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R Delgado

Publications and source records attributed to R Delgado.

At least 19 recordsLinked to original sources
PubMed2002

Modulation of rat macrophage function by the Mangifera indica L. extracts Vimang and mangiferin.

Vimang is an aqueous extract of Mangiferia indica L., traditionally used in Cuba as an anti-inflammatory, analgesic and antioxidant. In the present study, we investigated the effects of Vimang and of mangiferin (a C-glucosylxanthone present in the extract) on rat macrophage functions including phagocytic activity and the respiratory burst. Both Vimang and mangiferin showed inhibitory effects on macrophage activity: (a) intraperitoneal doses of only 50-250 mg/kg markedly reduced the number of macrophages in peritoneal exudate following intraperitoneal injection of thioglycollate 5 days previously (though there was no significant effect on the proportion of macrophages in the peritoneal-exudate cell population); (b) in vitro concentrations of 0.1-100 microg/ml reduced the phagocytosis of yeasts cells by resident peritoneal and thioglycollate-elicited macrophages; (c) in vitro concentrations of 1-50 microg/ml reduced nitric oxide (NO) production by thioglycollate-elicited macrophages stimulated in vitro with lipopolysaccharide (LPS) and IFNgamma; and (d) in vitro concentrations of 1-50 microg/ml reduced the extracellular production of reactive oxygen species (ROS) by resident and thioglycollate-elicited macrophages stimulated in vitro with phorbol myristate acetate (PMA). These results suggest that components of Vimang, including the polyphenol mangiferin, have depressor effects on the phagocytic and ROS production activities of rat macrophages and, thus, that they may be of value in the treatment of diseases of immunopathological origin characterized by the hyperactivation of phagocytic cells such as certain autoimmune disorders.

Adjuvants, Immunologic↗
PubMed2001

Albumin-derived advanced glycation end-products trigger the disruption of the vascular endothelial cadherin complex in cultured human and murine endothelial cells.

Endothelial cell (EC) junctions regulate in large part the integrity and barrier function of the vascular endothelium. Advanced glycation end-products (AGEs), the irreversibly formed reactive derivatives of non-enzymic glucose-protein condensation reactions, are strongly implicated in endothelial dysfunction that distinguishes diabetes- and aging-associated vascular complications. The aim of the present study was to determine whether AGEs affect EC lateral junction proteins, with particular regard to the vascular endothelial cadherin (VE-cadherin) complex. Our results indicate that AGE-modified BSA (AGE-BSA), a prototype of advanced glycated proteins, disrupts the VE-cadherin complex when administered to ECs. AGE-BSA, but not unmodified BSA, was found to induce decreases in the levels of VE-cadherin, beta-catenin and gamma-catenin in the complex and in total cell extracts, as well as a marked reduction in the amount of VE-cadherin present at the cell surface. In contrast, the level of platelet endothelial cell adhesion molecule-1 (PECAM-1), which is located at lateral junctions, was not altered. Supplementation of the cellular antioxidative defences abolished these effects. Finally, the loss of components of the VE-cadherin complex was correlated with increases in vascular permeability and in EC migration. These findings suggest that some of the AGE-induced biological effects on the endothelium could be mediated, at least in part, by the weakening of intercellular contacts caused by decreases in the amount of VE-cadherin present.

Acetylcysteine↗
PubMed2001

Inwardly rectifying K(+) channels in spermatogenic cells: functional expression and implication in sperm capacitation.

