role in IL-10-induced MC proliferation in vitro and in vivo. IL-10 activates MC STAT3 in vitro as expressed by its phosphorylation and nuclear translocation. The role of STAT3 in MC proliferation induced by IL-10 was deduced from results showing that IL-10-induced proliferation was abrogated if MC transfected with STAT3 antisense oligonucleotides were used or if cells were incubated with inhibitors of STAT3. AS101 deactivates STAT3 in control but not in MC transfected with IL-10 antisense oligonucleotides. Inactivation of STAT3 prevents reduction of MC proliferation by AS101. We further demonstrate the role of STAT3 in the regulation of cell cycle and survival regulatory proteins by AS101 in MC via inhibition of IL-10. IL-10 increased MC expression of Bcl-2 and Bcl-X1 and simultaneously decreased the levels of p27kip1. These survival factors were decreased by AS101 in a STAT3- and IL-10-dependent manner, whereas p27kip1 was similarly increased. In Thy1 GN, phosphorylated STAT3 in glomerular MC peaked at day 6 and correlated with MC expansion. Neutralization of IL-10 or its inhibition by AS101 abolished phosphorylation of STAT3. This effect positively correlated with amelioration of the disease. These in vitro and in vivo studies indicate that the autocrine MC growth factor IL-10 induces MC proliferation via STAT3. We suggest that IL-10 or its downstream target STAT3 might be therapeutic targets for kidney diseases induced by mesangial proliferation.

Ammonium trichloro(dioxoethylene-o,o')tellurate (AS101) sensitizes tumors to chemotherapy by inhibiting the tumor interleukin 10 autocrine loop.

Cancer cells of different solid and hematopoietic tumors express growth factors in respective stages of tumor progression, which by autocrine and paracrine effects enable them to grow autonomously. Here we show that the murine B16 melanoma cell line and two human primary cultures of stomach adenocarcinoma and glioblastoma multiforme (GBM) constitutively secrete interleukin (IL)-10 in an autocrine/paracrine manner. This cytokine is essential for tumor cell proliferation because its neutralization decreases clonogenicity of malignant cells, whereas addition of recombinant IL-10 increases cell proliferation. The immunomodulator ammonium trichloro(dioxoethylene-o,o')tellurate (AS101) decreased cell proliferation by inhibiting IL-10. This activity was abrogated by exogenous addition of recombinant IL-10. IL-10 inhibition by AS101 results in dephosphorylation of Stat3, followed by reduced expression of Bcl-2. Moreover, these activities of AS101 are associated with sensitization of tumor cells to chemotherapeutic drugs, resulting in their increased apoptosis. More importantly, AS101 sensitizes the human aggressive GBM tumor to paclitaxel both in vitro and in vivo by virtue of IL-10 inhibition. AS101 sensitizes GBM cells to paclitaxel at concentrations that do not affect tumor cells. This sensitization can also be obtained by transfection of GBM cells with IL-10 antisense oligonucleotides. Sensitization of GBM tumors to paclitaxel (Taxol) in vivo was obtained by either AS101 or by implantation of antisense IL-10-transfected cells. The results indicate that the IL-10 autocrine/paracrine loop plays an important role in the resistance of certain tumors to chemotherapeutic drugs. Therefore, anti-IL-10 treatment modalities with compounds such as AS101, combined with chemotherapy, may be effective in the treatment of certain malignancies.

Hair growth induction by the tellurium immunomodulator AS101: association with delayed terminal differentiation of follicular keratinocytes and ras‐dependent up‐regulation of KGF expression

