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Biomedical subjects

A García

Publications and source records attributed to A García.

At least 271 records · Page 15Linked to original sources
PubMed1995

Physical association and functional relationship between protein kinase C zeta and the actin cytoskeleton.

Protein kinase C (PKC) was initially identified as a serine/threonine protein kinase dependent on calcium and phospholipids and shown to be involved in intracellular signaling pathways. PKC isoforms have been classified into four groups: Ca(2+)-dependent conventional PKC alpha, beta I, beta II, gamma; Ca(2+)-independent, novel PKC delta, epsilon, eta, phi; atypical PKC zeta, lambda, iota which are not activated by Ca2+ or diacylglycerol, and the recently discovered PKCmu. We reported that activation of the zeta PKC isoform is an important step in interleukin-2 (IL-2)-mediated proliferation (Gómez, J., Pitton, C., García, A., Martínez, A., Silva, A. and Rebollo, A., Exp. Cell Res. 1995. 218: 105.). zeta PKC is also required for mitogenic activation of fibroblasts and for the maturation pathway activated by insulin and Ras. Contradictory results have been reported regarding the subcellular redistribution of zeta PKC upon activation. We report here, using confocal microscopy, that IL-2 induces expression, translocation and association of zeta PKC to a structure coincident with the actin cytoskeleton. Furthermore, we show that zeta PKC has a role in maintaining the integrity of the actin cytoskeletal structure in IL-2-stimulated cells. On the contrary, zeta PKC is not involved in the actin cytoskeleton organization when cells are maintained in IL-4, confirming our previous results showing that IL-4-induced signal transduction is PKC independent.

Actins↗
PubMed1995

Differential effect of rapamycin and cyclosporin A in proliferation in a murine T cell line expressing either intermediate or high affinity receptor for IL-2.

It has been reported that rapamycin (rap), cyclosporin A (CsA) and FK506 have immunosuppressive effect during the activation process of murine T cells. These drugs were investigated for their suppressive effect on a murine T cell line expressing intermediate (TS1 beta) or high (TS1 alpha beta) affinity IL-2R. Rap and CsA strongly inhibit the IL-2-dependent proliferation of TS1 alpha beta cells while they minimally affect the IL-2-mediated proliferation of TS1 beta cells. FK506 does not have any effect on the IL-2-driven proliferation of either TS1 beta or TS1 alpha beta cells. Simultaneous addition of Rap and CsA or Rap and FK506 inhibit the IL-2-mediated proliferation of TS1 beta and TS1 alpha beta cells and therefore FK506 does not revert the inhibition mediated by Rap in TS1 alpha beta cells. Neither Rap nor CsA affect IL-2R expression and internalization in TS1 alpha beta cells. CsA and Rap strongly inhibit the appearance of DNA binding activity of NF-AT and to a lesser extent NF-kappa B. Rap inhibits IL-2-stimulated phosphatidylinositol 3 (PI3) kinase activity in TS1 alpha beta cells. In TS1 beta cells, Rap activates PI3 kinase on its own, inhibiting the IL-2-stimulated PI3 kinase to a lesser extent. These results suggest that PI3 kinase is a target for Rap action. Our results strongly suggest that we have Rap and CsA sensitive and resistant activation pathways operating in TS1 beta and TS1 alpha beta cells.

Base Sequence↗
PubMed1995

The zeta isoform of protein kinase C controls interleukin-2-mediated proliferation in a murine T cell line: evidence for an additional role of protein kinase C epsilon and beta.

In order to address a role of protein kinase C in signal transduction through interleukin-2, interleukin-4, and interleukin-9 receptors, we took advantage of the availability of a selective protein kinase C inhibitor, GF109203X, and the availability of TS1 beta and TS1 alpha beta cell lines which can be maintained in interleukin-2, interleukin-4, or interleukin-9 independently. In this report we report that inhibition of protein kinase C activity by GF109203X does not block interleukin-4- or interleukin-9-dependent proliferation and, on the contrary, does block interleukin-2-dependent proliferation, suggesting that interleukin-4 and interleukin-9 do not use signal transduction pathways mediated by protein kinase C and that the common gamma chain of interleukin-2, interleukin-4, and interleukin-9 receptors is not responsible per se for the activation of protein kinase C through interleukin-2 receptor. Moreover, GF109203X induces apoptosis in cells cultured in interleukin-2 but not in interleukin-4 or interleukin-9. Using antisense oligonucleotides, we report that the zeta and epsilon protein kinase C isoforms are involved in signaling through high-affinity interleukin-2 receptor and beta and zeta are involved in signaling through intermediate-affinity interleukin-2 receptor. Taken together, our data indicate that activation of the zeta, beta, and epsilon protein kinase C isoforms is an important step in interleukin-2-mediated proliferation.

