The prognostic value of the cardiopulmonary exercise test in patients with heart failure who have been treated with beta-blockers.

OBJECTIVES: The prevalence of chronic heart failure and a reduced ejection fraction (CHF-REF) has increased over the last decade. The cardiopulmonary exercise test (CPET) is an established tool for managing these patients. For patients who are administered beta-blockers, its predictive value is debated. The aim of this study was to assess the prognostic values of several parameters in patients with CHF-REF who were on beta-blockers. STUDY DESIGN: 390 patients with CHF-REF underwent CPET after cardiac rehabilitation and were followed for two years. RESULTS: The primary endpoints were all-cause mortality, cardiac-related mortality and major cardiovascular events (hospitalization for HF, heart transplantation and acute coronary syndrome or arrhythmia). The mean beta-blockers dosage was 68.9% of the target dose. The two-year mortality rate was 13%, while the mean age of the population was 57.1 years. In addition, most of the patients were men (85.5% vs. 14.5%). The resting LVEF was 35.7 ± 9.4 and the maximal oxygen uptake (peak VO2) was 19.5 ml/kg/min. The peak VO2, VE/VCO2 slope and circulatory power were significant predictors of risk. The prognosis was better when the initial linear VE/VCO2 slope was lower than 30, and the final steeper VE/VCO2 slope was lower than 32. There was no difference between the two slopes. The oxygen uptake efficiency slope, oxygen uptake, heart rate recovery, VE/VCO2/VO2 index and ventilatory threshold had no prognostic value. CONCLUSION: The peak VO2, circulatory power and VE/VCO2 slope were prognostic indicators for patients with CHF-REF who were on beta-blockers.

Characterization of humoral and cellular immune responses in mice induced by immunization with HIV-1 Nef regulatory protein encapsulated in poly(DL-lactide-co-glycolide) microparticles.

We have characterized the humoral and cellular immune responses of BALB/c mice immunized with HIV-1 Nef regulatory protein encapsulated in poly(DL-lactide-co-glycolide) PLG particles. Three groups of mice were immunized with Nef PLG, Nef in the presence of complete Freund's adjuvant (CFA) or Nef alone in PBS. When titers were compared 7 months after the last injection, anti-Nef titers in mice immunized with Nef PLG were still close to the maximum, whereas a significant decrease was observed in mice immunized with Nef alone (five times lower) or with Nef in CFA (three times lower). These results indicate that Nef PLG is at least a similar or better vector/adjuvant than Nef in CFA concerning the duration of the humoral immune response. The analysis of cytokine profiles (IL-5 and IL-10) and the isotypic patterns of anti-Nef antibodies (predominantly IgG1), in the three groups of mice, indicated a predominant Th2 immune response. Using synthetic peptides covering the entire sequence of Nef, we identified at least three linear epitopes within sequences 32-64, 118-167 and 185-205 in the sera of mice immunized with Nef PLG or Nef CFA. In contrast, anti-Nef antibodies against Nef alone failed to recognize synthetic peptides, indicating that the majority of anti-Nef antibodies were primarily directed against conformational epitopes. We then examined the ability of Nef PLG to prime for the antigen-specific proliferative responses in vitro. The data obtained indicate the presence of both B-cell and T-cell epitopes in the C-terminal fragment of the protein after immunization of mice with Nef encapsulated in PLG particles.

Effects of curcumin and curcumin derivatives on mitochondrial permeability transition pore.

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is a natural compound with antiproliferative properties. Recent studies suggest that these properties might be due to the ability of curcumin to induce apoptosis in tumor cells by increasing the permeability of the mitochondrial membrane. In the present study, we confirm these observations and provide a molecular mechanism for the action of curcumin in rat liver mitochondria. Curcumin induced mitochondrial swelling, the collapse of Deltapsi, and the release of cytochrome C, events associated with the opening of the permeability transition pore (PTP). Experiments were performed with chemically substituted curcumin derivatives. Some derivatives were obtained by modification of groups on the terminal aromatic rings, and others were obtained by substitution of the diketone function with the cyclohexanone function. They demonstrated that phenol and methoxy groups were essential to promote PTP opening. Curcumin and curcumin derivatives that open the PTP were able to oxidize thiol groups. In addition, PTP opening was abolished in medium devoid of O2 and decreased in the presence of catalase, ferrozine, o-phenanthroline, mannitol, or N-ethylmaleimide. These data suggest that the mechanism by which curcumin promotes PTP opening involves the reduction of Fe3+ to Fe2+, inducing hydroxyl radical (HO*) production and oxidation of thiol groups in the membrane, leading to pore opening.

