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Y Pacheco

Publications and source records attributed to Y Pacheco.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Pulmonary sarcoidosis. Study of the distribution of active alveolitis assessed by comparison of data from radiological examination, gallium 67 scintigraphy and double bronchoalveolar lavage].

Abnormal uptake of gallium in alveolar structures, raised lymphocyte levels, ECA and, to a lesser degree, proteins in alveolar washings are the principal currently known criteria used to recognise cases of sarcoidosis with persistent immunological activity. The contribution of data concerning broncho-alveolar washings (BAW) in the context of this diagnostic assessment has never been the subject of a critical evaluation. It would nevertheless seem that the distribution of sarcoidosis lesions is not always diffuse and homogeneous, leading to the possibility of errors of assessment in this technique. The aim of the present study was to assess the true existence, degree and consequences of this risk. It was based upon the study of 41 cases of active pulmonary sarcoidosis. Search for homogeneity and heterogeneity between lesions and active alveolitis involved precise radiological study, gallium isotope scan with determination of the index of uptake as well as the quality of the latter, and double BAW carried out in the most radioactive and least radioactive regions respectively. Comparative study of the results obtained showed that zones of active alveolitis were distributed unevenly and heterogeneously in more than half of the patients (71% for gallium and 54% for BAW). This would explain the fact that in 14 cases (34%) criteria of alveolar activity were present in only one of the two specimens of washings. Identification of the zones which should be included in BAW cannot be determined accurately by radiological analysis, regardless of the degree and distribution of radiological abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Membrane phosphatidylethanolamine methylase in blood leukocytes and alveolar macrophages of asthmatic patients].

Phosphatidyl ethanolamine methylase (PEMT) is an enzyme involved in the methylation of membrane phospholipids which plays a very important role in the modulation of the activity of the beta-receptors and the production of phosphatidylcholine, substrate of phospholipase A2. This report describes a study of PEMT on the membranes of blood leucocytes and alveolar macrophages obtained by bronchoalveolar washings in different types of asthma: allergic, intrinsic and occupational. This was accompanied by parallel study of respiratory function tests and the level of bronchial reactivity to carbachol in asthma sufferers as well as other alveolar biological parameters: phospholipid fractions of surfactant, angiotensin conversion enzyme and protein/albumin ratio. The authors found a significant increase (in comparison with controls) in PEMT activity both in macrophages and leucocytes in cases of intrinsic asthma. However, there was no correlation between the level of activity of the enzyme and the degree of bronchial hyper-reactivity. There was no change in alveolar phospholipid environment. In the light of these findings, the role of membrane activation of the alveolar macrophage is discussed in the physiopathology of intrinsic asthma.

Adult↗
PubMed1984

Activity of cyclic AMP phosphodiesterase and methyltransferases in leukocyte membranes from allergic patients.

Cyclic AMP metabolism and methylation of phospholipids are central events which occur at the membrane level. Since a dysfunction of cell membranes seems to characterize some allergic diseases, we investigated cyclic AMP phosphodiesterase and methyltransferase activities in leukocyte membrane fractions obtained from healthy volunteers and from allergic patients. The allergic group presented a significantly decreased methyltransferase activity compared with a control group, whereas cyclic AMP phosphodiesterase and noradrenaline (NA)-stimulated methyltransferase were found to be increased with respect to the control group. A significant correlation has been found between cyclic AMP phosphodiesterase and NA-stimulated methyltransferase with both control and allergic subjects, which suggests close relationships between these two enzymes within the cell membrane.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

Modulation by S-adenosyl-methionine and S-adenosyl-homocysteine of the human leucocytes histamine release.

Methylation of membrane phospholipids is an important stage in the process of histamine release. This methylation reaction can be modulated by S-adenosyl-methionine (SAM) as well as by S-adenosyl-homocysteine (SAH). The influence of SAM and of SAH upon the histamine release of leucocytes from asthmatic and normal subjects were compared. In concentration of 10(-4) M, SAM enhanced spontaneous and the specifically induced histamine release. In concentration of 10(-5) M SAM enhanced the histamine release only in normals. This phenomenon could indicate a deficit in methyl-transferase activity in the asthamatics. In concentration of 10(-4) M, SAH reduced spontaneous and specifically induced histamine release, having an effect comparable to that of 10(-4) M Theophylline.