Animals↗
PubMed1995

Comparison of three commercially available monoclonal antibodies directed against pp65 antigen for cytomegalovirus antigenemia assay.

A total of 102 blood samples were used in a prospective parallel and blind study to evaluate three commercially available anti-pp65 monoclonal antibodies for cytomegalovirus antigenemia assay, at the dilutions recommended by their manufacturers. Cytomegalovirus was detected in 42 samples (41.2%), by either culture (32 samples; 76.2% of positive samples) or antigenemia (38 samples; 90.6%). Of the antigenemia-positive samples, 37 were detected by Monofluo kit CMV, which showed statistically significant differences when compared with the other reagents (Biosoft 1C3 and Clonab C10/C11), in either positivity rates (P < 0.004) or positive cell counts (P < 0.001). This reagent also gave better results in fluorescence quality than 1C3 and C10/C11. However, technical differences were not reflected in the clinical relevance of the antigenemia results.

Antibodies, Monoclonal↗
PubMed1995

Dexamethasone up-regulates a constitutive nitric oxide synthase in cerebellar astrocytes but not in granule cells in culture.

Treatment of rat cerebellar astrocyte-enriched primary cultures with dexamethasone enhances the nitric oxide-dependent cyclic GMP formation induced by noradrenaline in a time-(> 6 h) and concentration-dependent manner (half-maximal effect at 1 nM). Stimulation of cyclic GMP formation by the calcium ionophore A23187 is similarly enhanced. In contrast, cyclic GMP accumulation in cells treated with lipopolysaccharide is inhibited by dexamethasone. The potentiating effect of dexamethasone is prevented by the protein synthesis inhibitor cycloheximide and is not due to increased soluble guanylate cyclase activity. Agonist stimulation of [3H]arginine to [3H]citrulline conversion is enhanced by dexamethasone in astrocytes but not in cerebellar granule cells. These results indicate that glucocorticoids may up-regulate astroglial calcium-dependent nitric oxide synthase while preventing expression of inducible nitric oxide synthase and are the first report of a differential long-term regulation of the expression of neuronal and astroglial constitutive nitric oxide synthase activities.

Amino Acid Oxidoreductases↗
PubMed1995

Treatment with various antibiotics of experimental endocarditis caused by penicillin-resistant Streptococcus sanguis.

BACKGROUND: Streptococcus sanguis currently accounts for one-half of viridans streptococci. Treatment has become complicated due to the increase in resistance to penicillin and cephalosporins. The aim of the study was to assess the efficacy of various antibiotics as monotherapy and in association with gentamicin, in a experimental model of infective endocarditis in rabbits. The effects were compared with a control group and a group given classical penicillin-gentamicin treatment. MATERIAL AND METHODS: Infective endocarditis was induced in 180 rabbits with a clinical isolate of Streptococcus sanguis. Treatment was started 48 h after infection, and lasted 5 days. The animals were divided into nine groups of 20 rabbits: G1, untreated controls; G2, penicillin-gentamicin; G3, clindamycin-gentamicin; G4, imipenem; G5, imipenem-gentamicin; G6, teicoplanin; G7, teicoplanin-gentamicin; G8, vancomycin and G9, vancomycin-gentamicin. Response to therapy was evaluated by mortality curves, as negative blood cultures, concentration of S. sanguis in aortic vegetations and rate of sterilization of vegetations. RESULTS: Vegetation weight was significantly lower in treated groups than in controls; lower weights were found in G5, 6, and 9. G9 sterilized 75% of the vegetations. Death occurred in 25% of the control group and in 4.76% of G6 and 7. Blood cultures became negative most rapidly in G9. CONCLUSIONS: Combined treatment with vancomycin-gentamicin may be highly efficacious in patients with endocarditis caused by penicillin-resistant Streptococcus sanguis. Other combinations, such as imipenem-gentamicin and teicoplanin-gentamicin, may be also advantageous.

