Biomedical subjects

Y Pacheco

Publications and source records attributed to Y Pacheco.

At least 37 records · Page 2Linked to original sources

PubMed1996

Uptake of 12-HETE by human bronchial epithelial cells (HBEC): effects on HBEC cytokine production.

12-HETE, the major lipoxygenase end-product of platelets and macrophages, may be released in contact of bronchial epithelium in inflammatory diseases of the lung. We have studied the outcome of 12-HETE in presence of human bronchial epithelial cells (HBEC). When HBEC were incubated with [3H]12-HETE for 30 minutes, 27.5% of total radioactivity was found in HBEC and 72.5% in supernatants. Unesterified 12-HETE accounted for 22.4% of total radioactivity, 4.5% being recovered in phospholipids, preferentially in phosphatidylcholine and phosphatidylethanolamine. No incorporation in neutral lipids was detected. 72.9% of the incubated radioactivity was recovered in un identified metabolites. As 12-HETE has been shown to modulate the expression and production of various proteins, the consequence of the 12-HETE uptake on the release of GM-CSF and IL8 by HBEC was assessed. HBEC from control subjects were cultured for 24 hours with 12-HETE (10(-9) to 10(-7)M) in the presence or absence of TNF alpha. Detectable amounts of both cytokines were released in the supernatant in basal conditions at 24hr, and TNF alpha increased significantly the release of GM-CSF. 12-HETE at 10(-7)M weakly but significantly decreased the TNF-induced release of GM-CSF from HBEC. Thus the uptake of 12-HETE could affect the epithelial cell function in some situations.

Adult↗

PubMed1996

Antihistamines and production of granulocyte-macrophage colony-stimulating factor and interleukin-8 by human bronchial epithelial cells in vitro: evaluation of the effects of loratadine and cetirizine.

1. In this study, we compared the effects of two antihistamine drugs on the production of granulocyte-macrophage colony-stimulating factor and interleukin-8 by human bronchial epithelial cells in vitro. 2. Cytokine production was assessed by the use of an enzyme-linked immunosorbent assay. 3. Epithelial cells spontaneously released both cytokines and tumor necrosis factor alone induced a significant increase in this production but loratadine and cetirizine had no effect at the various concentrations studied. 4. The antihistamines have no effect and this suggests that histamine plays no role in cytokine production under these conditions.

Adult↗

PubMed1996

RU 41740 (Biostim) stimulates the production of granulocyte macrophage colony-stimulating factor and interleukin-8 by human bronchial epithelial cells in vitro.

1. In this study, we observed the effects of RU 41740 (Biostim) on the production of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-8 (IL-8) in human bronchial epithelial cells in vitro. 2. Cytokine production was assessed by enzyme-linked immunosorbent assay. 3. We report that epithelial cells spontaneously released both cytokines and that RU 41740 induced a significant increase in production of IL-8 and GM-CSF. 4. This is the first observation of a stimulatory effect of an immunostimulating compound used in humans on cytokine production by epithelial cells.

Adjuvants, Immunologic↗

PubMed1996

Increased respiratory burst and phosphodiesterase activity in alveolar eosinophils in chronic eosinophilic pneumonia.

A 43 year old woman presented with chronic eosinophilic pneumonia characterised by a high alveolar eosinophilic count, which allowed biochemical study of these cells. Alveolar eosinophils spontaneously produced high amounts of oxygen free radicals and exhibited an increased level of cyclic adenosine monophosphate (cAMP) phosphodiesterase (PDE) activity compared to blood eosinophils from control or allergic subjects. This activity was preferentially located in the plasma membrane, whilst the PDE activity of blood eosinophils from asthmatics or controls predominated in the cytosol. Because of the potential role of phosphodiesterase during eosinophil activation and recruitment, phosphodiesterase inhibitors may be useful in the treatment of eosinophilic pneumonia.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1996

[Vitamin A, conjunctival cytology and clinical complications in children hospitalized with pneumonia].

To study the possible relationship between vitamin A status and the severity of pneumonia, an analysis was made of serum retinol levels, conjunctival cytology, and clinical severity of the disease in 178 children admitted to a pediatric hospital in Havana for acute infectious pneumonia. The pneumonia was considered to be complicated (n = 57) when the patient presented pleural discharge, pulmonary abscesses, or both; if not, it was considered uncomplicated (n = 121). Serum retinol values in both groups were similar and were not found to be associated with the severity of the pneumonia. On the other hand, children with alterations in conjunctival cytology were twice as likely to have complicated pneumonia as those with normal cytology (relative risk = 2.2, with a 95% confidence interval of 1.1 to 4.5).

