PubMed Health⌕ Search

Biomedical subjects

A Prieto

Publications and source records attributed to A Prieto.

At least 73 records · Page 4Linked to original sources
PubMed1997

An extract of the fern Polypodium leucotomos inhibits human peripheral blood mononuclear cells proliferation in vitro.

An alcoholic extract of the fern polypodium leucotomos (PLE) has been empirically used as an immunosuppressor for the treatment of several autoimmune diseases. In this paper, we investigated the effects of PLE on activation and proliferative responses of peripheral blood mononuclear cells (PBMNC) from healthy donors to T lymphocyte polyclonal mitogens. PLE shows a significant inhibitory effect on the proliferative response of PBMNC to stimulation with phytohaemagglutinin (PHA) or anti CD3 monoclonal antibodies (p < 0.05). In contrast, PLE did not modify the proliferative response of PBMNC to phorbol esters (p > 0.05). The inhibitory effect of PLE upon mitogen induced PBMNC proliferation is time dependent and can be overcome by the exogenous addition of interleukin-2 to the culture medium (p < 0.05). The decreased proliferative response of PBMNC to PHA stimulation in the presence of PLE is not associated with a significant modification of expression of the alpha chain (CD25) of the IL-2 receptor (p > 0.05). In conclusion, PLE shows an inhibitory effect on the polyclonal proliferative response of PBMNC to T lymphocyte mitogens that interact with cytoplasmic membrane molecules.

Adult↗
PubMed1997

Thymostimulin increases natural cytotoxic activity in patients with breast cancer.

The effect of thymostimulin on the Natural Killer (NK) cytotoxic activity of peripheral blood mononuclear cells (PBMC) was investigated in 15 patients with breast cancer after finishing or during chemotherapy (CAF) and in 10 healthy controls. PBMC from these subjects were incubated in the presence of thymostimulin for varying periods of time (18 h or 5 days), and then used as effector cells against 51Cr-radiolabeled NK-sensitive (K-562) and NK-resistant (JY) target cells in cytotoxicity assays. No significant differences were observed between the NK-activity from breast cancer patients and healthy controls. Thymostimulin induced a dose- and time-dependent cytotoxic enhancing effect on the cytotoxic activity of PBMC from these patients against NK-sensitive K562 target cells. The thymostimulin (1000 ng/ml) significantly enhanced cytotoxic activity in PBMC from breast cancer patients who had previously received chemotherapy (p = 0.0277) against NK-sensitive cells. This increase was not statistically significant neither in PBMC from patients receiving chemotherapy nor in healthy controls (p > 0.05 in both cases). The incubation of PBMC from patients with breast cancer was not associated to a significant enhancement of the cytotoxic activity against NK-resistant target cells (p > 0.05). We also found that thymostimulin could synergize with interleukin-2 in inducing NK cytotoxic activity in PBMC after 18 h of culture (p = 0.0277). In conclusion, we have demonstrated that thymostimulin enhances the natural killer cytotoxic activity of PBMC from patients with breast cancer who have previously received chemotherapy.

Adjuvants, Immunologic↗
PubMed1997

Acute bilateral extradural haematoma of the posterior cranial fossa.

Traumatic haematomas located in the posterior fossa are less frequent than those above the tentorium. Extradural haematomas are the most common type of haematomas in the posterior fossa and are usually unilateral. We present the case of a patient with a bilateral extradural haematomas of the posterior fossa and review eight cases previously reported in the literature.

Brain Concussion↗
PubMed1997

Serum tryptase levels in adverse drug reactions.

We evaluated the usefulness of individual tryptase levels and variations after adverse drug reactions in 64 patients. Our aim was to find a tool for the diagnosis of drug allergy. Thirty-seven subjects were confirmed to have drug allergy, 12 had nonsteroidal anti-inflammatory drug (NSAID) reactions, five had negative controlled drug challenges (NAAR), and 10 had symptoms after placebo intake (PLA). Serum tryptase levels greatly increased after anaphylactic shocks (2242%) and anaphylaxis (710.5%). Patients with allergic urticaria and those with idiosyncratic responses to acetylsalicylic acid (ASA) exhibited a small increase in serum tryptase (49.5% and 38.2%, respectively). In the other two groups (NAAR and PLA), no variation in this serum protease was observed. The time of appearance of the serum tryptase peak differed considerably among patients with similar clinical reactions (from 30 min to 6 h) and was independent of the latent period, severity of symptoms, or the amount of tryptase released. We conclude that serum tryptase determinations are helpful in the diagnosis of anaphylactic shock and anaphylaxis, but serial measurements may be needed to confirm mast-cell participation in milder reactions.