To fertilize, mammalian sperm must complete a maturational process called capacitation. It is thought that the membrane potential of sperm hyperpolarizes during capacitation, possibly due to the opening of K(+) channels, but electrophysiological evidence is lacking. In this report, using patch-clamp recordings obtained from isolated mouse spermatogenic cells we document the presence of a novel K(+)-selective inwardly rectifying current. Macroscopic current activated at membrane potentials below the equilibrium potential for K(+) and its magnitude was dependent on the external K(+) concentration. The channels selected K(+) over other monovalent cations. Current was virtually absent when external K(+) was replaced with Na(+) or N-methyl-D-glucamine. Addition of Cs(+) or Ba(2+) (IC(50) of approximately 15 microM) to the external solution effectively blocked K(+) current. Dialyzing the cells with a Mg(2+)-free solution did not affect channel activity. Cytosolic acidification reversibly inhibited the current. We verified that the resting membrane potential of mouse sperm changed from -52 +/- 6 to -66 +/- 9 mV during capacitation in vitro. Notably, application of 0.3-1 mM Ba(2+) during capacitation prevented this hyperpolarization and decreased the subsequent exocytotic response to zona pellucida. A mechanism is proposed whereby opening of inwardly rectifying K(+) channels may produce hyperpolarization under physiological conditions and contribute to the cellular changes that give rise to the capacitated state in mature sperm.

Animals↗
PubMed2001

Adult perineal sarcomas.

BACKGROUND AND OBJECTIVES: Primary perineal sarcoma in adults is a rare disease that has only been documented to occur in isolated case reports. METHODS: To better characterize and define the natural history of perineal sarcoma in adults (> or = 18 years), we reviewed our experience with treatment of perineal sarcoma between 1982 and 1999 (nine cases). RESULTS: Epithelioid sarcoma (n = 4) was the most common histologic subtype. Seven cases (78%) were histologically high grade, and lesions were most commonly < 5 cm. All patients were treated with wide local excision. External beam radiation was the most commonly used form of adjuvant therapy (n = 6). Recurrences were noted in five patients, and the recurrences were most commonly local (60%). Median time to first recurrence was 21 months. Six of nine patients are alive with a median follow-up of 54 months. Three died of recurrent/metastatic disease at 16, 51, and 54 months after initial surgery. CONCLUSIONS: Aggressive therapy and follow-up beginning with wide excision can be associated with long-term survival in adults with primary perineal sarcoma.

Adolescent↗
PubMed2001

Soft tissue sarcomas of the groin: diagnosis, management, and prognosis.

BACKGROUND: Sott tissue sarcomas (STS) of the groin may present a difficult problem because or misdiagnosis as groin hernia and proximity to major neurovascular structures. We evaluated our management and survival in a large cohort of patients. STUDY DESIGN: Patients treated between July 1, 1982 and July 1, 1998 with primary or recurrent STS of the groin were included. Groin sarcomas were defined as those tumors within 5 cm of the inguinal crease. Patient, tumor, clinical, and survival data were analyzed using a log rank test and Cox regression. RESULTS: We treated and followed 88 patients with STS of the groin. The median age was 52 years (range 16 to 86 years) and 55 patients (63%) were male. Disease-specific survival was 72% at 5 years. Tumors tended to be larger than 5 cm (52%), deep (72%), and high-grade (60%). Unfavorable prognostic factors for disease-specific survival were high grade (p < 0.001), neurovascular invasion (p < 0.001), positive margin (p < 0.01), deep depth (p < 0.01), and selection for adjuvant therapy (p < 0.005). Multivariate analysis indicated age greater than 50 years (p < 0.05), high grade (p < 0.001), neurovascular invasion (p < 0.001), and positive microscopic margins (p < 0.001). Fourteen patients (16%) were diagnosed with STS at hernia operation then went on to a definitive operation with no impact on survival. Seventeen patients (19%) had involvement of a major vessel or nerve, and 5 of these ultimately required amputations, 3 for local recurrence. CONCLUSIONS: High grade, neurovascular invasion, and positive microscopic margins are associated with poor outcomes. The biology of these tumors is similar to other extremity STS, and similar principles of management apply. Even with neurovascular involvement, most patients with primary groin STS do not require amputation.

Adolescent↗
PubMed2001

Effects of phycocyanin extract on tumor necrosis factor-alpha and nitrite levels in serum of mice treated with endotoxin.