The synthetic immunomodulator AS101[ammonium trichloro(dioxoethylene-o,o')tellurate] was previously found to protect cancer patients from chemotherapy-induced bone marrow toxicity and alopecia. Here we show that AS101 induces hair growth in nude and normal mice. AS101 possesses the dual ability to both induce anagen and retard spontaneous catagen in the C57BL/6 mouse model. Anagen induced by AS101 is mediated by keratinocyte growth factor (KGF), as it is abrogated both in nude mice co-treated with AS101 plus neutralizing anti KGF antibodies and in AS101-treated transgenic mice expressing a dominant-negative KGF receptor transgene in basal keratinocytes. AS101 up-regulates KGF expression by activating the ras signaling pathway in cultured fibroblasts. AS101-induced delayed catagen is associated with inhibition of terminal differentiation marker expression both in nude and C57BL/6 mice epidermal follicular keratinocytes and in cultures of primary mouse follicular keratinocytes induced to differentiate. This activity is associated with relatively sustained elevation of p21waf. Delayed expression of terminal differentiation markers was not induced by AS101 in follicular keratinocytes from p21waf knockout mice. Because similar results were obtained with cultures of primary human keratinocytes and fibroblasts, preliminary case report studies revealed substantial hair growth when AS101 was topically applied on three adolescents who had remained alopeciac 1-2 years after chemotherapy. The results emphasize the unique mode of action of AS101 and highlight its potential clinical use for treating certain types of alopecia.

Production of the novel mesangial autocrine growth factors GDNF and IL-10 is regulated by the immunomodulator AS101.

Mesangial cell (MC) proliferation is essential for the pathogenesis and progression of various glomerular diseases. This study shows that glial cell line-derived neurotrophic factor (GDNF) and IL-10 are mesangial autocrine growth factors that play a pivotal role in rat MC proliferation in vitro. Downstream targets of GDNF signaling and their role in MC hyperplasia are identified. The phosphatidylinositol 3-kinase (PI3K) pathway and its downstream target NF-kappaB were found to mediate GDNF-induced MC mitogenesis. This pathway also mediates GDNF-induced decrease in the cyclin-dependent kinase inhibitor p27(kip1) expression, resulting in the increased formation of cyclin D1/cdk4 and cyclin E/cdk2 complexes, followed by hyperphosphorylation of retinoblastoma, a key event for G1 to S phase progression. IL-10 appears to be a more potent MC growth factor that negatively regulates GDNF expression. Indeed, its inhibition by the nontoxic tellurium anti-IL-10 compound, ammonium trichloro(dioxoethylene-o,o') tellurate (AS101), extensively decreased MC clonogenicity despite GDNF upregulation. Identification of the mesangial GDNF and IL-10 pathways as critical mediators of mesangial cell proliferation may provide another target for therapeutic intervention in certain glomerular diseases. In vivo animal studies using AS101, currently undergoing phase II clinical trials on cancer patients, are warranted to determine its potential in the management of glomerular diseases associated with mesangial cell proliferation.

Anti-IL-10 therapeutic strategy using the immunomodulator AS101 in protecting mice from sepsis-induced death: dependence on timing of immunomodulating intervention.

The role of IL-10 in experimental sepsis is controversial. The nontoxic immunomodulator, ammonium trichloro(dioxoethylene-o,o')tellurate (AS101) has been previously shown to inhibit IL-10 expression at the transcriptional level. In this study, we show that in mice subjected to cecal ligation and puncture (CLP), treatment with AS101 12 h after, but not before, CLP significantly increased survival of septic mice. This was associated with a significant decrease in serum IL-10 and in IL-10 secretion by peritoneal macrophages 24-48 h after CLP. At that time, the ability of these cells to secrete TNF-alpha and IL-1beta was restored in AS101-treated mice. The increased survival of AS101-treated mice was due to the inhibition of IL-10, since cotreatment with murine rIL-10 abolished the protective activity of AS101. AS101 increased class II Ag expression on peritoneal macrophages, severely depressed in control mice, while it did not affect the expression of class I Ags. This was accompanied by a significant elevation in the level of IFN-gamma secreted by splenocytes. Moreover, AS101 ameliorated bacterial clearance in the peritoneum and blood and decreased severe multiple organ damage, as indicated by clinical chemistry. Furthermore, myeloperoxidase levels in the liver and lung of AS101-treated mice, an indirect means of determining the recruitment of neutrophils, were significantly decreased. We suggest that nontoxic agents such as AS101, with the capacity to inhibit IL-10 and stimulate macrophage functions, may have clinical potential in the treatment of sepsis, provided they are administered during the phase of sepsis characterized by immune suppression.

Bone marrow stem cell protection from chemotherapy by low--molecular-weight compounds.