Adolescent↗

PubMed1995

Aerosolized interferon gamma for Mycobacterium avium-complex lung disease.

It has recently been shown that human alveolar macrophages can be selectively activated without systemic effect by the use of aerosolized interferon-gamma (IFN gamma), a cytokine that enhances macrophage oxidative and antimicrobial activity. We report the case of a 38-yr-old man negative for human immunodeficiency virus (HIV), with silicosis and advanced cavitary lung disease due to Mycobacterium avium intracellulare (MAI), who failed to improve despite 3 yr of continuous medical therapy with three or more drugs. He received three courses of aerosolized IFN gamma (500 micrograms 3 d per week for 5 wk in two courses and 200 micrograms 3 d a week for 5 wk after a short single trial of subcutaneous IFN gamma). The numbers of MAI decreased in the sputum during therapy, but cultures of the organism remained positive at the same level for the first two treatment periods. The patients sputum became AFB smear negative and the number of colonies decreased significantly after the third course of IFN gamma therapy. Cessation of IFN gamma was associated with a rapid increase in the numbers of MAI in the sputum. Aerosolized IFN gamma can be considered as an adjuvant to conventional drug therapy, with a good tolerance, in cases of lung disease caused by resistant MAI.

Administration, Inhalation↗

PubMed1994

Decreased arachidonic acid metabolism in human platelets by autologous neutrophils: possible role of cell adhesion.

The amount of the 12-lipoxygenase and cyclo-oxygenase products, 12(S)-hydroxy-(Z,Z,E,Z)-5,8,10,14-eicosatetraenoic acid (12-HETE) and 12(S)-hydroxy-(E,E,Z)-5,8,10-heptadecatrienoic acid (HHT), in human platelets stimulated by thrombin (0.1 and 2.5 units/ml), was studied in the presence of autologous neutrophils. A decreased formation of both products was induced by unstimulated neutrophils or neutrophils challenged with N-formylmethionyl- leucyl-phenylalanine (0.1 microM) or Ca2+ ionophore A23187 (0.15 microM). The effect of neutrophils was observed only in the presence of Ca2+. 12-HETE and HHT were also produced in platelets stimulated with thrombin in the absence of Ca2+ and/or Mg2+, but their level was not altered by neutrophils. 12(S),20-Dihydroxy-(Z,Z,E,Z)-5,8,10,14-eicosatetraenoic acid (12,20-DHETE), the cytochrome P-450 product from 12-HETE in neutrophils, was hardly detected, and its level did not compensate for the decrease in 12-HETE observed after platelet and neutrophil co-incubation. 5(S),12(S)-Dihydroxy-(E,Z,E,Z)- 6,8,10,14-eicosatetraenoic acid (5(S),12(S)-DHETE), the 5-lipoxygenase product of 12-HETE in neutrophils, was never detectable. In addition, the inhibition of 12-HETE and HHT formations appeared not to be due to degradation or thrombin uptake by neutrophils, nor was the decrease observed when the two cell populations were physically separated. A monoclonal antibody against the human platelet glycoprotein GMP140 (CD62), mediating Ca(2+)-dependent platelet-neutrophil adhesion, mimicked the inhibitory effect of neutrophils in a dose-dependent fashion. Furthermore, the 12-HETE and HHT productions were not affected when platelets were stimulated in the presence of neutrophils previously incubated with sialidase, which removes the sialic acid from a sialyl Lewis(x) structure assumed to be the neutrophil receptor for platelet GMP140. We conclude that the decrease in thrombin-stimulated 12-HETE and HHT formation observed when platelets were co-incubated with autologous neutrophils might be the consequence of platelet-neutrophil adherence, presumably through platelet GMP140.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1994

Antibiotics and production of granulocyte-macrophage colony-stimulating factor by human bronchial epithelial cells in vitro. A comparison of cefodizime and ceftriaxone.