Phycocyanin is a biliprotein which exerts antioxidative and anti-inflammatory effects in various in vivo and in vitro experimental models. In this study phycocyanin effects on tumor necrosis factor-alpha (TNF alpha) and nitrite levels in serum of mice treated with lipopolysaccharide (LPS) was examined. TNF alpha was measured by cytotoxicity on L-929 cells and nitrite by the Griess reaction, after reduction of all nitrates to nitrites by nitrate reductase, 1 h after LPS injection (0.5 mg/kg i.p.) there was a significant increase in TNF alpha levels in mouse serum. Phycocyanin (50-300 mg/kg p.o.), administered 1 h before LPS, reduced dose-dependently the TNF alpha concentration in serum. After 18 h, LPS (30 mg/kg i.p.) also induced a substantial increase in serum nitrite levels, which were reduced dose-dependently by phycocyanin pretreatment (100-300 mg/kg p.o.). The results indicate that phycocyanin exerts inhibitory effects on TNF alpha and NO production which might be ascribed to the antioxidative properties of the biliprotein.

Animals↗
PubMed2001

"Mangifera indica L. extract (QF808) reduces ischaemia-induced neuronal loss and oxidative damage in the gerbil brain".

The effect of oral administration of Mangifera indica L. extract (QF808) on ischemia-reperfusion-induced neuronal death in the gerbil hippocampal CA1 sector was examined. Oral administration of QF808 for 7 days dose-dependently protected against neuronal cell death following transient ischaemia and reperfusion as assessed by histopathology. In addition, locomotor activity assessment prior to ischaemia and 7 days after correlated well with the histological results. To evaluate redox alterations by reactive oxygen species, total sulfhydryl, non-protein sulfhydryl groups (NPSH), malondialdehyde + 4-hydroxyalkenals and total nitrogen oxide levels were assayed in hippocampus and cortex homogenates. QF808 treatment attenuated NPSH loss, nitrogen oxide levels and lipid peroxidation in the hippocampus. These results suggest that orally administered QF808 is absorbed across the blood-brain barrier and attenuates neuronal death of the hippocampal CA1 area after ischaemia-reperfusion. These protective effects are most likely due to the antioxidant activity of QF808.

Animals↗
PubMed2001

X-ray diffraction and electron microscopy in the polymorphism study of ondansetron hydrochloride.

Using different techniques, we studied the possible formation of ondansetron polymorphs. Ondansetron is a carbazol antiemetic that acts as a competitive, selective inhibitor of 5-HT3 serotonin receptors. The polymorphs were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results suggest that the compounds are not true crystallographic polymorphs, but instead are the product of physical structural changes in the drug, which would be of interest pharmaceutically.

Algorithms↗
PubMed2001

Is decreased HIV-1 infectivity of placental macrophages caused by high levels of beta-chemokines?

The objective of this study was to determine the effect of beta-chemokine secretion on HIV infection of placental macrophages (HF) as compared to monocyte-derived macrophages (MDM). For this purpose, we measured chemokine production in supematants of LPS stimulated and unstimulated HF and MDM. LPS stimulated cultures produced 3 to 10 times higher levels of MIP-1alpha, MIP-1beta and RANTES than unstimulated cultures. The level of MIP-1beta was the highest of the three chemokines secreted upon stimulation of HF cells. Cell cultures were inoculated with HIV-BaL, a R5 virus, and tested for p24 antigen and chemokine production at days 5 and 10 post-infection (P.I.). We did not find significant differences in the level of chemokines produced by HIV-1-infected and uninfected MDM and HF cells. However, significant differences were found in p24 antigen released by unstimulated and LPS stimulated cells. In contrast to HF cells, MDM cultures showed a significant inhibition of p24 antigen production when cells were stimulated with LPS prior to infection. HF cells were less susceptible to HIV-1 infection than MDM, and chemokines produced by HF cells did not result in further inhibition of HIV-1 infection. We found that in contrast to MDM, decreased susceptibility HF cells to HIV infection is not due to increased levels of chemokines, but to decreased HIV-1 coreceptor expression.

CD4 Antigens↗
PubMed2000

Immunohistochemical expression of p53 in breast carcinoma is associated with the intron 1 BglII polymorphism of the p53 gene.