The stem cells of the bone marrow have the capacity for both self-renewal and derivation of all the blood cell lineages. Consequently, toxicity to these cells can result in neutropenia, agranulocytosis, thrombocytopenia, pancytopenia, or aplastic anemia. Many anticancer drugs adversely affect the bone marrow, and neutropenia is a common limiting factor in dose escalation. In this review, we discuss agents that appear to have potential as bone marrow sparing agents. Computerized catalogs of the National Library of Medicine and Medline were searched for reports on low-molecular-weight compounds that detailed effects on the hematopoietic progenitor cells. The most promising agents are the endogenous peptides p-glutamic acid-glutamic acid-aspartic acid-cysteine-lysine and acetyl-serine-aspartic acid-lysine-proline, and the exogenous compounds amifostine and ammonium trichloro[dioxoethylene-O,O']tellurate, but several others are also discussed. These compounds preserve stem cell function in the presence of antineoplastic drugs of diverse pharmacological classes, and they do so by various mechanisms of action. Their present status in clinical practice is also detailed. More needs to be learned about their mechanisms of action and therapeutic potential, but the results are encouraging for some of these compounds and more clinical trials should be expected.

Up-Regulation by Ammonium Trichloro(Dioxoethylene-0,0′) Tellurate (AS101) of Fas/Apo-1 Expression on B16 Melanoma Cells: Implications for the Antitumor Effects of AS101

It was recently reported that human and mouse melanoma cells express Fas ligand (FasL) but almost no Fas, which may contribute to their immune privilege. AS101 (ammonium trichloro(dioxoethylene-0,0')tellurate), a synthetic immunomodulator with minimal toxicity, was found to have antitumor effects in various tumor models. Our present study shows that AS101 has direct and indirect effects on tumor cells; AS101 inhibits the clonogenicity of B16 melanoma cells in vitro. Moreover, wild-type P53 expression, which is required for induction of Apo-1 expression, increased significantly in AS101-treated cells. We therefore investigated Fas expression in AS101-treated B16 cells and found that Fas, but not FasL, expression was significantly increased; moreover, Fas receptors were functional. Longer incubation with AS101 resulted in spontaneous apoptosis triggered by the Fas-FasL system. To explore the relationship of these results to the antitumor effects of AS101, we injected B16-F10 mouse melanoma cells into syngeneic C57BL/6 mice carrying the lpr mutation in the Fas gene and to gld mutant mice that lack functional FasL. Tumor development in control groups was lowest in the lpr mice, while no difference was observed between gld and wild-type mice. Among the AS101-treated groups, the most pronounced effect appeared in the lpr mice, while the lowest was seen in the gld mutant mice. Our study suggests that AS101 may render melanoma tumor cells more sensitive to Fas/FasL-induced apoptosis and may therefore have clinical potential.

Tellurium Compounds: Selective Inhibition of Cysteine Proteases and Model Reaction with Thiols

Ammonium trichloro(dioxoethylene-O,O‘)tellurate (AS101) is an organotellurium(IV) compound that exhibits immunomodulation activity. In light of the unique Te(IV)−thiol chemistry, it was tested as a...

Delay in the onset of systemic lupus erythematosus following treatment with the immunomodulator AS101: association with IL-10 inhibition and increase in TNF-alpha levels.

It has recently been found that in systemic lupus erythematosus (SLE), a multisystem inflammatory disorder characterized by autoantibody production and decreased cellular immune response, increased spontaneous production of IL-10 occurs. The immunomodulator AS101 (ammonium trichloro(dioxoethylene-0,0')tellurate) was previously shown to significantly decrease IL-10 levels in cancer patients and in murine models. This study shows that AS101 inhibits the development of SLE-related autoimmune pathological manifestations. AS101 decreased the spontaneous IL-10 production by mononuclear cells from SLE patients in vitro. In vivo, systemic injection of AS101 to SCID mice transplanted with mononuclear cells from SLE patients significantly decreased serum human IL-10 levels. There was also a decrease in all serum human Ig isotypes, in anti-dsDNA, and in anti-Sm Igs. In the New Zealand Black/New Zealand White/F1 model, AS101 significantly increased serum TNF-alpha and IFN-gamma while decreasing IL-10 levels; these changes were accompanied by a rapid decrease in anti-dsDNA and anti-ssDNA Igs. More importantly, continuous treatment of New Zealand Black/New Zealand White/F1 mice with AS101 for 6 mo led to the development of proteinuria in 30% of the treated mice compared with 100% in PBS-treated mice (p < 0.001). AS101 treatment reduced the level of immmune complex deposition in the glomeruli, prevented glomerular hypercellularity and mesangial expansion and led to a much smaller mean glomerular volume in treated mice (185 +/- 6 vs 428 +/- 47.103 microm3; p < 0.01). We suggest that treatment with a nontoxic immunomodulator such as AS101, previously used in phase II trials on cancer patients, may be an effective therapeutic approach for controlling SLE.