Anaphylaxis↗
PubMed1997

T lymphocytes infiltrating the bladder wall of patients with carcinoma of urinary bladder are in vivo activated.

OBJECTIVES: This paper studies the phenotypical characteristics of the lymphocytes present in mononuclear cell (MNC) preparations from peripheral blood (PBMNC), lymph nodes (LNMNC), tumor bladder (TBMNC), and tumor-free bladder (TFBMNC) from patients with infiltrated transitional cell carcinoma (TCC) of the bladder and PBMNC of healthy controls. METHODS: Eight patients diagnosed with TCC of the bladder, according to UICC criteria, and 10 healthy controls were studied. For immunofluorescence staining, T lymphocytes were incubated with combinations of fluorescein (FITC, green)- and phycoerytrin (PE, red)-labelled monoclonal antibodies. RESULTS: The percentage of NK cells in the LNMNC and TFBMNC was significantly decreased in comparison to that found in the PBMNC from these patients (p < 0.05). A significant enhancement of the expression of class II molecules of the major histocompatibility complex (MHC) by CD3+ T lymphocytes from TBMNC and TFBMNC specimens from bladder walls was found with respect to those quantified in CD3+ T lymphocytes from PBMNC (p < 0.05). In addition, the percentage of CD3+CD25+ T lymphocytes was significantly higher in PBMNC in TCC patients than in healthy controls (p < 0.05). CONCLUSIONS: Our data clearly demonstrate that the presence of infiltrative TCC of the bladder is associated to an infiltration of in vivo activated T lymphocytes of the urinary bladder wall. This in vivo T lymphocyte activation has been considered an expression of the immune response against the tumor cells.

Aged↗
PubMed1996

Structural characterization of extracellular polysaccharides produced by fungi from the genus Pleurotus.

The extracellular polysaccharides produced in liquid cultures of the ligninolytic fungi Pleurotus cornucopiae, P. eryngii, P. floridanus, P. ostreatus, P. pulmonarius and P. sajor-caju showed similar composition and structure. They included a minor water-soluble fraction, containing D-glucose, D-mannose, D-galactose and protein (rich in amide- and hydroxyl-containing residues which can be involved in protein-polysaccharide linkages). The structural analysis of this fraction mainly showed alpha-(1-->4)-linked glucose units. The structure of the major fraction (amounting to more than 80% of the total extracellular polysaccharide) was investigated in detail. Its low solubility was attributed to the high M(r). For its characterization a procedure of progressive dissolution and dialysis was set up. The methylation analysis showed that it was a (1-->3)-beta-D-glucan and that approximately 25% of the total units were C-6 branched. This result was confirmed by the intensities of the signals assigned to C-3 and C-6, free and substituted, in 13C-NMR spectra. Additional studies showed linear polysaccharides after one-cycle Smith degradation or after glucan acetolysis. Both results, as well as glucose release after the latter treatment, indicated that the C-6 linked side chains are constituted by single glucose residues, on every second or third unit of the main chain of the (1-->3)-beta-D-glucan.

Carbohydrate Conformation↗
PubMed1996

Defective interferon-gamma production by T-lymphocytes from patients with acute brucellosis.

The authors investigated the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) by phytohaemagglutinin (PHA)-stimulated T-lymphocytes from 21 untreated patients with acute brucellosis. PHA-stimulated T-lymphocytes from acute brucellosis patients showed normal IL-2 production but defective IFN-gamma production (brucellosis patients 531 +/- 103 pg mL-1 vs. healthy controls 1024 +/- 212 pg mL-1) after 72 h of culture. This altered pattern of IL-2 and IFN-gamma production by T-lymphocytes was observed in seven brucellosis patients whose T-lymphocytes exhibited a normal proliferative response to PHA (61 612 +/- 18 422 cpm) as well as in the 14 patients with a defective T-lymphocyte proliferative response to the PHA after 5 days of culture (19 479 +/- 4409 cpm). After antibiotic therapy, production of the two lymphokines by the PHA-stimulated T-lymphocytes from acute brucellosis patients was similar to that of T-lymphocytes from healthy control subjects. The authors conclude that PHA-stimulated T-lymphocytes from untreated patients with acute brucellosis have defective INF-gamma production but normal IL-2 production.

Acute Disease↗
PubMed1996

An antigenic water-soluble glucogalactomannan extracted from cell walls of Paecilomyces fumosoroseus and Paecilomyces farinosus.