Breast carcinoma is a public health problem worldwide. It is known that both genetic and environmental factors are important for breast carcinogenesis and that structural and/or functional alterations at p53 gene are commonly observed in breast tumors. In addition, polymorphisms of several genes in either their coding or non-coding sequences have been found related to cancer risk and/or clinicopathological characteristics of tumors. In this study we have evaluated the intron 1 BglII polymorphism of the p53 gene with a PCR-based approach in 117 cases of breast cancer and 102 healthy women and its association with the immunohistochemical expression of p53 in the tumors. The results showed that the presence of the polymorphism (allele 2) is highly associated with the tumor expression of p53 (p<0.0001) and that there is a trend for increased frequency of allele 2 in cases than in controls (p=0.2376). These data suggest that the germ-line variation in the intron 1 of the p53 gene could produce functional or structural changes of the protein that is reflected by its abnormal expression.

Bacterial Proteins↗
PubMed2000

Mn2+, Co2+, Cu2+ and Zn2+ complexes with two macrocyclic ligands bearing L-lactate-like functions: potentiometric studies and evaluation of superoxide-scavenging properties of the Mn2+ complex.

Some aerobic organisms devoid of SOD use Mn2+ chelates to scavenge the O2- radical. Since the Mn2+-bis(lactato)diaquo complex is known as having a high SOD-like activity, we prepared manganese(II) complexes with triazamacrocyclic ligands bearing L-lactate-like functions in order to obtain model compounds able to disproportionate the superoxide radical. Thus, two macrocyclic ligands, N,N',N"-tris[2(S)-hydroxybutyric acid]-1,4,7-triazacyclononane, L1, and N,N',N"-tris[2(S)-hydroxybutyric acid]-1,5,9-triazacyclododecane, L2, were prepared and their capacity to retain the Mn2+ ion in aqueous solution was determined from potentiometric experiments. The chelating properties in aqueous solution of each ligand towards Co2+, Cu2+ and Zn2+ ions were also determined. L1 forms complexes with Mn2+, Co2+, Cu2+ and Zn2+ ions with stability constants of 8.33(5), 15.78(5), 17.65(3) and 14.32(1), respectively. L2 forms complexes with Cu2+ and Zn2+ ions with stability constants of 10.67(1) and 6.98(3), respectively. But the constants related to the Mn2+ and Co2+ complexes were too low to be determined by the method used. The stability constants values calculated for L2 complexes are significantly lower than those for the corresponding complexes of L1. Additional spectroscopic measurements were carried out on the Mn2+-L1 system. The electronic spectrum of this system showed a pH-dependence that may be consistent with the formation of hydroxo-species as the ESR spectra recorded at 120 K did not show oxidation of the Mn2+ ion in the pH range studied. The superoxide-scavenging activity of the manganese(II)-L1 complex was investigated using the cytochrome c assay. The Mn2+-L1 system showed an IC50 value of 1.7 microM which indicates that it appears as a potent SOD mimic.

Cations, Divalent↗
PubMed2000

[Estimate of HIV-1 infection prevalence in pregnant women and effectiveness of zidovudine administered during pregnancy in the prevention of vertical transmission].