Cultured human bronchial epithelial cells (HBEC) produce both granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 8 (IL-8). The influence of cefodizime (CAS 69739-16-8), a new broad spectrum cephalosporin with immunostimulatory effects, and ceftriaxone on the production of GM-CSF and IL-8 in HBEC primary cultures was investigated. HBEC were isolated from biopsy specimens obtained during fibreoptic bronchoscopy in 12 patients (most frequent diagnosis: chronic bronchitis). Confluent monolayers of HBEC cultured on collagen were incubated for 24 h in a medium without study drugs (spontaneous production) or containing cefodizime or ceftriaxone at the clinically relevant concentrations of 1, 10 and 100 mg/l, with or without tumor necrosis factor alpha (TNF alpha, 100 U/ml). GM-CSF and IL-8 were measured in supernatant by ELISA technique. TNF alpha alone led to a significant (p < 0.005) increase in both GM-CSF and IL-8 production. Cefodizime induced a significant (p < 0.05), dose-dependent increase in GM-CSF release. No additive effect of cefodizime with TNF alpha was observed. Cefodizime did not affect IL-8 production and ceftriaxone had no influence on cytokine production. This is the first report of a stimulatory effect of a beta-lactam antibiotic on cytokine production by epithelial cells. GM-CSF production by epithelial cells is an important immunological step for neutrophil and monocyte recruitment and cell priming during lung defence. Previous studies with cefodizime in immunodepressed subjects have shown activation of phagocytosis and phagocytosis-related functions in non-lung phagocytes. An indirect mechanism of action, similar to that indicated by our results, may have been responsible for these stimulatory effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Behaviour of leukocyte membrane fluidity in presence of anaesthetic drugs. Comparison between allergic patients and control subjects.

1. In this study we compared the effects of two anaesthetic drugs on the leukocyte membrane fluidity in allergic patients versus control subjects. 2. Fluidity was assessed by means of the fluorescence polarization technique. 3. We report that the treatment of the whole leukocytes with thiopental or pancuronium enhanced membrane fluidity in the allergic group as well as in the control one, but the effect was more pronounced in allergics. 4. This finding suggests a different biophysical behaviour of the leukocyte membrane towards anaesthetic drugs in allergic diseases. 5. This agrees with the hypothesis of the existence of an intrinsic abnormality in allergic cells, expressed as an initial hyperreactive state.

Adult↗

PubMed1993

Increased plasma levels of atrial natriuretic factor, renin activity, and leukotriene C4 in chronic obstructive pulmonary disease.

We studied atrial natriuretic factor (ANF), plasma renin activity (PRA), and plasma levels of leukotrienes (LTs) B4 and C4 in 23 patients with COPD undergoing right cardiac catheterization for suspected pulmonary hypertension. Hemodynamic measurements together with concomitant ANF levels (both in venous and pulmonary artery blood and right atrial and pulmonary artery plasma levels of LTC4 and LTB4, were determined at rest (T0), after 30 min of breathing oxygen (3 L/min) (T1), and after 30 min recovering and breathing air (T2). Patients with effective exacerbation or definitive evidence of left ventricular disease, hypertension, arrhythmias, or vasodilator or diuretic therapy were excluded. Increased levels of ANF, both in peripheral venous blood (117 +/- 65 pg/ml) and the pulmonary artery (153 +/- 75 pg/ml), were found in patients with COPD, with or without pulmonary hypertension. Levels of LTC4 were also significantly increased (366 +/- 406 pg/ml) when compared with our control values. No correlations among ANF, LTC4 values, functional tests, and hemodynamic measurements were found. Brief increased levels of oxygen did not modify ANF or LTC4 plasma levels, either in patients with or without pulmonary hypertension.

Atrial Natriuretic Factor↗

PubMed1993

Concentrations of cefodizime in bronchial secretions after single intravenous administration.

UNLABELLED: The concentrations of cefodizime (HR 221, CAS 69739-16-8) in bronchial secretions were measured after administration of a single intravenous bolus of 2 g in 19 patients requiring fibreoptic bronchoscopy for diagnostic purposes or as therapeutic follow-up. These concentrations, which were obtained in absence of inflammation of the mucosa, were compared to serum concentrations obtained simultaneously. The penetration into bronchial secretions was rapid, maximum levels of between 1 and 5 mg/kg being already observed 1 h after injection. Most concentrations remained about 1 mg/kg throughout the whole observation period of about 5.5 h. The percent penetration amounted to about 1.5% of the corresponding serum concentrations. CONCLUSION: Concentrations well above the MIC90s of the relevant respiratory pathogens--S. pneumoniae, M. catarrhalis, H. influenzae, K. pneumoniae--and Enterobacteriaceae were reached in bronchial secretions after intravenous injection of a single 2 g dose of cefodizime. Even higher levels may be expected in the usual condition of inflamed bronchial mucosa as found in respiratory infections.

