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Biomedical subjects

A Prieto

Publications and source records attributed to A Prieto.

At least 91 records · Page 5Linked to original sources
PubMed1995

Persistent lymphocytosis of natural killer cells in autoimmune thrombocytopenic purpura (ATP) patients after splenectomy.

We report three patients with primary autoimmune thrombocytopenic purpura (ATP) who developed an absolute lymphocytosis (lymphocyte count > 5 x 10(9)/l) after splenectomy and with a lymphocyte count between 5.4 and 8.9 x 10(9)/l. An immunophenotype study showed that the peripheral blood lymphocytosis was a persistent NK cell expansion (CD2+, CD56+, CD3-), and was characterized by a typical large granular lymphocytes (LGL) morphology. Two of these three ATP patients were refractory to splenectomy.

Aged↗
PubMed1994

Structural investigation of two cell-wall polysaccharides of Penicillium expansum strains.

The structure of two cell-wall polysaccharides isolated from three different strains of Penicillium expansum, the type species of the genus, have been established by 1D and 2D NMR spectroscopy, and also by methylation analyses. The water-soluble polysaccharide F1S-B consisted of a linear tetrasaccharide repeating unit with the following structure: [-->6)-beta-D-Galf-(1-->5)-beta-D-Galf-(1-->5)-beta-D-Gal f-(1-->5)-beta-D- Galf-(1-->]n The alkali-soluble polysaccharide F1I is a (1-->3)-alpha-D-glucan.

Carbohydrate Conformation↗
PubMed1994

Structural studies of fungal cell-wall polysaccharides from two strains of Talaromyces flavus.

The water-soluble cell-wall polysaccharides isolated from strains CBS 352.72 and 310.38 of Talaromyces flavus have been investigated by chemical analyses and NMR studies. Two different skeletons coexist, having the structures: [formula:see text]. The small differences between the polysaccharides isolated from both strains are probably due to slight diminution of branching in strain 352.72, as compared with strain 310.38.

Carbohydrate Sequence↗
PubMed1994

Intracavitary prophylactic treatment with interferon alpha 2b of patients with superficial bladder cancer is associated with a systemic T-cell activation.

The activation and proliferation of peripheral blood mononuclear cells (PBMNCs) are complex processes involving several surface molecules, cell secretion and response to cytokines. This paper investigates the immunomodulatory effect of prophylactic treatment with interferon alpha 2b (IFN-alpha 2b) upon the blastogenic response of PBMNCs from patients with superficial transitional cell carcinoma (STCC) of the bladder to mitogenic signals that interact with surface molecules [phytohaemagglutinin, PHA and anti-CD3 monoclonal antibodies, (MAbs)]. PBMNCs from the patients were studied prior to the transurethral resection (TUR) of the tumour, during the second month of prophylactic intravesical instillation of IFN-alpha 2b and 3 and 6 months after finishing the instillation treatment. The [3H]thymidine uptake of PBMNCs from 17 patients with STCC of the bladder after 5 days of PHA and anti-CD3 MAb stimulus was found to be significantly lower than that of healthy controls (P < 0.05). The addition of interleukin 2 (IL-2) to the culture medium did not correct this defective proliferative response to PHA and the anti-CD3 MAb. There were no significant differences between IL-2 production in PBMNCs from STCC patients after stimulation with PHA and in PBMNCs from healthy controls (P > 0.05). Patients without evidence of recurrence showed a significantly enhanced proliferative response in PBMNC to PHA and anti-CD3 MAb after intravesical prophylactic treatment with interferon-alpha 2b in the follow-up examinations 3 and 6 months after treatment (P < 0.01). However, three patients had evidence of tumour recurrence, and they showed no enhancement of the PBMNC proliferative response to these mitogens in the same examinations. In conclusion, the prophylactic intracavitary treatment of STCC with IFN-alpha 2b may induce a systemic immunomodulatory effect which is associated to the clinical evolution of the disease.

Aged↗
PubMed1994

Anisaldehyde production and aryl-alcohol oxidase and dehydrogenase activities in ligninolytic fungi of the genus Pleurotus.