Animals↗
PubMed1995

Abnormal polymerization and normal binding of plasminogen and t-PA in three new dysfibrinogenaemias: Barcelona III and IV (gamma Arg 275-->His) and Villajoyosa (gamma Arg 275-->Cys).

Congenital dysfibrinogenaemia was found in three non-related patients. None of them had a haemorrhagic tendency, but one gave a thrombotic history. When their fibrinogens were treated with thrombin, they released fibrinopeptides A and B at normal rates, but the resultant fibrin monomers produced exhibited abnormal polymerization curves. This abnormality was more marked in fibrinogen Villajoyosa than in Barcelonas III and IV. Plasminogen and t-PA binding to fibrin monomers from the three dysfibrinogenaemias was similar to that of normal fibrin monomers. The gamma chain was purified from the three fibrinogens, treated with CNBr and the peptides produced were separated by reversed-phase HPLC. Chromatograms of digested fibrinogens showed an abnormal peak that was not present in the normal gamma chain. Amino acid sequence analysis of abnormal peptides and genomic DNA sequencing revealed that the gamma arginine 275 had been changed in the three fibrinogens; in two cases it was substituted by histidine, and in the third by cysteine. The altered properties observed in fibrin monomers produced from fibrinogen with the gamma Arg 275-->His or gamma Arg 275-->Cys substitution, suggests that this amino acid is important in maintaining the protein structure necessary for normal polymerization, but is not essential for the binding of t-PA or plasminogen to fibrin. It also suggests that the change Arg-->Cys produces more severe alterations in the functions of fibrinogen than the substitution Arg-->His.

Adult↗
PubMed1995

Information as a fundamental attribute among outpatients attending the nuclear medicine service of a university hospital.

The aim of this study was to assess outpatients' satisfaction with the service received in the nuclear medicine service of the Hospital Clinic i Provincial of Barcelona in February 1993. The patients were randomly assigned to one of two groups: group 1 received information about their diagnostic procedure, whereas group 2 did not (a control group). A questionnaire was used to assess patients' degree of satisfaction. The questionnaire was administered to 803 patients, 243 (30.26%) of whom completed it and returned it. The following factors were significantly related to high scores on the satisfaction scale: age (P < 0.015), waiting time (P < 0.001), treatment by assisting personnel (P < 0.001), treatment by personnel at the service reception (P < 0.01), waiting room habitability (P < 0.01), communication variables (P < 0.03) and low scores on the anxiety scale (P < 0.02). Group 1 perceived more positively treatment by personnel at reception (P < 0.041), treatment by assisting personnel (P < 0.027), waiting room habitability (P < 0.035) and communication variables (P < 0.001). The anxiety scale scores among this group were significantly lower. We conclude that when information is supplied to patients, their anxiety decreases before a diagnostic procedure, which significantly improves their perception of the factors that generate satisfaction among patients.

Adolescent↗
PubMed1995

Comparison of several fixation methods for cytomegalovirus antigenemia assay.

Two fixation methods based on formaldehyde or acetone for qualitative cytomegalovirus antigenemia assay were evaluated on 405 consecutive blood samples. Cytomegalovirus was detected in 40 samples by the antigenemia assay: 36 were detected by formaldehyde fixation; 22, by acetone; and 18, by both methods. Differences were statistically significant (P = 0.0043). In addition, four fixation methods (two based on formalin [with and without permeabilization] and two using acetone at different fixation times) for quantitative antigenemia assay in a different set of 32 samples from known viremic patients were evaluated. Formalin-based methods were superior to acetone-based methods, showing statistically significant differences in either the number of positive samples detected (P < 0.02; McNemar test) or the mean positive cell counts (P < 0.003; two-tailed Student's t test for paired samples). No differences between the two formalin-based methods were found. We recommend the formaldehyde fixation procedure without subsequent permeabilization because of its simplicity and sensitivity.

Acetone↗
PubMed1995

Crohn's disease presented by episiotomy dehiscence and perineal fistula.

A case of Crohn's disease is described which was first manifested by episiotomy dehiscence and perineal fistula after an instrumental delivery. The female newborn showed a congenital rectovaginal fistula and hexadactylia. Differential diagnosis and possible relationship between both fistulas are discussed.

Abscess↗