The water-soluble fraction (F1S) obtained after solubilizing in alkali the cell walls of four strains of Paecilomyces fumosoroseus and two of Paecilomyces farinosus amounted to 8.3-14.5% of the dry cell wall material. Two polysaccharides, F1S-A (13-20%) and F1S-B (57-68%) were separated from F1S by gel permeation through Sepharose CL-6B. 1H and 13C NMR spectra of F1S-B were recorded and showed analogous structural features in the six isolates of the two species. The fractions isolated from P. fumosoroseus strain CBS 375.70 were subjected to structural analysis and shown to be a (1-->4)-alpha-glucan (F1S-A) and a branched (1-->6)-mannan with terminal residues of beta-galactopyranose (F1S-B). Polyclonal antibodies against the latter polysaccharide were obtained (titre 1/8000). These antibodies reacted specifically with the F1S-B polysaccharides obtained from the four strains of P. fumosoroseus and the two strains of P. farinosus, but they did not react with similar fractions from other species of the same or related genera. The antibodies specifically stained P. fumosoroseus hyphae in indirect immunofluorescence tests.

Antigens, Fungal↗
PubMed1996

Increased production of interleukin-6 by T lymphocytes from patients with multiple myeloma.

Alterations in T lymphocyte functions may affect other cellular components of the immune system. Several lymphokines produced by T cells are involved in the proliferation and differentiation of human B lymphocytes. Alterations in the secretion of these molecules may be implicated in the development of B cell lymphoproliferative diseases. We have investigated the production of interleukin-2 (IL-2) and interleukin-6 (IL-6) by T lymphocytes from 14 patients with multiple myeloma (MM) and 16 healthy controls. The phenotypical and functional characteristics of these T lymphocytes were also studied. The proliferative response to vegetal lectin phytohemagglutinin (PHA) stimulation was decreased in T lymphocytes from MM patients (p < 0.01). This defective proliferative response cannot be ascribed to either defective IL-2 production or diminished receptor expression, since neither of these parameters showed a significant difference between MM patients and healthy controls (p < 0.05). However, the defective proliferative response of T lymphocytes from MM patients was reverted by the addition of saturating amounts of exogenous IL-2 (p > 0.05) but not by exogenous IL-6 (p < 0.05). The IL-6 production by PHA-stimulated T lymphocytes from the MM patients was significantly higher than in healthy controls (p < 0.01). We conclude that T lymphocytes from MM patients show a functional alteration with a defective proliferative response to PHA that is reverted by exogenous addition of IL-2. After lectin stimulation, the production of IL-2 by T lymphocytes from those patients was normal, while IL-6 secretion was increased.

Aged↗
PubMed1996

[Cervical intramedullary neurofibroma].

Spinal neurofibromas make up a third of all tumours of the medulla. They are usually found to be intradural and extramedullary. Exceptionally they may be intramedullar. We describe the case of a patient with signs of slowly progressive compression of the medulla, who was operated on surgically for an intramedullary neurofibroma, after imaging studies. We review the previously published cases and analyse the different histogenic theories concerning this tumour.

Female↗
PubMed1995

Abnormal gamma IFN and alpha TNF secretion in purified CD2+ cells from autoimmune thrombocytopenic purpura (ATP) patients: their implication in the clinical course of the disease.

Gamma inferferon (gamma IFN), alpha tumor necrosis factor (alpha TNF), and interleukin 6 (IL-60) are cytokines produced by a wide variety of cells, including T lymphocytes and NK cells. These cytokines affect B-cell proliferation and differentiation into immunoglobulin secreting cells. In addition, gamma IFN and alpha TNF also enhance the function of macrophages, upregulating the expression of their IgG receptors. Abnormalities in the production of these cytokines may be involved in the clinical course of autoimmune thrombocytopenic purpura (ATP). This paper describes the production of these cytokines in PHA-stimulated peripheral blood CD2+ cells from ATP patients. Both gamma IFN and alpha TNF were significantly increased in PHA-stimulated CD2+ cells from therapy-dependent ATP patients (platelet counts < 50,000/microliter), as compared to ATP patients with stable disease (sustained platelet counts < 50,000/microliter without need treatment) (P < 0.05). No significant differences were found in gamma IFN production by PHA-stimulated CD2+ cells between therapy-dependent ATP patients and healthy controls (P < 0.05). However, the production of alpha TNF by PHA-stimulated CD2+ cells from therapy-dependent ATP patients was significantly higher compared to that found in healthy controls (P < 0.05). There were no significant differences in IL-6 production by PHA-stimulated CD2+ cells from ATP patients and healthy controls (P < 0.05). These findings demonstrate abnormal gamma IFN and alpha TNF secretion in purified CD2 cells from ATP patients. The clinical severity of the disease is associated with the altered secretion of these lymphokines by CD2 cells.

Adolescent↗
PubMed1995

Congenital intracranial filariasis: a case report.

We present the case of a newborn with intracranial extra-axial collections which mere partially calcified. The underlying cause was shown to be filariasis which had been transmitted from the mother.

Adult↗