Predominance of TH1 response in tumor-bearing mice and cancer patients treated with AS101.

Several studies have recently suggested that the immune response to malignant growths is regulated by distinct patterns of type 2 cytokine production. These cytokines, regulating the cytotoxic T-lymphocyte response in patients with advanced cancers, may be associated with disease progression. Evidence suggests that the T Helper 1 (TH1) and T Helper 2 (TH2) types of reaction are reciprocally regulated in vivo. The immunomodulator AS101 (ammonium trichloro[dioxoethylene-O,O']tellurate) was found to stimulate mouse and human cells to proliferate and secrete a variety of cytokines. Clinical trials using AS101 on cancer patients are now in progress. The aim of this study was to evaluate the ability of AS101 to modulate TH1 and TH2 responses in tumor-bearing mice and in patients with advanced cancer. In addition, we investigated the association between the predominance of each type of response with the antitumoral effects of AS101. Mice into which Lewis lung carcinoma (3LL) had been transplanted (n = 221) and cancer patients (n = 13) were treated with AS101 on alternate days, at 10 micrograms/mouse intraperitoneally, or for the patients, at 3 mg/m2 intravenously. The types were sarcoma, melanoma, and colon, lung, ovarian, and renal cancers. Cytokine levels were determined by immunoassay kits and compared with the paired Student's t test: in mice, they were tested in spleen cell supernatants; in humans, in sera and mononuclear cell supernatants. The chi-squared test was used to compare tumor volumes. All P values represent two-sided tests of statistical significance. Our results show that treatment of mice and patients with AS101 results in a clear predominance in TH1 responses, with a concomitant decrease in the TH2-type response. This was reflected by a significant enhancement in interleukin 2 (IL-2) and interferon gamma (IFN gamma) levels (P < .01) paralleled by a substantial decrease in IL-4 and IL-10 (P < .01). Moreover, the concentration of IL-12 was significantly increased (P < .01) in AS101-treated patients who also showed enhanced levels of natural and lymphokine-activated killer cell-mediated cytotoxicity. The statistically significant increases in IL-2 and IFN gamma levels, paralleled by the pronounced decrease in IL-4 and IL-10 in the AS101-treated mice, were associated with its antitumoral effects. In addition, systemic cotreatment of 3LL-transplanted mice with AS101 and anti-IL-12 antibodies partly abrogated the antitumoral effect of AS101. Immunotherapy with AS101 enhances TH1 function while interfering with the TH2 response. This TH1 trend may be related to the antitumor effects of AS101. Isolation and characterization of a distinct cytokine pattern in patients with advanced cancer treated with AS101 may contribute to the development of intervention strategies using this compound.

Inhibition of B16 melanoma metastasis by the immunomodulator AS101

The immunomodulator ammonium trichloro (dioxyethylene-O-O')tellurate (AS101) has previously been found to induce secretion of various cytokines in mouse and human, which include interleukin-l, interleukin-2, colony-stimulating factor, interferon-gamma, tumor necrosis factor, etc. It also protects mice from lethal and sublethal effects of chemotherapy and irradiation. The present studies were designed to evaluate its effect on pulmonary metastasis following intravenous (i.v.) injection of mouse B16 melanoma cells on day 0 of the experiment. AS101, given 10 mu g/mouse intraperitoneally in 7 daily injections starting the day before B16 cell infusion (day -1) led to a significant inhibition by 60%. When B16 cells were pretreated with AS101 for 24 h before injection, the lung metastases were further reduced by subsequent AS101 treatment of the tumor-loaded mice. In mice that had been depleted of natural killer (NK) cells using anti-asialo-GM1 antisera, AS101 was deprived of its stimulatory effect on the NK activity. The inhibition by AS101 on the B16 lung metastasis was also profoundly reduced by the antisera. Moreover, in vitro treatment of B16 cells with AS101 resulted in suppression of the cell growth in a semisolid culture. This was accompanied by an inhibition of the DNA synthesis and a dephosphorylation/activation of the retinoblastoma susceptibility protein (RE), a tumor suppressor gene product, in the B16 cells. Taken together, these data suggest that AS101 possesses an anti-metastatic activity, which probably involves two mechanisms: the stimulation of the host NK cell activity and the inhibition of the tumor cell proliferation.