Allergens↗
PubMed1983

Phosphatidyl ethanolamine methylation in membrane from bronchoalveolar lavage mononuclear cells, in asthmatic patients: a new marker of macrophage activity.

Phosphatidyl ethanolamine methylation was compared in alveolar macrophage membrane from asthmatic and control subjects. Phosphatidyl ethanolamine methylase activity was determined by measuring the incorporation of (3H) methyl group from (3H) adenosyl methionine into membrane phospholipids. (3H) methyl group incorporation was significantly higher in macrophages from asthmatic patients. This result is consistent with macrophage membrane activation and could signify: a membrane phospholipid pool regeneration after allergenic or toxic disturbance or an enzymatic activation by inflammatory mediators.

Adult↗
PubMed1983

[Lymphomatoid granulomatosis and hypersensitivity pneumopathy. Clinical and biological study (serum and alveolar) toward a new pathogenic hypothesis of the disease].

The authors discussed the malign form of lymphomatoid granulomatosis on the basis of two cases and consider the possible role of an aerocontaminant which is usually responsible for the extrinsic allergic type of alveolitis. A detailed biochemical and cytological study of the alveolar fluid from one of these patients is presented in parallel with immunofluorescent histology and electron microscopy of the lung. The observed biochemical abnormalities in the alveolar fluid could be superimposed on those formed in certain types of hypertensive lung disease. On the other hand the cytology was different, the cytofluorimetric technique revealed a mononuclear cell population rich in RNA whose role in the genesis of the disease of malign nature are discussed. The hypothesis of a hypersecretion of IgA by this malign process is raised by immunofluorescent studies of the lung. The role of IgA in lymphomatoid granulomatosis and bird fanciers lung is discussed in the light of recent work on pigeon IgA.

Adult↗
PubMed1982

Flow cytometry analysis of T lymphocytes in sarcoidosis.

To examine the immunologic alterations in patients with sarcoidosis we characterized the cell cycle phase of T lymphocytes that were collected from peripheral blood and from bronchoalveolar lavage fluid. T-cell DNA and RNA contents were measured at the single cell level using flow cytometry after staining with the metachromatic fluorochrome acridine orange. T-enriched lymphocyte suspensions were obtained from peripheral blood and from bronchoalveolar lavage in 17 patients with histologically-proved sarcoidosis (10 patients, stage I and 7 patients, stage II) and in 4 patients with acute extrinsic hypersensitivity pneumonitis (AEHP). The percentages of cells in the S + (GS + M) phase in the peripheral blood of the patients with sarcoidosis did not differ from those of healthy control subjects. With bronchoalveolar lavage, however, elevated numbers of T cells in the S + (G2 + M) phase were found in the patients with AEHP and in those with stage II sarcoidosis when compared to patients with stage I sarcoidosis. The cellular RNA content of T lymphocytes from the peripheral blood showed a typical bimodal distribution without difference between patients and control subjects. Conversely, T lymphocytes obtained by bronchoalveolar lavage from patients with AEHP and sarcoidosis had a homogeneous low RNA content which differed from that of T lymphocytes from the blood from that of in vitro phytohemagglutinin-stimulated lymphocytes. These findings provide a new approach to the study of the mechanisms of local T-cell activation in sarcoidosis.

Adult↗
PubMed1982

[Indexing protein determinations in bronchoalveolar lavage fluids to a reference substance. Value of alveolar potassium].

It is well known that a reference substance is required to determine accurately the protein content of broncho alveolar lavage but there has been disagreement as to the ideal reference substance. We studied the relative usefulness and reproductibility of potassium and albumin as reference substances in determining protein content in 8 normal subjects and 10 patients with stage 11 sarcoidosis or extrinsic allergic alveolitis. Two successive lavages were performed intentionally using different volumes of injected normal saline. The use of potassium as a reference substance not only permitted a better reproductibility in determination of protein content of sequential broncho-alveolar lavages but also a significantly better discrimination between normal and abnormal subjects.

Albumins↗
PubMed1981

Angiotensin converting enzyme in bronchoalveolar lavage fluid in pulmonary sarcoidosis.