A variety of simple aromatic compounds were identified in liquid cultures of the basidiomycetes Pleurotus cornucopiae, P. eryngii, P. floridanus, P. pulmonarius, P. ostreatus, and P. sajor-caju by using gas chromatography-mass spectrometry. Such compounds were detected in fungal cultures on lignin- and straw-containing media, but it was found that they were also produced in the absence of aromatic precursors. Anisylic and hydroxybenzylic compounds (such as alcohols, aldehydes, and acids) were identified, p-anisaldehyde being the most characteristic extracellular metabolite synthesized by these ligninolytic fungi. Small amounts of 3-chloro-p-anisaldehyde were also detected in several species. It is postulated that the balance between the more-or-less-oxidized aromatic compounds can be explained in terms of the activity of fungal enzymes, including aryl-alcohol oxidase and dehydrogenase. The former enzyme shows high affinity for p-anisyl alcohol, which is oxidized to p-anisaldehyde with production of H2O2. The aryl-alcohol dehydrogenase was detected only in the mycelium, where it reduces aromatic aldehydes in the presence of NADPH. Both enzymes could be involved in the redox cycling of these aromatic compounds, providing H2O2 to ligninolytic peroxidases.

Alcohol Oxidoreductases↗
PubMed1993

Chemical structure and conformational features of cell-wall polysaccharides isolated from Aphanoascus mephitalus and related species.

The structures of cell-wall mannans isolated from Aphanoascus mephitalus, A. fulvescens, A. verrucosus, and A. reticulisporus have been investigated by chemical analyses and 1D and 2D 1H and 13C NMR techniques. It was found that all of them consists of a relatively simple comb-like structure of the disaccharide repeating block [-->6)-[alpha-Manp-(1-->2)]-alpha-Manp-(1-->]. The conformations around the alpha-(1-->2) and alpha-(1-->6) linkages in these kinds of polymers were also studied by using molecular mechanics and dynamics calculations, together with NOE data. The results are similar to those found within the oligosaccharide chains of glycoproteins, with a well-defined conformation for the alpha-(1-->2) linkage and a certain restriction around the alpha-(1-->6) bonding imposed by the 2-substitution.

Ascomycota↗
PubMed1993

Severe chronic autoimmune thrombocytopenic purpura is associated with an expansion of CD56+ CD3- natural killer cells subset.

Recent studies have indicated that autoimmune thrombocytopenic purpura (ATP) patients show immune system alterations that are not restricted to the B-cell compartment, but that also affect T lymphocytes. This report studies the phenotypic characteristics of natural killer (NK) cells in the peripheral blood of ATP patients, as well as their clinical significance in 33 ATP patients with active disease. Ten patients had stable disease (sustained platelet counts > 50,000/microL without the need for treatment), whereas 23 patients had therapy-dependent disease (platelet counts < 50,000/microL). A significant increase in both CD56+ CD3- NK cells and CD56+ CD3+ cytotoxic T lymphocytes was observed in peripheral blood mononuclear cells and in purified CD2+ cells from therapy-dependent ATP patients as compared with ATP patients with stable disease and healthy controls. Moreover, there were more major histocompatibility complex (MHC) class II molecules in the CD56+ CD3- cells from the therapy-dependent patients' peripheral blood preparations than there were in the stable ATP patients' and healthy controls' peripheral blood preparations. This growth in the number of CD56+ CD3- NK cells was statistically higher in patients whose disease was refractory to conventional therapy (corticosteroids and splenectomy). In addition to the CD56+ CD3- NK cells, the percentage of CD3+ T lymphocytes and their proliferative response to phytohemagglutinin (PHA) stimulation were studied in fresh CD2+ preparations from nine patients with stable disease, 22 patients with therapy-dependent disease, and 26 healthy controls. The proliferative response of CD2+ lymphocytes from both groups was similar and significantly defective with respect to that found in healthy controls. In conclusion, clinically severe ATP (therapy-dependent disease) is associated with a significant increase of CD56+ CD3- NK cells, which is particularly marked in patients whose disease is refractory to therapy.

Adolescent↗
PubMed1993

Differences in cell wall polysaccharides of several species of Eupenicillium.

A beta-(1-5)-galactofuran was isolated and characterized from fraction F1S (alkali- and water-soluble) of the cell wall of most of the species of Eupenicillium. In E. cryptum, E. euglaucum and E. nepalense the galactan contained galactofuranose with different linkages in addition to beta-(1-5). Fraction F1I (alkali-soluble, water-insoluble) was an alpha-glucan in certain species while in others it was a beta-glucan. Xylose was detected in some species in F1I or in F3 (alkali-soluble at 70 degrees C). The most abundant fraction (F4), resistant to the alkali treatment, was a beta-glucan-chitin complex. Excepting this component, the beta-(1-5)-galactofuran was the polysaccharide which appeared more frequently in the cell wall of species of Eupenicillium and it may have chemotaxonomic relevance.