Differential effect of the immunomodulator AS101 on B7-1 and B7-2 costimulatory molecules: role in the antitumoral effects of AS101.

The CD28 receptor on T cells with its ligand B7, representing the best characterized example of costimulation, has recently been demonstrated to interact with two different ligands: B7-1 and B7-2. AS101 (ammonium trichloro[dioxoethylene-O,O']tellurate), a synthetic immunomodulator with minimal toxicity, was previously shown to stimulate both mouse and human cells to proliferate and secrete a variety of cytokines. We recently found that treatment of advanced cancer patients or tumor-bearing mice with AS101 results in a clear predominance of Th1 responses with a concomitant decrease in Th2 response. Our present study demonstrates that AS101 differentially affects B7-1 and B7-2 molecule expression on mouse macrophages: it up-regulates B7-1 expression in a dose-dependent manner without affecting B7-2 expression, which leads to a profound macrophage costimulatory activity of purified T cells with soluble anti-CD3. Our results also demonstrate the differential inhibitory effect of IL-10 on T cell activation in the presence of AS101-stimulated accessory cells (AC). We show that when stimulated with AS101, AC-dependent T cell activation was more resistant to inhibition by IL-10 compared with AC stimulated by LPS. This was due to the partial resistance of AS101-stimulated macrophages to the down-regulation of B7-1 expression by IL-10. In vivo studies with AS101-treated tumor-bearing mice revealed that the predominance in Thl responses--marked by an increase in IFN-gamma and a decrease in IL-4--may be associated in part with the ability of AS101 to up-regulate B7-1 expression, which is also related to its antitumoral effects. These results suggest that AS101 may be clinically effective in conditions involving dysfunctional cytokine production.

The antitumoral effect of the immunomodulator AS101 and paclitaxel (Taxol) in a murine model of lung adenocarcinoma.

The immunomodulator ammonium trichloro(dioxyethylene-0-0')tellurate (AS101) has been shown to possess antitumoral properties in several murine models. In the present study, we demonstrate a synergistic in vivo antitumor effect of AS101 and Taxol against early stage Madison 109 lung adenocarcinoma. Treatment with optimal doses of Taxol (25 and 17 mg/kg) and AS101 (0.5 mg/kg) resulted in 66.6 and 43.3% cures. We propose that the antitumor effect is the result of both a direct and indirect effect of the drugs on tumor cells. AS101 and Taxol directly inhibited clonogenicity of M109 cells in a synergistic dose-dependent manner. Exposure of M109 cells to clinically achievable concentrations of Taxol and AS101 produced a synergistic internucleosomal DNA fragmentation associated with programmed cell death. We suggest that AS101 renders tumor cells more susceptible to chemotherapy in general and to Taxol in particular, partly by increasing the wild-type p53 protein expression that is required for efficient execution of the death program. Moreover, we demonstrate a synergistic effect of AS101 and Taxol in increasing the tumoricidal activity of macrophages. This activity is produced by nitric oxide secretion. The synergistic antitumoral effects of AS101 and Taxol were partly ablated both in vitro and in vivo by inhibition of nitric oxide synthase. These findings indicate that AS101 in combination with Taxol may be a promising antitumor drug, and illustrate the mechanism of action of both drugs when acting synergistically. Phase II clinical trials have been initiated using AS101 in combination with Taxol.

