COX-2 and prostanoid expression in micturition pathways after cyclophosphamide-induced cystitis in the rat

The purpose of this study was to determine the role of cyclooxygenase-2 (COX-2) and its metabolites in lower urinary tract function after induction of acute (4 h), intermediate (48 h), or chronic (10 day) cyclophosphamide (CYP)-induced cystitis. Bladders were harvested from euthanized female rats for analyses. Conscious cystometry was used to assess the effects of a COX-2-specific inhibitor, 5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulfonyl)phenyl2(5H)-furanone (DFU, 5 mg/kg sc), a disubstituted furanone, in CYP-induced cystitis. COX-2 mRNA was increased in inflamed bladders after acute (12-fold) and chronic (9-fold) treatment. COX-2 protein expression in inflamed bladders paralleled COX-2 mRNA expression. Prostaglandin D2-methoxime expression in the bladder was significantly (P < or = 0.01) increased in acute (3-fold) and chronic (5.5-fold) cystitis. Prostaglandin E2 was significantly (P < or = 0.01) increased (2-fold) in the bladder with intermediate (1.7-fold) and chronic (2.6-fold) cystitis. COX-2-immunoreactive cell profiles were distributed throughout the inflamed bladder and coexpressed histamine immunoreactivity. Conscious cystometry in rats treated with CYP + DFU showed increased micturition intervals 4 and 48 h after CYP treatment and decreased intravesical pressures during filling and micturition compared with rats treated with CYP + vehicle. These studies suggest an involvement of urinary bladder COX-2 and its metabolites in altered micturition reflexes with CYP-induced cystitis.

Anti-HIV activity of the combination of didanosine and hydroxyurea in HIV-1-infected individuals

HIV is known to be present in massive amounts in both resting and actively replicating cells in infected individuals. We tested the combination of didanosine and hydroxyurea, known to suppress viral production in vitro in both of these cell types, in a small number of asymptomatic patients. After 3 months of well tolerated treatment, we observed a large reduction of viral load in the peripheral blood of all 12 patients, down to nonquantifiable levels in 7 of 12 as measured by infectious virus titer, and 6 of 12 as measured by plasma HIV-RNA. In this subgroup of 6 patients, whose baseline HIV-RNA was below 14,000 copies/ml, the median increase in CD4+ count after 90 days of treatment was 244 cells/mm3.

Antiproliferative effect of D-aspartic acid beta-hydroxamate (DAH) on Friend virus-infected erythropoietic progenitor cells

D-aspartic beta-hydroxamate (DAH), an aspartic acid analog, exerts antitumoral activity on murine leukemia L5178Y, both in vitro and in vivo. In this study, we show that DAH is also active in vivo against Friend virus (FV-P)-induced erythroleukemia, and we report the effects of DAH in vivo an in vitro on FV-P target cells, i.e. the mature erythroid colony-forming cells (CFU-E). DAH treatment (2 g/kg/day) given for 95 days as a single daily i.p. injection to DBA/2 mice either 3 or 12 days following inoculation with a high dose (10(3) plaque-forming units) of FV-P resulted in a marked increase in the mean survival time of treated animals (212 and 191%, respectively). Since FV-P elicits spleen enlargement and polycythemia, we examined the effects of DAH on spleen size, spleen-nucleated cell number, and hematocrit, in normal and FV-P infected mice, at different times in the course of continuous DAH treatments. DAH treatment initiated 3 days after viral infection inhibits the virus-induced splenomegaly, with at day 26 p.i. 1.15 x 10(8) and 12.6 x 10(8) nucleated cells per spleen observed in DAH-treated mice and untreated mice respectively, whereas only 1.03 x 10(8) nucleated cells were observed in uninfected mice. Furthermore, DAH prevents virus-induced polycythemia: on day 26, an hematocrit of 39% was measured in DAH-treated mice as compared to 60% in untreated mice. DAH treatment initiated 12 days after viral infection reduces splenomegaly, the number of nucleated spleen cells and the hematocrit of infected mice. DAH treatment initiated 3 days after viral infection prevents the tremendous increase of CFU-E in the spleen of infected mice: on day 11, the spleen of infected mice contained 4.6 x 10(6) CFU-E, while the spleen of treated mice only contained 26 x 10(3) CFU-E, and on day 26 the spleen CFU-E numbers were 45.4 x 10(6) and 1.5 x 10(6) in untreated and treated infected mice, respectively. In control uninfected mice, DAH treatment induced a transient decrease in spleen CFU-E followed by a rebound phenomenon. In vitro, preincubation with DAH inhibits colony formation by FV-P infected CFU-E, at doses starting at 3 mM, as compared to uninfected CFU-E. These data show that DAH inhibits the expression of the retroviral infection, and appears to preferentially inhibit the proliferation of infected target cells (CFU-E) in vivo.

