Recombinant streptokinase for the treatment of thrombotic disorders.
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Adult↗
Biomedical subjects
E Muñoz
Publications and source records attributed to E Muñoz.
Study of a Fenton type reaction: effect of captopril and chelating reagents.
The purpose of this study was to determine if captopril, an angiotensin-converting enzyme inhibitor, could interact with iron ions and so modify a Fenton type reaction. Results indicate that different degrees of thiobarbituric acid-reactive substance from deoxyribose are obtained in an ascorbate-driven Fenton system depending on the order of addition of captopril and iron to the incubation medium. Similar results were obtained with the chelating reagents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, indicating that the buffer solution plays a relevant role when a particular iron complex is formed with a chelating agent. These metal complexes produce oxidizing species in a Fenton type system whose nature is discussed.
Captopril↗
Selective decrease of CD26 expression in T cells from HIV-1-infected individuals.
The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.
Acquired Immunodeficiency Syndrome↗
Interleukin-1 induces protein tyrosine phosphorylation in T cells.
Interleukin (IL)-1 alpha activates multiple signal transmission pathways in the T helper type 2 cell line, D10A, and these pathways are linked to two separate IL-1 receptors (IL-1R). In the present report we show that IL-1 induces the activation of tyrosine kinase in these cells, leading to tyrosine phosphorylation of a subset of proteins of 38, 75, 97 and 115 kDa. This type of phosphorylation is prevented by a monoclonal antibody directed against the 80-kDa IL-1R and by tyrphostins which are specific inhibitors of tyrosine kinases. In addition, this inhibitor blocks IL-1-and IL-2-induced proliferation in D10A cells as well as the c-myc and c-myb proto-oncogene mRNA expression in response to IL-1. Interestingly, the inhibitor of cAMP-dependent kinase, H-8, only blocks IL-1-induced c-myb, but not c-myc mRNA expression. Altogether, our results demonstrate that the activation of a tyrosine kinase(s) is an early and major event that happens after IL-1/IL-1R interaction, leading to an increase in intracellular cAMP which results in c-myb and IL-5 mRNA expression. Independent of cAMP, by tyrosine phosphorylation of specific substrates IL-1 also induces c-myc and IL-6 mRNA expression and cellular proliferation.
Animals↗
Interleukin-1 induces c-fos and c-jun gene expression in T helper type II cells through different signal transmission pathways.
Interleukin (IL)-1 induces proliferation and expression of several protooncogenes in the T helper 2 cell line D10A. We have analyzed the signal transmission pathways activated by IL-1 in these cells, leading to the expression of c-jun and c-fos. IL-1 induced c-jun gene transcription and mRNA expression by means of a pathway dependent on protein tyrosine kinase activity since tyrphostin, a specific inhibitor of tyrosine kinase, inhibited this induction. This mechanism of transmission signaling was independent of protein kinase C (PKC) and was linked to the 80-kDa IL-1 receptor (IL-1R). In addition, phorbol esters did not induce c-jun mRNA expression, whereas c-fos mRNA expression mediated by IL-1 dependent on PKC; this pathway was linked to a different, still unidentified IL-1R that was functional in the D10A cell line. Accumulation of intracellular cAMP generated by IL-1 through the 80-kDa IL-1R negatively regulated c-fos expression which was induced by IL-1 through PKC activation. We conclude that IL-1 modulates the expression of c-fos in D10A cells by occupying of two independent IL-1R that are linked to different signal transduction pathways.
Cyclic AMP↗
Statistical evaluation of the predictive power of fine needle aspiration (FNA) of salivary glands. Results and cytohistological correlation.
Fine needle aspiration (FNA) of the salivary glands was carried out on 97 patients. Diagnosis was confirmed by histological findings in 93 patients. There were 75 benign lesions (including 52 benign tumours) and 18 malignant lesions. In our series "positive predictive value" of FNA was 0.900 and the negative predictive value was 0.963. Thus, the probability of a false positive is 0.100 and of a false negative 0.037.
Biopsy, Needle↗
Comparative study of in situ hybridization and immunohistochemical techniques for the detection of human papillomavirus in lesions of the uterine cervix.
Among the techniques currently used for the detection of human papillomavirus (HPV) in genital lesions, only two correlate HPV with the histopathological findings of the lesion: immunohistochemistry and in situ hybridization. Consequently, we were prompted to carry out a comparative study on both techniques to check their utility and efficacy as routine diagnostic methods. 52 biopsy specimens of uterine cervix diagnosed histopathologically as condylomas and cervical intraepithelial neoplasia+koilocytosis were studied by immunohistochemical and in situ hybridization techniques using a polyclonal antibody against the common antigen of the HPV capsid and three biotinylated DNA probes specific to HPV types 6/11, 16/18 and 31/35/51. Immunohistochemistry detected 21 positive cases (40.38%), whereas in situ hybridization detected 40 positive cases (76.92%); of the latter, 30 were positive for HPV types 6/11, 3 for HPV types 16/18 and 11 for HPV types 31/35/51. The results suggest that in situ hybridization is a more sensitive technique than immunohistochemistry. However, we recommend the use of both techniques in the case of potentially malignant lesions since better prognostic information can be obtained from joint analysis of both results.