Fluoride curcumin derivatives: new mitochondrial uncoupling agents.

The mitochondrial effects of two fluoride curcumin derivatives were studied. They induced the collapse of mitochondrial membrane potential (DeltaPsi), increased mitochondrial respiration, and decreased O(2)*- production and promoted Ca(2+) release. These effects were reversed by the recoupling agent 6-Ketocholestanol, but not by cyclosporin A, an inhibitor of the permeability transition pore (PTP), suggesting that these compounds act as uncoupling agents. This idea was reinforced by the analysis of the physico-chemical properties of the compounds indicating, that they are mainly in the anionic form in the mitochondrial membrane. Moreover, they are able to induce PTP opening by promoting the oxidation of thiol groups and the release of cytochrome c, making these two molecules potential candidates for induction of apoptosis.

Biologic evaluation of curcumin and structural derivatives in cancer chemoprevention model systems.

Curcumin is a natural product widely used as a spice in food. It has been shown to inhibit cyclooxygenase (COX)-1 and -2 and to suppress lipopolysaccharide-induced COX-2 and iNOS gene expression. In the present study, curcumin and 22 of its derivatives were evaluated for their chemopreventive potential. Based on COX-2 inhibition, curcumin (IC50=15.9 microM), 1,7-bis(3-fluoro-4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (19) (IC50=23.7 microM) and 2,6-bis(3-fluoro-4-hydroxybenzylidene)cyclohexanone (23) (IC50=5.5 microM) were found to be most potent. Tricyclic derivatives 2,6-bis(4-hydroxy-3-methoxybenzylidene)cyclohexanone (10), 2,6-bis(4-hydroxy-3,5-dimethoxybenzylidene)cyclohexanone (13) and 2,5-bis(4-hydroxy-3,5-dimethoxybenzylidene)cyclopentanone (21) inhibited LPS-induced COX-2 and iNOS gene expression in murine macrophages with potency equal to curcumin. RT-PCR experiments demonstrated suppression of COX-2 and iNOS gene expression occurred at the transcriptional level. The most active compounds in the macrophage assays, 13 and 23, were also the most cytotoxic, however. Topical application of curcumin, 10, 13, 21, and 6, a methoxy derivative of curcumin, showed strong inhibition of 12-O-tetradecanoyl-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity in mouse skin. These data suggest that structural elements responsible for COX-1 and COX-2 inhibition do not correlate well with those responsible for inhibiting COX-2 and iNOS gene expression, but elements capable of inhibiting COX-2 and iNOS gene expression also contribute to inhibition of TPA-induced ODC activity. The most potent compounds in these assays, 10, 13 and 21, as well as curcumin, were further evaluated for inhibition of 7,12-dimethylbenz(a)anthracene (DMBA)-induced preneoplastic lesion formation in a mouse mammary organ culture model, and dose-dependent responses were observed. Most potent effects were at concentrations between 1 and 5 microM for 10, 13 and 21, and at 10 microM for curcumin. These data demonstrate the substitution pattern on the aromatic moiety is especially crucial for activity.

Quantitative determination of loadings and oxidation products of polystyrene-bound phosphines using 31p MAS NMR.

The use of (31)P magic angle spinning (MAS) NMR for the quantitative determination of resin loadings and the building up of oxidation products was investigated. Loadings of polystyrene-bound phosphines were evaluated via addition of triphenyl phosphate as reference compound. Results for a series of phosphines are consistent with those obtained from well-established analytical methods. The compounds were also investigated with (13)C MAS NMR, and the individual oxidation stabilities were monitored under oxygen atmosphere.