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Biomedical subjects

G Espinosa

Publications and source records attributed to G Espinosa.

At least 73 records · Page 4Linked to original sources
PubMed1993

Effect of endothelin-1 on neutrophil adhesion to endothelial cells and perfused heart.

BACKGROUND: Based on recent evidence showing that endothelin-1 stimulates several activation mechanisms on neutrophils, the aim of the present study was to analyze the effects of endothelin-1 on neutrophil adhesion to endothelial cells and neutrophil accumulation in the heart. METHODS AND RESULTS: The experiments included (1) adhesion of 51Cr-labeled human neutrophils to bovine endothelial cells in culture both in the presence and absence of monoclonal antibodies against the alpha- and beta-subunits of integrins; (2) surface expression of the alpha- and beta-integrin antigens; (3) accumulation of 51Cr-labeled neutrophils on the isolated perfused rabbit heart; (4) in vivo accumulation of autologous neutrophils in the heart, as assessed by myeloperoxidase activity. Endothelin-1 stimulated neutrophil adhesion to endothelial cells (increase of 1 x 10(5) +/- 1 x 10(4) neutrophils per well). The endothelin-1-induced adhesion was blocked (83 +/- 6%) by the anti-CD18 antibody TS1/18 and by several anti-alpha-subunit antibodies. The expression of CD18 and CD11b on the neutrophil surface was also increased by endothelin-1. Endothelin-1 enhanced neutrophil accumulation in the isolated rabbit heart by 4.2 times throughout a TS1/18-inhibitable mechanism. Myeloperoxidase activity increased by 4.2 times in hearts infused in vivo with endothelin-1. CONCLUSIONS: Endothelin-1 stimulates neutrophil adhesion to endothelial cells by an effect on the expression of adhesive molecules on the neutrophil surface. Endothelin-1 stimulates neutrophil accumulation in vivo and in vitro in the heart. Antibodies against the integrin complex block the endothelin-1-dependent neutrophil adhesion. These findings have potential importance in the pathophysiology of endothelin-1-increased states.

Animals↗
PubMed1992

Synchronous cecal and sigmoid volvulus. Report of a case.

Volvulus is a rare cause of intestinal obstruction in the U.S. Sigmoid colon volvulus is the most frequent, followed by cecal volvulus. The simultaneous occurrence of cecal and sigmoid colon volvulus is extremely unusual. We are reporting what to our knowledge is the third case.

Cecal Diseases↗
PubMed1992

Isolation and identification of xochitloldione and isoxochitlolone from Cnidosculus urens.

Major components of MeOH extracts from the plant roots of Cnidosculus urens purified by cc and tlc and crystallization were lupeol acetate and the previously unreported compounds isoxochitlolone [1] and xochitloldione [2], which were identified through mass, ir, nmr, and uv spectroscopy and X-ray crystallography. In preliminary testing, isoxochitlolone has been found to be active against Escherichia coli and Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed1992

Renal and systemic effects of aminoacids administered separately: comparison between L-arginine and non-nitric oxide donor aminoacids.

The present study examined the mechanisms of the renal effect of the NO-donor aminoacid, L-Arg and different non-NO-donor aminoacids, namely L-Asn, L-Ala, L-Gly L-Gln administered separately. In conscious, unrestricted Wistar rats, a bolus of L-Arg produced a short-lasting decrease in mean arterial pressure. No variations in mean arterial pressure were found with either L-Gly, L-Asn, L-Ala or L-Gln. This effect of L-Arg was inhibited by NwNLA, methylene blue and atropine and not affected by meclofenamate. Simultaneously, a dose-response diuretic and natriuretic effect was observed with all the aminoacids. In further experiments with L-Arg and L-Gly, this effect was associated with increased glomerular filtration rate, renal plasma flow, fractional sodium and free water excretion and urinary cyclic guanosine monophosphate. These effects of L-Arg and L-Gly were inhibited by NwNLA. On the contrary, no inhibition by NwNLA was detected on the diuretic, natriuretic and renal hemodynamic effects of L-Gln, and the diuretic and natriuretic effects of L-Asn or L-Ala. Our results show that all the assayed aminoacids were endowed of diuretic and natriuretic capabilities. Such effects were apparently related with a NO-mediated mechanism in the case of L-Arg and L-Gly, but not in the case of L-Gln, L-Asn or L-Ala, therefore suggesting that more than one mechanism is involved in the renal effect of the different aminoacids. Simultaneously, only L-Arg produced a NO-, cyclic guanosine monophosphate-dependent hypotensive effect, which was not shared by the other assayed aminoacids.