Adult↗

PubMed1992

Leukotriene B4 level in stimulated blood neutrophils and alveolar macrophages from healthy and asthmatic subjects. Effect of beta-2 agonist therapy.

Leukotriene B4 levels were measured after stimulation by calcium ionophore A23187: (i) in peripheral, neutrophils (PMN) from allergic asthmatics, rhinitis and healthy subjects; (ii) in macrophages collected by bronchoalveolar lavage. LTB4 levels in PMNs were significantly higher in non-treated allergic asthmatics and non-treated subjects with rhinitis compared to controls. Beta-2 agonist-treated asthmatics showed a significantly decreased LTB4 production which was not different from those of controls. In vitro, LTB4 production decreased significantly after PMN incubation with Salbutamol (10(-6) mol l-1). LTB4 produced by AM collected by BAL was measured in non-treated (n = 5) and treated (n = 11) asthmatics with inhaled beta-2 agonist. AM collected from all controls and non-treated asthmatics produced LTB4. By contrast, no production of LTB4 was observed in the treated group. LTB4 production decreased when normal AM were incubated in vitro with Salbutamol (10(-8) mol l-1). These results suggest that biochemical differences occur in PMN and macrophages from subjects treated with beta-2 agonist, presumably in changing the 5-lipoxygenase pathway.

Adult↗

PubMed1992

[Comparison of 2 cisplatin and etoposide dosages in relapsing small cell lung cancer].

The synergistic combination of cisplatinum and etoposide appears as the best second line treatment in patients relapsing from small cell lung carcinoma (SCLC). In order to test the dose-effect relationship of cisplatinum and etoposide in this situation, we have performed a randomised phase II trial comparing 2 five-day regimens: cisplatinum 20 mg/m2/day+etoposide 60 mg/m2/day (arm A) versus cisplatinum 40 mg/m2/day+etoposide 100 mg/m2/day (arm B) every 4 weeks. Thirty-seven patients were included (arm A: 18, arm B: 19), and 32 were considered to be eligible (arm A: 15, arm B: 17). Eight patients were non evaluable, five of them because of toxic death occurring prior to the second course (arm A: one from neutropenia; arm B: three from neutropenia and one from thrombopenia). The two groups were well balanced with regard to the main prognostic factors (age, sex, performance status, LDH level, response to induction chemotherapy). An objective response was observed in 10/24 evaluable patients (arm A: 4, arm B: 6) and was considered as complete in one patient in arm A and in 2 pts in arm B; these two patients presented with cerebral metastases and their response lasted 9 and 15 weeks respectively. The mean duration of response was 11 weeks in arm A and 10.5 weeks in arm B. The median actuarial survival of the overall population of eligible patients was 15 weeks: 13 weeks in arm A and 16.5 weeks in arm B. The study was discontinued because of the 23.5% toxic deaths rate in the high doses arm in this heavily pre-treated population of patients. However, the high response rate (54% overall, 35% considering toxic death as a failure) is impressive and presents evidence for the dose/effect relationship in SCLC.

Aged↗

PubMed1991

Leukotriene B4 level in neutrophils from allergic and healthy subjects stimulated by low concentration of calcium ionophore A23187. Effect of exogenous arachidonic acid and possible endogenous source.

Peripheral blood neutrophils from patients with allergic rhinitis and from normal subjects were incubated for 5 min at 37 degrees C with 0.15 microM calcium ionophore A23187 in the absence or presence of exogenous arachidonic acid (2.5 to 10 microM). In neutrophils from allergic patients, the leukotriene B4 (LTB4) level was significantly increased by exogenous arachidonic acid in a concentration-dependent manner (16.2 +/- 4.2 and 38.1 +/- 6.8 pmol/5 min per 2 X 10(6) cells in the absence and presence of 10 microM arachidonic acid, respectively; P less than 0.005; n = 8). The LTB4 level in neutrophils from healthy subjects was only 0.97 +/- 0.17 pmol/5 min per 2 x 10(6) cells (n = 5) and was not enhanced by exogenous arachidonate. When cells from allergic patients were challenged in the presence of exogenous [1-14C]arachidonic acid, released LTB4 was radiolabeled and the incorporated radioactivity increased with the labeled arachidonate concentration. Labeled LTB4 was never detectable after incubating neutrophils from normal donors with exogenous labeled arachidonate. When neutrophils were incubated with [1-14C]arachidonate for 1 h, the different lipid pools of the two cell populations were labeled but both types of neutrophils produced unlabeled LTB4 in response to ionophore stimulation. The hydrolysis of choline and ethanolamine phospholipids into diacyl-, alkenylacyl- and alkylacyl-species revealed that solely the alkylacyl-subclass of phosphatidylcholine was unlabeled. We conclude (i) that neutrophils from allergic patients stimulated by low ionophore concentration produce more LTB4 than neutrophils from healthy subjects and incorporate exogenous arachidonate, (ii) that endogenous arachidonate converted to LTB4 by the 5-lipoxygenase pathway may provide only from 1-O-alkyl-2-arachidonoyl-glycero-3-phosphocholine.

