Biomedical subjects

T Duarte

Publications and source records attributed to T Duarte.

4 recordsLinked to original sources

PubMed2002

Butyrate induces apoptosis in murine macrophages via caspase-3, but independent of autocrine synthesis of tumor necrosis factor and nitric oxide.

We demonstrated that 4 mM butyrate induces apoptosis in murine peritoneal macrophages in a dose- and time-dependent manner as indicated by studies of cell viability, flow cytometric analysis of annexin-V binding, DNA ladder pattern and the determination of hypodiploid DNA content. The activity of caspase-3 was enhanced during macrophage apoptosis induced by butyrate and the caspase inhibitor z-VAD-FMK (100 microM) inhibited the butyrate effect, indicating the major role of the caspase cascade in the process. The levels of butyrate-induced apoptosis in macrophages were enhanced by co-treatment with 1 microg/ml bacterial lipopolysaccharide (LPS). However, our data indicate that apoptosis induced by butyrate and LPS involves different mechanisms. Thus, LPS-induced apoptosis was only observed when macrophages were primed with IFN-gamma and was partially dependent on iNOS, TNFR1 and IRF-1 functions as determined in experiments employing macrophages from various knockout mice. In contrast, butyrate-induced macrophage apoptosis was highly independent of IFN-gamma priming and of iNOS, TNFR1 and IRF-1 functions.

Amino Acid Chloromethyl Ketones↗

PubMed2000

Oxovanadium(IV) complexes with aromatic aldehydes.

The synthesis, structure and spectroscopic properties of complexes with the formula [V(IV)O(dsal)2(H2O)], where Hdsal = salicylaldehyde, o-vanillin and 3-ethoxysalicylaldehyde, are presented. The crystal and molecular structures of [V(IV)O(o-van)2(H2O)] (1) (o-Hvan = o-vanillin = 3-methoxysalicylaldehyde) is studied by single-crystal X-ray diffraction. Each molecule exhibits an octahedral geometry with the two o-van ligands coordinated cis to the V(IV)O2+ group. 1 is the first example of a structurally characterized vanadium complex involving O(aldehyde) as the donor atom and this enables a comparison between the bonding characteristics and the contributions of O(aldehyde), O(amide), O(carboxylate) and O(ketone) (in acetylacetone) to the parallel hyperfine coupling constant in VOL2 complexes.

Aldehydes↗

PubMed2000

Construction of a branched chain at C-3 of a hexopyranoside. Synthesis of miharamycin sugar moiety analogs.

Synthesis of the conveniently protected epimer at C-3' of the miharamycin sugar moiety was accomplished starting from the corresponding 3,3'-spiroepoxide. Reaction of the epoxide with lithium cyanide, followed by hydrolysis and spontaneous cyclization, afforded the intermediate deoxylactone methyl 4,6-O-benzylidene-3-C-(carboxymethyl)-alpha-D-glucopyranoside-3',2-lacto ne (8). Stereoselective hydroxylation with MoO5 x py x HMPA, reduction with lithium aluminum hydride and cyclization with diethyl azodicarboxylate-triphenylphosphine gave the target molecule methyl 2,3''-anhydro-4,6-O-benzylidene-3-C-[(R)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside (5). Direct reduction of 8 gave other analogs having no C-3' hydroxyl group together with having a C-3'' hydroxyl group (hemiacetal). In addition, C-3' epimers were also synthesized through C-3', C-3'' dihydroxy analogs. Wittig reaction of an appropriate ketosugar with [(ethoxycarbonyl)methylene]triphenylphosphorane leading to a 7:3 Z/E mixture, followed by hydroxylation with osmium tetroxide, reduction and cyclization afforded the target molecule 5 and the miharamycin sugar moiety methyl 2,3''-anhydro-4,6-O-benzylidene-3-C-[(S)-1,2-dihydroxyethyl]-alpha -D-glucopyranoside. Examination of X-ray data for 5 and its NMR spectroscopy data allowed us to explain a contradiction reported in the literature.

Anti-Bacterial Agents↗

PubMedDate not supplied

[Pregnant rats consuming diets with uncooked and fried olive oil, mineral levels in their offspring and changes in their body storage levels].

Some parameters relating nutritional utilization of Ca, Mg, Fe and Zn were studied in rats fed with diets including raw and fried fats in order to study more in depth the diet fat/mineral utilization interaction. Wistar rats having initial weights of 176 g were divided into two groups and fed isocaloric diets having 15% fat content as raw olive oil and fried olive oil (from 15 potato fryings), during pregnancy. Weight and dietary intake were controlled and mineral content changes in plasma, liver, spleen and carcass were assessed, as well as litter mineral uptake. Throughout the study, dietary intake of pregnant rats fed raw (R) and fried oil (F), body weight gain and final weight gain were similar. Serum Fe, Zn and Ca levels decreased at a similar rate in both groups. Liver Fe levels decreased more in the F group while spleen Fe decreased more in the R group, these changes started on day 18. Liver Zn levels did not show clear changes but spleen Zn decreased during the last three days of pregnancy. Carcass Ca levels of pregnant rats from the R and F groups did not show any differences at the end of pregnancy. Body weight gain, Ca, Mg, Fe and Zn uptake of the litter were similar in both groups throughout the study. The placentas and the offspring of treated rats showed similar absolute and relative mineralization values. These findings lead us to conclude that fried olive oil retained the same characteristics as raw olive oil regarding mineral utilization.

Animals↗