Amino Acids↗
PubMed1990

Isoelectric focusing in immobilized pH gradients of phosphoglucomutase and esterases from the spiny lobster.

A method is described for detecting polymorphisms of cephalothorax and tail homogenates of 25 puerulus staged Panulirus argus in phosphoglucomutase (PGM) and esterases. Isoelectric focusing in immobilized pH gradients was used. In the pH 6.0-8.0 interval for phosphoglucomutase and in the pH 3.5-5.0 and 4.2-4.9 ranges for esterases, both enzymes appeared as polymorphic band patterns. These could be explained by one locus with 2 alleles for phosphoglucomutase and 3 loci with 2, 3 and 4 alleles for esterases. Esterases exhibit a more extensive polymorphism in immobilized pH gradients than in polyacrylamide gel electrophoresis.

Alleles↗
PubMed1990

Sexual behavior of Filipino female prostitutes after diagnosis of HIV infection.

A study of female prostitutes in Manila who tested positive for human immunodeficiency virus (HIV) antibody ascertained demographic and sexual behavior information following diagnosis. Counselling alone did not appear to have a major impact on the sexual behavior of the HIV positive women since most continued to work as prostitutes. Switching from high risk to low risk jobs in bars is not effective in preventing HIV positive women from engaging in prostitution. Revoking work permits is only effective if enforced with adequate follow up. Alternative job training programs may offer a viable approach.

Contraceptive Devices, Male↗
PubMedDate not supplied

A fuzzy ARTMAP based on quantitative structure-property relationships (QSPRs) for predicting aqueous solubility of organic compounds.

Quantitative structure-property relationships (QSPRs) for estimating aqueous solubility of organic compounds at 25 degrees C were developed based on a fuzzy ARTMAP and a back-propagation neural networks using a heterogeneous set of 515 organic compounds. A set of molecular descriptors, developed from PM3 semiempirical MO-theory and topological descriptors (first-, second-, third-, and fourth-order molecular connectivity indices), were used as input parameters to the neural networks. Quantum chemical input descriptors included average polarizability, dipole moment, resonance energy, exchange energy, electron-nuclear attraction energy, and nuclear-nuclear (core-core) repulsion energy. The fuzzy ARTMAP/QSPR correlated aqueous solubility (S, mol/L) for a range of -11.62 to 4.31 logS with average absolute errors of 0.02 and 0.14 logS units for the overall and validation data sets, respectively. The optimal 11-13-1 back-propagation/QSPR model was less accurate, for the same solubility range, and exhibited larger average absolute errors of 0.29 and 0.28 logS units for the overall and validation sets, respectively. The fuzzy ARTMAP-based QSPR approach was shown to be superior to other back-propagation and multiple linear regression/QSPR models for aqueous solubility of organic compounds.

Journal Article↗
PubMedDate not supplied

An integrated SOM-fuzzy ARTMAP neural system for the evaluation of toxicity.

Self-organized maps (SOM) have been applied to analyze the similarities of chemical compounds and to select from a given pool of descriptors the smallest and more relevant subset needed to build robust QSAR models based on fuzzy ARTMAP. First, the category maps for each molecular descriptor and for the target activity variable were created with SOM and then classified on the basis of topology and nonlinear distribution. The best subset of descriptors was obtained by choosing from each cluster the index with the highest correlation with the target variable and then in order of decreasing correlation. This process was terminated when a dissimilarity measure increased, indicating that the inclusion of more molecular indices would not add supplementary information. The optimal subset of descriptors was used as input to a fuzzy ARTMAP architecture modified to effect predictive capabilities. The performance of the integrated SOM-fuzzy ARTMAP approach was evaluated with the prediction of the acute toxicity LC50 of a homogeneous set of 69 benzene derivatives in the fathead minnow and the oral rat toxicity LD50 of a heterogeneous set of 155 organic compounds. The proposed methodology minimized the problem of misclassification of similar compounds and significantly enhanced the predictive capabilities of a properly trained fuzzy ARTMAP network.