BACKGROUND: Despite the proven efficacy of zidovudine (ZDV) for reducing perinatal transmission of HIV-1, questions remain about its implementation and effectiveness in routine practice. The aims of this study were to assess the impact of ZDV administered during pregnancy in preventing perinatal HIV-1 transmission, and to determine the proportion of early identification of maternal HIV-1 infection over time. PATIENTS AND METHODS: We prospectively followed from birth a cohort of children born between 1/1/1987 and 31/10/1997 to HIV-1-infected mothers. Infant infection status was assessed by follow-up beyond 18 months or HIV-PCR up to 3 months of age. RESULTS: 229 mothers and 248 infants were identified in the cohort. ZDV was administered during pregnancy as monotherapy to 34 mothers for a mean of 4.7 (3.1) months prior to delivery. There were no differences in baseline characteristics between the treated and untreated groups. Mean (SD) CD4 cell count was 465 (261) cells x 10(6)/l. Factors associated with transmission were a more prolonged time of rupture of obstetric membranes (median 6 vs 1.04 hours; p = 0.023) and ZDV treatment. Among the ZDV-treated mothers only one child was infected (2.9%), whereas 37 children born to 212 untreated women became infected. (OR: 0.14; 95% CI: 0.07-0.92). The estimated prevalence of HIV-1 in pregnant women in our area is about 0.39% (95% CI: 0.34-0.45). From 1987 to 1991, 9.7% of infected women were nor identified at the perinatal period, as compared to 2.5% in the last 5 years of the study period (p = 0.034). CONCLUSIONS: In this study, the estimated prevalence of HIV-1 infection is high. ZDV during pregnancy is significantly associated with a decrease in perinatal transmission in our setting. The awareness of an effective treatment might have contributed to the increased identification of HIV-infected mothers prior to delivery observed over time in our cohort of children born to HIV-infected mothers.

Adolescent↗
PubMed2000

Regulation of endothelial nitric oxide synthase expression by albumin-derived advanced glycosylation end products.

We examined whether albumin-derived advanced glycosylation end products (AGEs) downregulate the expression of endothelial nitric oxide synthase (NOS). Significant reductions in NOS activity and cGMP levels in bovine aortic endothelial cells were observed when exposed to different concentrations of albumin-derived AGEs. Western and Northern blot analyses showed significant decreases at the protein and transcript levels. Both reductions became evident after 24 hours of exposure. Nuclear run-on assays showed that AGE-BSA did not modify the transcription rate of the NOS III gene; however, AGE-BSA treatment markedly reduced the half-life of NOS III mRNA. In addition, AGE-treated endothelial cells displayed significant reduction on their antiplatelet properties. These results indicate that NOS expression is reduced by AGEs by increasing the rate of mRNA degradation and may be relevant to the impairment of some endothelial functions observed in diabetes and aging. The full text of this article is available at http://www.circresaha.org.

Animals↗
PubMed2000

Evaluation of the in vitro antioxidant activity of Mangifera indica L. extract (Vimang).

An extract of Mangifera indica L. (Vimang) was tested in vitro for its antioxidant activity using commonly accepted assays. It showed a powerful scavenger activity of hydroxyl radicals and hypochlorous acid and acted as an iron chelator. The extract also showed a significant inhibitory effect on the peroxidation of rat-brain phospholipid and inhibited DNA damage by bleomycin or copper-phenanthroline systems.

Animals↗
PubMed2000

Normalization of native heart function years after heterotopic transplantation.

We describe a patient whose native heart function has normalized several years after heterotopic heart transplantation. The native heart sustained the patient's circulation at a time when the donor heart was temporarily dysfunctional. Native heart improvement, let alone normalization, is considered rare after heterotopic transplantation but has been noted with increased frequency after long-term unloading with left ventricular assistance.

Cardiomyopathies↗
PubMed2000

Quantitative assessment of apolipoprotein E genotypes by image analysis of PCR-RFLP fragments.

Apolipoprotein E (APOE) genotyping usually involves polymerase chain reaction (PCR) and assessment of restriction fragment length polymorphism (RFLP) by gel electrophoresis. We made determination of HhaI restriction endonuclease digestive patterns more objective and improved diagnostic accuracy with a quantitative approach using sensitive DNA stain (SYBR Green) and image analysis of gel patterns. For distinguishing true and partially-digested restriction fragments, band ratios were calculated for the staining intensity of gel patterns from 116 sample runs of 63 human blood specimens. Each of these specimens was independently genotyped for APOE by at least two (and most of them by three) different PCR-RFLP methods. Based on the distribution of band ratios, decision levels were established and used for developing a program for computer-aided interpretation of APOE genotypes (Microsoft Excel software). Appropriateness of the decision levels for band ratios was validated by APOE genotyping of additional 61 specimens. The approach described here is applicable to a variety of other molecular diagnostic techniques that are based on PCR-RFLP or sequence-specific signal amplifications.

Apolipoproteins E↗