Adult↗

PubMed1991

Leukotriene B4 levels from stimulated neutrophils from healthy and allergic subjects: effect of platelets and exogenous arachidonic acid.

Leukotriene B4 (LTB4) levels were measured in peripheral blood neutrophils from allergic and healthy donors after stimulation by calcium ionophore A 23187. This level was higher in neutrophils from allergic subjects than in neutrophils from healthy subjects in the presence as well as in the absence of exogenous arachidonic acid. Platelets from allergics increased LTB4 levels from neutrophils from allergics but not levels in those from healthy donors. Moreover, platelets from healthy subjects reduced LTB4 in neutrophils from both groups. These results suggest that biochemical differences exist in neutrophils and platelets from allergics which contribute to changes in arachidonic acid metabolism via the 5-lipoxygenase pathway. In addition, they support the concept that platelets may play an important role in the regulation of neutrophil LTB4 levels, possibly by affecting the 5-lipoxygenase activity during the course of allergic inflammatory reactions.

Adolescent↗

PubMed1991

[Asthma and infection: interrelations].

The frequent interaction of infection in asthma is a result of a complex interrelationship. Infectious agents are capable both of inducing asthmatic crises and, at least for viruses, of initiating the asthmatic process. They also favour a specific IgE response to allergens. Similar immunity is involved in defence against these infectious agents but this immunity can be disturbed in asthmatic subjects; as seen with defects in immunoglobulin subclasses, disturbance in T lymphocyte function, monocytes and blood neutrophils. The determination of the genetic or acquired character of these disturbances is pre-condition for the development of a therapeutic substitute.

Asthma↗

PubMed1990

Alteration of membrane phospholipid methylation by adenosine analogs does not affect T lymphocyte activation.

Membrane phospholipid methylation has been described during activation of various immune cells. Moreover recent data indicated modulation of immune cells functions by adenosine. As S-Adenosyl-methionine and S-Adenosyl-homocysteine are adenosine analogs and modulators of transmethylation reactions, the effects of SAH and SAM were investigated on membrane phospholipid methylation and lymphocyte activation. SAM (10(-5) M) was shown to induce the membrane phospholipid methylation as assessed by the 3H-methyl-incorporation in membrane extract. This effect was inhibited by SAH. In contrast SAM and SAH did not affect the phytohemagglutinin-induced proliferative response of peripheral blood mononuclear cells. SAH neither modified the early internalization of membrane CD3 antigens nor did it prevent the late expression of HLA-DR antigens on lymphocytes activated by phytohemagglutinin. These results indicate that in vitro alteration of phospholipid methylation does not affect subsequent steps of human T lymphocyte activation and proliferation.

Adenosine↗

PubMed1990

Cyclic nucleotide phosphodiesterases and methyltransferases in purified lymphocytes, monocytes and polymorphonuclear leucocytes from healthy donors and asthmatic patients.

Cyclic nucleotide phosphodiesterase and phospholipid N-methyl-transferase activities were simultaneously measured in purified polymorphonuclear cell-, mononuclear cell-, lymphocyte- and monocyte-homogenates from control subjects, from patients with atopic asthma and from patients with non-atopic asthma. Whereas cyclic AMP and cyclic GMP phosphodiesterase activities were found to be about 10-fold lower in polymorphonuclear than in mononuclear cells, phospholipid N-methyltransferase proved to be rather similar in each cell type from control donors. Cyclic AMP phosphodiesterase and phospholipid N-methyltransferase were significantly decreased in polymorphonuclear cells and monocytes from asthmatic patients compared with the control group while cyclic GMP phosphodiesterase was significantly impaired only in the monocyte subpopulation.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