Fuzzy Logic↗
PubMedDate not supplied

Behçet's disease and hereditary periodic fever syndromes: casual association or causal relationship?

OBJECTIVE: Mutations in the MEFV and the type 1 TNF receptor (TNFRSF 1A) genes have recently been linked to familial Mediterranean fever (FMF) and TNF receptor-associated periodic syndrome (TRAPS), respectively. A higher prevalence of Behçet's disease (BD) among FMF patients has been described compared to the general population. The aim of this study was to evaluate whether FMF TRAPS and BD could be genetically related. METHODS: We screened a cohort of 50 BD patients and 100 healthy subjects for the common MEFV and TNFRSF 1A mutations. An initial screening of exons 10 and 2 of the MEFV gene and exon 4 of the TNFRSF 1A was performed in all chromosomes. RESULTS: The heterozygous MEFV mutation (K695R) was found in one (2%) BD patient. Analysis for FMF mutations in the control group revealed that 5 (5%) individuals bore MEFV gene mutations (3 were heterozygous for the E148Q and 2 were heterozygous for the A744S). At codon 202, there were no differences in allele frequencies between BD and control population: 73%R 27%Q in the BD patients vs 75%R 25%Q in controls. Concerning mutations in the TNFRSF 1A gene, the R92Q mutation was present in heterozygous state in one (2%) BD patient and in 4 (4%) controls without differences between allele frequencies: 99%R 1%Q in BD patients vs 98%R 2%Q in controls, respectively. There was no association between the clinical manifestations of BD patients and the presence of a particular polymorphism or a mutation. CONCLUSIONS: Neither FMF nor TRAPS are genetically associated with BD in our cohort of Spanish patients.

Behcet Syndrome↗
PubMedDate not supplied

Isotype distribution and clinical significance of antibodies to cardiolipin, phosphatidic acid, phosphatidylinositol and phosphatidylserine in systemic lupus erythematosus: prospective analysis of a series of 92 patients.

OBJECTIVE: To determine the prevalence and correlation with clinical manifestations of the IgG and IgM isotypes of antibodies to cardiolipin (aCL), phosphatidic acid (aPA), phosphatidylinositol (aPI) and phosphatidylserine (aPS) in patients with systemic lupus erythematosus (SLE). METHODS: Clinical and laboratory features of 92 consecutive unselected patients with SLE were prospectively studied over two years. aCL, aPA, aPI and aPS were determined by ELISA. RESULTS: aCL were detected in 34 (37%) patients, aPA in 26 (28%), aPI in 22 (24%), and aPS in 29 (32%). A significant association was found between the appearance of thrombosis and the presence of IgG aCL (p < 0.001) and IgG aPS (p < 0.05). A significant association was also found between thrombocytopenia and the presence of IgG aCL (p < 0.001), IgG aPA (p < 0.01), IgG aPI (p < 0.05), and IgG aPS (p < 0.001). The development of hemolytic anemia was associated with the detection of IgM aCL (p < 0.001), IgM aPA (p < 0.05), IgM aPI (p < 0.001), and IgM aPS (p < 0.01). CONCLUSION: We found a relatively high prevalence of aCL, aPA, aPI and aPS in our SLE population and confirmed the presence of a correlation between the IgG isotype of these antibodies and thrombosis and thrombocytopenia, and also between the IgM isotype and hemolytic anemia. These results demonstrate the variety of antiphospholipid antibodies that can be detected in SLE patients, as well as their association with the clinical manifestations of the antiphospholipid syndrome.

Adolescent↗