584 Mesothelioma: Treatment with a new immunomodulator—AS101

Previous studies with AS101 (ammonium trichloro[dioxyethylene-0, 0’]tellurate) have shown it to have significant immunostimulatory and tumoricidal effects with minimal toxicity. Nineteen consecutive patients with malignant mesothelioma were entered into protocol using AS101 at 3 mg/m2, I.V., three times a week. Males (13) predominated, the median age was 50 years (range 30–72). Seven patients were heavily pretreated. Median number of treatments was 10+ weeks (wks) with a range of 3–136 + wks. One patient had a CR (136 + wks), one had a PR (48 wks), and one a minimal response (39 + wks). All responding patients were previously treated with chemotherapy with no response and with progressive disease. Side effects included halitosis (14) and fever spikes (4). We conclude that AS101 is a promising agent in the treatment of mesothelioma and plan further studies in combination with chemotherapy.

Role of Endogenous Cytokines Secretion in Radioprotection Conferred by the Immunomodulator Ammonium Trichloro(dioxyethylene-0-0')tellurate

The immunomodulator ammonium trichloro(dioxyethylene-0-0')tellurate (AS101) has previously been found by us to have radioprotective properties when injected into mice before sublethal and lethal doses of irradiation. AS101 also was found to protect mice from hematopoietic damage caused by various chemotherapeutic drugs. Based on these findings, phase II clinical trials with cancer patients treated with AS101, in combination with chemotherapy, are currently underway. In the present study, we wanted to assess the role of several cytokines in the radioprotection conferred by AS101. We show that the administration of neutralizing antibodies against interleukin-1 (IL-1) receptor, IL-6 receptor, IL-6, tumor necrosis factor (TNF), or stem cell factor (SCF) completely abrogates the ability of AS101 to increase the survival of lethally irradiated mice. Moreover, the injection of each of these antibodies reduces the ability of AS101 to increase the number of BM, spleen cells, and the number of circulating neutrophils, lymphocytes, and platelets in irradiated mice. In addition, these antibodies abrogate the enhancing effect of AS101 on the secretion of IL-3, IL-6, and granulocyte-macrophage colony-stimulating factor, all of which decrease significantly in sublethally irradiated mice. By contrast, the injection of anti-IL-2 receptor antibody or control Igs to AS101-treated mice does not interfere with the radioprotective effects of the compound. These results suggest a role for IL-1, IL-6, TNF alpha, and SCF in the radioprotective effect of AS101. Because cytokine toxicity remains a significant concern, the clinical application of AS101, which has no toxicity, is particularly valuable.

Induction of acute phase proteins in mice and humans by treatment with AS101, an immunomodulator with radioprotective properties

AS101 (ammonium trichloro(dioxyethylene-0,0′)tellurate) is a new synthetic compound previously described by us as having immunomodulating properties and minimal toxicity. Phase II clinical trials are currently in progress with AS101 on cancer patients. AS101 has been recently found to have both radioprotective and chemoprotective effects on hemopoiesis of irradiated mice or mice treated with various chemotherapeutic drugs. The present research was designed to study the in vivo induction of liver acute phase proteins secretion in mice or patients treated with AS101. Induction of these proteins, some of which have the capacity to scavenge free radicals, may contribute to radioprotection. We present evidence that treatment with the immunomodulator AS101 increases production of a variety of acute phase proteins. We demonstrate a significant elevation of serum amyloid A (SAA) in sera of treated mice, as well as an increase in SAA, factor B and ceruloplasmin in sera of patients treated with AS101. The same AS101 treatment was shown to decrease the amount of the negative acute phase protein, albumin. In addition we show that IL-1, IL-6 and TNF-α are important mediators of changes in SAA concentrations induced by AS101. Abrogation of SAA production in AS101 treated mice by any one of the and IL-1R, IL-6R or TNF-α antibodies indicates that at least in mice, SAA production is not controlled by a single extracellular signal, but rather it is regulated, at the least, by all three cytokines in various combinations. A better understanding of the mechanism by which AS101 confers radioprotection will enable us to use it more effectively in the restoration of hemopoiesis in patients following radiation or suffering from overdose or accidental radiation.