Therapeutic effects of D-aspartic acid beta-hydroxamate (DAH) on Friend erythroleukemia

D-aspartic acid beta-hydroxamate (DAH), an aspartic acid analogue, exerts anti-tumoral activity against murine leukemia L5178Y both in vitro and in vivo. We show here that DAH displays activity against Friend leukemia cells (FLC) in vitro: a concentration of 2 mM results in a total inhibition of cell growth. DAH is also active in vivo against Friend virus (FV-P)-induced erythroleukemia. Treatment with DAH, given for 95 days as a single daily i.p. injection to DBA/2 mice 3 days following FV-P inoculation, induced a marked increase of 212% in the mean survival time (MST) of treated animals. Since FV-P-induced erythroleukemia is characterized by the proliferation of mature erythroid precursors, we examined the effect of DAH treatment on erythroid colony-forming cells (CFU-E) and observed that the number of CFU-E per spleen was 30 times lower in DAH-treated mice than in the controls. To gain further insight into the early effects of DAH treatment on the early phase of Friend disease, we examined the effects of short DAH treatment on spleen size, hematocrit and viremia in FV-P-infected mice. DAH treatment initiated 3 days post infection (p.i.) inhibited splenomegaly, prevented virus-induced polycythemia, and reduced serum viremia. Late DAH treatment (18 days p.i.) induced regression of FVP-induced disease as evidenced by reduction of spleen weight.

Selective cytotoxicity of L-glutamic acid gamma-monohydroxamate (GAH) for melanoma tumor cells

We have previously shown that L-glutamic acid gamma-monohydroxamate (GAH) exhibits an antitumor activity, both in vitro and in vivo. In this report we explore the selective cytotoxicity of GAH in vitro by comparing the survival of tumor and normal cells. GAH exerts an irreversible delayed effect with tumoral cells and a reversible effect with normal cells: after a short incubation time of 6 hrs in the presence of 1.2 mM GAH and after removal of the drug, the survival of N Ter Dau and MRC5 cells was identical reaching about 85% after 24 hrs of culture. But, after another 48 hrs of culture, MRC5 cells recovered 100% cell survival while with N Ter Dau cells the survival decreased to 65%. A longer exposure time to GAH (18 hrs) and an additional 54 hrs of culture after removal of GAH led to 50 +/- 10% of cell survival with normal cells but only 25 +/- 10% with tumor cells. Using a long-term clonogenic assay, we showed that the 25% N Ter Dau cells surviving at 72 hrs after GAH treatment led mainly to abortive colonies (17% +/- 3%) with only 2.3 +/- 0.9% of surviving colonies. Such a difference does not exist for normal cells. Cell cycle analysis of tumor and normal cells treated with GAH (18 hrs, 1,2 mM) has shown that the drug prevents both cell type from cycling from G1 to S phase. However, the two cell types started to cycle again after removal of GAH but a delay of 24 hrs was observed for tumoral cells compared to normal cells.

Anti-tumoral activity of L and D isomers of aspartic acid beta-hydroxamate on L5178Y leukemia

D and L isomers of aspartic acid beta-hydroxamate (respectively DAH and LAH) were compared for their in vitro and in vivo activity against the murine leukemia L5178Y and their tolerance in vivo in DBA/2 mice. DAH and LAH displayed comparable cytotoxic activity against L5178Y leukemia in vitro. Death of leukemia cells was observed at concentrations above 1.2 mM for both DAH and LAH. High concentrations of L-asparagine partially reversed the growth-inhibitory effects of DAH and LAH on L5178Y cells for concentrations of DAH and LAH lower than 0.6 mM. Intraperitoneal administration of DAH and LAH to mice showed that the LD10, LD50 and LD90 of DAH was 3- to 4-fold greater for DAH than for LAH. DAH was able to eradicate L5178Y tumors in mice without inducing toxic deaths, whereas LAH at comparable doses killed all the animals treated.