Carbohydrates↗
PubMed1993

Heterogeneous proliferative effect of tumor necrosis factor-alpha and lymphotoxin on mitogen-activated B cells from B-chronic lymphocytic leukemia.

The proliferative effect of tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin on B cells from patients with B-chronic lymphocytic leukemia (B-CLL) was studied. Fresh purified B-CLL lymphocytes showed no proliferative response to either recombinant (r) TNF-alpha or r-lymphotoxin. However, after "in vitro" activation of B-CLL lymphocytes for 2 days with Staphylococcus aureus Cowan 1 (SAC), four of seven patients showed enhanced blastogenic response in the presence of either rTNF-alpha or r-lymphotoxin. We also found that the proliferative response of SAC-activated B-CLL lymphocytes to the two cytokines was independent of that found in the presence of interleukin-2. These results demonstrate that TNF-alpha and lymphotoxin can heterogeneously support the proliferation of in vitro activated B cells from B-CLL patients and may reflect the biological heterogeneity of B-CLL disease.

B-Lymphocytes↗
PubMed1993

T lymphocytes from autoimmune thrombocytopenic purpura show a defective activation and proliferation after cytoplasmic membrane and intracytoplasmic mitogenic signals.

T lymphocyte activation and proliferation are complex cellular processes involving membrane and cytoplasmatic molecules as well as the secretion and response to cytokines, mainly interleukin 2. There is increasing evidence that autoimmune thrombocytopenic purpura (ATP) is associated with an alteration of the regulation of the immune system. The blastogenic response of purified T lymphocytes to mitogens that interact with membrane molecules (phytohemaglutinin, anti-CD3 monoclonal antibody) and with intracytoplasmic protein kinase C (phorbol myristate acetate) has been investigated in 22 ATP patients and 18 healthy controls. After the signal given by the three different mitogens [3H]-thymidine uptake in T lymphocytes from ATP patients was found to be significantly decreased with respect to that found in healthy controls under similar experimental conditions (P < 0.05). Analysis of the cell cycle progression in these T lymphocytes from ATP patients, showed a significantly diminished percentage of cells in S-phase after PHA stimulation (P < 0.05). The percentage of CD3+ cells in the CD2+ lymphocyte preparations was significantly decreased in ATP patients relative to healthy controls (P < 0.05). But there was no significant correlation between this percentage and the blastogenic response to PHA in the CD2+ cellular preparations from both groups of subjects. No significant differences were found in the percentages of CD4+ and CD8+ cells. These data indicate that the impaired blastogenic response of T lymphocytes from ATP patients may be ascribed to an intrinsic defect in these T cells. This defective proliferative response of T lymphocytes from ATP patients cannot be ascribed to either defective interleukin 2 production or receptor expression which were both similar to those of healthy controls (P > 0.05). And, the presence of saturating amounts of exogenous interleukin 2 did not normalize the defective proliferative response the mitogenic signals on the part of T lymphocytes from ATP patients. We conclude that T lymphocytes from ATP patients have a defective proliferative response to membrane and intracytoplasmatic mitogenic signals.

Adolescent↗
PubMed1993

The clinical outcome of autoimmune thrombocytopenic purpura patients is related to their T cell immunodeficiency.

In this work we have furthered the understanding of the alterations of T lymphocytes from 29 patients with active autoimmune thrombocytopenic purpura (ATP) and the clinical significance of their lymphocytes. An increased percentage of in vivo activated (CD25+ and DR+) T lymphocytes was found in ATP patients with respect to that found in 22 healthy controls. The function of these T cells measured as the proliferative response to polyclonal mitogenic signals is heterogeneously impaired in ATP patients. T lymphocytes from 65.5% (19/29) of the ATP patients showed a decreased proliferative response to these mitogenic signals. This functional alteration is associated with a redistribution of the T cell compartment in these patients' peripheral blood since a significant decrease of CD4+ T lymphocytes was found. We have also found that the impairment of the T cell function is different in the diverse clinical situations of the disease. Those with stable, untreated disease showed a marked decrease in the T cell proliferative response to mitogens. Furthermore, those patients who did not respond either to steroids or to splenectomy showed significantly reduced T lymphocyte blastogenesis after phytohaemagglutinin (PHA) stimulation in comparison to that found in responding patients.

Adolescent↗