Restoration of murine cytomegalovirus (MCMV) induced myelosuppression by AS101

Infection with cytomegalovirus (CMV) continues to be one of the most common complications following allogeneic bone marrow transplantation. The gravest danger for the host occurs when the virus is reactivated as a result of immunosuppression. In this report we studied the effects of sublethal murine cytomegalovirus (MCMV) infection on the hemopoietic system including bone marrow (BM) cellularity, production of colony stimulating factor (CSF) and interleukin-6 (IL-6) and the development of granulocyte-macrophage colony forming units (CFU-GM), and BM stromal cell viability. Our findings show that the virus infection led to a significant decrease in the number of BM cells and in the production levels of CSF and IL-6. There was also a decrease in the number of stromal cells, as reflected by the number of colony forming unit fibroblasts (CFU-F), and in the relative number of CFU-GM progenitors. Treatment of MCMV infected mice with the immunomodulator AS101 [ammonium trichloro (dioxyethylene 0-0′)tellurate] restored significantly CSF and IL-6 production by BM cells to levels of uninfected control mice as well as the number of CFU-F and stromal cell elements which consequently led to the restoration of the total number of BM cells. Results presented here indicate that AS101 may have immunomodulatory effects on MCMV mediated myelosuppression. Administration of AS101 to patients with CMV associated BM damage may improve the restoration of their BM function.

Ocular inflammation stimulated by the immunomodulator AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate

The purpose of this study was to investigate the effect of a novel immunomodulator, AS101 [ammonium trichloro(dioxyethelene-O-O') tellurate], in the eye. Lewis rats were injected intravitreally with AS101 at a concentration of 13 micrograms/ml in one eye and BSS in the contralateral eye. Control animals were injected with BSS into the central vitreous of both eyes. Ocular inflammation was evaluated at 20 hours by histology, immunopathology, and by cell count, protein and cytokine measurement in the aqueous humor. At 20 hours, eyes injected with AS101 developed iridocyclitis and mild vitritis versus minimal inflammation and/or protein in contralateral eyes or eyes of control animals (p = 0.0121). The inflammatory infiltrate was mixed in character. Major Histocompatibility Complex (MHC) class II antigens and intercellular adhesion molecules (ICAM-1) were expressed in the anterior segment of eyes injected with AS101. In the aqueous humor of these eyes there were significant quantities of inflammatory cells, protein (mean +/- SEM = 11.2 +/- 2.3 mg/ml) and the cytokine interleukin 6 (IL-6) (450 units/ml) compared with contralateral eyes (p = 0.0005 for inflammatory cells; protein, mean +/- SEM = 1.6 +/- 0.17 mg/ml; IL-6 = 12 units/ml) and both eyes of control animals injected with BSS (p = 0.8955 for inflammatory cells; protein, OD = 1.5 mg/ml, OS = 0.7 mg/ml; IL-6, OD = 8 units/ml, OS = 13 units/ml). AS101 has a local inflammatory effect in the eye. This compound may activate ocular inflammation by releasing cytokines such as IL-6.

Influence of secondary bonding on the intradimer distance of trichloro(ethane-1,2-diolato-O,O′)tellurate(IV)

The structure of ammonium trichloro(ethane-1,2-diolato-O,O′)tellurate(IV) was determined by single-crystal methods: monoclinic, space group P21/c(no. 14), a= 10.779(1 ), b= 12.418(2), c= 6.915(1)A, β= 108.65(1)°. The co-ordination around TeIV is distorted ψ octahedral with one of the two oxygen atoms lying opposite to the lone pair of Te. Two identical anions form a dimeric unit via a centre of symmetry. A short Te–O intradimeric distance of 2.764(6)A is about 0.84 A shorter than the sum of the corresponding van der Waals radii. The structure is compared with that of the corresponding tetraphenylphosphonium salt where the intradimer distance is clearly longer. The size of the cation and the amount of intermolecular interactions seem to be decisive factors in secondary bonding between two anionic units. The electronic properties of the anions in the two salts were investigated by ab initiocalculations and compared with those of the optimised structure of the corresponding monomeric anion. The positive charge of 1.36 electrons at Te is almost invariable. The main interaction within a dimeric unit in the ammonium salt is a donation of an electron pair from oxygen to the antibonding molecular orbital between Te–Cl in the neighbouring anion. The bond between Te and one of the equatorial Cl atoms (opposite to oxygen) is sensitive to dimerisation. The charge density, ionic nature of the bond and bond length increase when the degree of dimerisation increases, whereas the other two Te–Cl bonds are almost insensitive.