Alveolar angiotensin converting enzyme (ACE) and serum ACE were measured simultaneously in 16 patients with histologically confirmed sarcoidosis and in 16 control subjects. Although alveolar ACE was abnormally elevated in all 15 cases of active sarcoidosis, serum ACE was not. No correlations were found between radiographic staging of pulmonary sarcoidosis and the levels of these enzymes. There was a clear correlation, however, between the levels of alveolar ACE and counts made on bronchoalveolar lavage fluid. This correlation was closer than that existing between serum ACE and bronchoalveolar lavaged lymphocytes. It is suggested that alveolar ACE is an additional biological marker of pulmonary sarcoidosis which is possibly more sensitive than serum ACE.

Adult↗
PubMed1978

[Postprandial variations in serum bile acid levels in humans free of hepatic or intestinal diseases (author's transl)].

The levels of unsulfated, free or conjugated cholic, deoxycholic and chenodeoxycholic acids were measured using gas chromatography in 39 humans free of hepatic or intestinal diseases before and 10, 60, 120 and 180 min after ingestion of a standard meal. The probable maximal levels were determined with an error risk lower than 0.05. In fasting subjects, the observed values are comparable with those obtained by other authors working with gas chromatography or radioimmunoassay. Meal ingestion does not influence in the same way the serum levels of the various bile acids: the chemodeoxycholic serum level rose significantly in all cases whereas cholic and deoxycholic serum levels rose only in two-thirds of observed subjects; 60 and 120 min after the meal for chenodeoxycholic acid, and only 60 min after the meal for cholic acid, the mean values are significantly higher than the fasting ones; 120 min after the meal, the chenodeoxycholic and total bile acid probable maximal levels (respectively 7.4 and 10.3 micrometer) are twice the fasting ones. The cholic to chenodeoxycholic serum level ratio is nearly always lower than 1 but may reach 3. On the basis of these results, the validity and efficacy of the exploration tests based on serum bile acid level determinations are discussed.

Adolescent↗
PubMedDate not supplied

Granulocyte-macrophage colony stimulating factors (GM-CSF) and interleukin 8 (IL-8) production by human bronchial epithelial cells (HBEC) in asthmatics and controls. Lack of in vitro effect of salbutamol compared to sodium nedocromil.

The bronchial epithelium produces cytokines that could contribute to inflammatory events in airways. In this study we determined the basal and TNFalpha stimulated productions of GM-CSF and IL-8 by human bronchial epithelial cells (HBEC) collected from 12 control and six asthmatic patients. Spontaneous and TNFalpha-induced GM-CSF or IL-8 released levels increased significantly with time. Epithelial cells from asthmatic patients spontaneously released high levels of GM-CSF (24 h). TNFalpha potentiated GM-CSF and IL-8 release in control subjects and only the IL-8 production in asthmatics. Nedocromil sodium, an antiinflammatory drug, and salbutamol, a beta2-agonist, are commonly used in asthma. They were evaluated on the spontaneous and TNF-induced expression of GM-CSF and IL-8 in cultured bronchial epithelial cells. Nedocromil sodium, at the concentration of 10(-6) M, reduced the TNF-induced increase in GM-CSF but not the IL-8 release. Salbutamol, at the concentration of 10(-6) or 10(-5) M, did not affect the constitutive or stimulated production of both cytokines.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Increased membrane fluidity in blood leukocytes from allergic subjects. A possible role for leukotriene B4.

Modifications of lipid metabolism and increased plasma membrane fluidity may occur during cell activation and occur in leukocytes of patients with allergic disease. Using a fluorescent probe (TMA-DPH) and a polarization technique, we studied the variations of membrane fluidity in blood leukocytes from allergic and normal subjects. The anisotropic coefficient, which is inversely related to the rotational motion of the probe in membrane phospholipids, was significantly higher in normal subjects than in allergic ones. This result implies an increased membrane fluidity in leukocytes from allergic patients. No correlation could be observed with the etiology or the severity of allergic disease, nor with cell preparation composition or serum IgE level. Such a modification of membrane fluidity has been reproduced after incubation of leukocytes from normal subjects with leukotriene B4, but not with cells from allergic patients. Establishing the mechanism of these differences requires further investigations.

Anisotropy↗