Adolescent↗
CD26 induces T-cell proliferation by tyrosine protein phosphorylation.
CD26 antigen distribution among lymphoid cells and its participation in the process of lymphocyte activation and proliferation has been widely documented. However, the molecular and biochemical mechanisms coupled to the CD26 molecule are not yet known. With different monoclonal antibodies (mAb) we have detected that approximately 56% of CD4+ and 35% of CD8+ cells from peripheral blood lymphocytes express CD26 and the expression of this antigen is required for antigen- but not for mitogen-induced proliferation unless exogenous interleukin-2 (IL-2) is added to the culture. The stimulation of nylon wool-separated T cells and T-cell clones by the anti-CD26 mAb, 134-2C2, induced tyrosine phosphorylation on a subset of proteins of 50,000, 46,000, 26,000, 24,000 and 21,000 MW. This pattern of phosphorylation was not affected by the presence of 12-myristate 13-acetate (PMA), although this cofactor is required for CD26-mediated IL-2 mRNA expression and T-cell proliferation. When a specific tyrosine kinase inhibitor, Tyrphostin, was used in CD4+ cells cultures stimulated with 134-2C2 and PMA, the proliferation and the expression of IL-2 mRNA were inhibited. Thus, protein tyrosine phosphorylation seems to play a major role in CD26-mediated T-cell proliferation.
Adult↗
Study of infection by human papillomavirus in severe dysplasias and carcinomas in situ of the uterine cervix using immunohistochemistry and in situ hybridization.
Diagnosis of human papillomavirus (HPV) infection in uterine cervical lesions is usually based on histopathological criteria and, in some cases, is confirmed by immunohistochemistry. The recent development of in situ hybridization techniques has facilitated the detection of HPV in these lesions. Consequently, we carried out a study on 18 uterine cervical biopsy specimens histopathologically diagnosed as severe dysplasias and carcinomas in situ, using an immunohistochemical method with a rabbit polyclonal antibody against the HPV common structural antigen and in situ hybridization techniques with three biotinylated DNA probes for HPV types 6/11, 16/18, and 31/35/51. By immunohistochemistry only one case (5.5%) proved to be positive, whereas by in situ hybridization 12 HPV-positive cases were obtained (66.6%), of which 7 were positive for HPV types 16/18 (38.8%) and 6 for HPV types 31/35/51 (33.3%). One case was positive with positive with both DNA probes. From our results it can be inferred that in situ hybridization is a more sensitive technique than immunohistochemistry for confirming the presence of HPV in severe dysplasias and carcinomas in situ of the uterine cervix. Furthermore, in situ hybridization provides much more information than immunohistochemistry since it permits the identification of the HPV types causing the lesion.
DNA Probes↗
[Primary leiomyosarcoma of the gallbladder].
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Aged↗
Purification of streptokinase by affinity chromatography on immobilized acylated human plasminogen.
Streptokinase is an extracellular protein produced by several strains of streptococci. It functions in the species-specific conversion of plasminogen to plasmin. In this paper we describe the purification of streptokinase by affinity chromatography on human plasminogen acylated with p'-nitrophenyl p-guanidinobenzoate. The acylated and non-acylated plasminogen and plasmin were coupled to cyanogen bromide-activated Sepharose 4B and evaluated for streptokinase purification. These results show that a homogeneous preparation of streptokinase with high specific activity and high yield can be obtained using acylated plasminogen. This method permits the binding of one milligram of streptokinase per milliliter of swollen gel.
Acylation↗
Modifications of "A cells" in the development of experimentally induced pancreatic ductal adenocarcinoma: an ultrastructural and immunohistochemical study.
In the hamster-BOP model, modifications occur in the endocrine portion of the pancreas during the induction of well-differentiated ductal carcinomas. In the present work, using immunohistochemical techniques it was possible to observe that the A cells in preserved islets and in the initial phase of the carcinogenic process were localized in the peripheral part of the islets. In animals with tumours, A cells were found to form part of the tumour glands and/or the tumoral stroma; this localization was seen to depend on the developmental phase of the tumour. A focal dispersion of A cells was observed in the animals with ductal carcinoma.
Adenocarcinoma↗
Captopril does not scavenge superoxide: captopril prevents O2-. production by chelating copper.
The purpose of this study was to use a direct method, that of electron spin resonance spectroscopy, to evaluate the ability of captopril, an angiotensin-converting enzyme inhibitor, to prevent the superoxide-mediated formation of phenyl radicals. Results indicate that, under certain conditions, captopril is a potent inhibitor of the generation of phenyl radicals, produced by the autoxidation of phenylhydrazine. The inhibitory effect of captopril, however, was better understood as a direct interaction of the drug with the metals that catalyze the autoxidation process rather than as a reaction of captopril with the free radicals generated. This last conclusion was supported by the finding that captopril was not able to inhibit the superoxide anion-mediated reduction of nitroblue tetrazolium.
Captopril↗
Production of IL-1 alpha by activated Th type 2 cells. Its role as an autocrine growth factor.
Autocrine growth of Th type 2 cells has been reported to be mediated by the lymphokine IL-4. In this report we present evidence that in addition to IL-4 Th2 cells also produce IL-1 alpha in its active form in the absence of APC. We have found that this cytokine is an autocrine growth factor, because proliferation of Th2 cells in response to several stimuli is inhibited by anti-IL-1 alpha or anti-IL-1R mAb, or by an IL-1 alpha antisense oligodeoxynucleotide. However, Th1 cells do not produce this cytokine. We have investigated the role of endogenous IL-1 alpha on the induction of c-myc and c-myb, two protooncogenes involved in T cell activation. Here we show that endogenous IL-1 alpha is involved in the activation of both protooncogenes. Our results suggest that a possible function of IL-1 alpha, and perhaps other growth factors, might be to sustain or amplify the initial second messengers derived through the TCR. The possible implications of this finding with respect to interactions between T cell subsets and B cells or macrophages are discussed.
Antibodies, Monoclonal↗
Superinduction of IL-2 gene transcription in the presence of cycloheximide.
Lymphokine production is regulated both at the transcriptional and the posttranscriptional level. To date, it has been shown that the protein synthesis inhibitor cycloheximide (CHX) up-regulates IL-2 expression in T cells by stabilizing its mRNA. In this report we have examined the effect of CHX on IL-2 at the transcriptional level. We have found that CHX has a positive regulatory function in IL-2 transcription, which is dependent on prior activation of this gene. This is not due to posttranslational conversion of inactive NFkB into its active form by CHX, because a clustered mutation in the kB-like sequence in the IL-2 enhancer that abrogates NFkB binding does not affect the up-regulation of IL-2 transcription. These results favor the hypothesis that, in addition to positive factors, negative elements regulate IL-2 transcription. Furthermore, we have tested the effect of CHX on IL-4 and granulocyte-macrophage-CSF transcription of both lymphokines. These results suggest that transcriptional up-regulation by CHX may be specific for IL-2 with respect to lymphokine expression.
Cells, Cultured↗
Tyrosine protein phosphorylation is required for protein kinase C-mediated proliferation in T cells.
We have studied the role of tyrosine kinase in PMA-stimulated T cells. Protein kinase C (PKC)-mediated D10A cell proliferation is inhibited by the specific inhibitor of tyrosine kinase, tyrphostin. This inhibitor selectively blocks the mRNA expression of the proto-oncogene c-myc in response to the phorbol ester, PMA. On the other hand, the same doses of this inhibitor do not affect the mRNA expression of the proto-oncogene c-fos in PMA-stimulated D10A cells. Phorbol esters induce in this T cell line the tyrosine phosphorylation of a unique protein of 42 kDa and the enzyme PKC is required for this activity.
Blotting, Northern↗
Health status among Hispanics: major themes and new priorities.
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Cuba↗
IL-1 signal transduction pathways. I. Two functional IL-1 receptors are expressed in T cells.
We have recently characterized a subline of the Th2 cell line D10.G4.1, D10A, which responds to exogenous IL-1 in the absence of cofactors. In this cell line IL-1 activates two distinct transmission signal pathways, one leading to increased levels of intracellular cAMP, and the other to the phosphorylation of an 80-kDa substrate of protein kinase C (PKC). To determine whether both pathways are activated upon occupancy of a single IL-1R, we used a mAb, M15, which blocks binding of IL-1 to the 80-kDa IL-1R, known to be expressed in Th2 cells. Whereas M15 was able to inhibit the accumulation of cAMP induced by IL-1, it had no effect on the IL-1-induced phosphorylation of the 80-kDa substrate of PKC or the c-fos mRNA expression. In addition, we show that IL-1 induces the expression of the two proto-oncogenes c-myb and c-myc through the 80-kDa IL-1R, and that this induction is PKC independent. The proliferation of D10A cells in response to IL-1 is blocked by M15, but is unaffected by H-7, a potent inhibitor of PKC. These results indicate that the IL-1-induced proliferation of D10A cells is independent of PKC. In addition, IL-1 induces c-fos mRNA expression in thymocytes but not in EL-4 cells.
Animals↗