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Biomedical subjects

M Laviolette

Publications and source records attributed to M Laviolette.

106 records · Page 6Linked to original sources
PubMed1985

Lymphocyte fluctuation in bronchoalveolar lavage fluid in normal volunteers.

In an attempt to understand the widely varying bronchoalveolar lavage lymphocyte counts reported in normal subjects, we performed bronchoalveolar lavage in 42 healthy nonsmokers. The mean (SD) lymphocyte percentage in this first lavage was 9.6% (7.7%). The values did not fit a normal distribution. Five subjects had more than 20% of lymphocytes, and when they were excluded the distribution of lymphocyte counts was normal. Bronchoalveolar lavage was repeated once or twice in these five subjects 47 days or more after the previous lavage and the lymphocyte count decreased below 14% in four. Eight volunteers with an initial lymphocyte percentage less than 20% also had repeat lavages; two presented a transient increase of lymphocyte count above 20%. These data show that the percentage of lymphocytes in lavage fluid fluctuates significantly in normal subjects and suggest that lymphocyte counts counts higher than 14% should not be considered as normal.

Adult↗
PubMed1985

Absence of correlation between the degree of alveolitis and antibody levels to Micropolysporum faeni.

Specific IgG antibody (Ab) levels to Micropolysporum faeni (MF) antigen were measured in three study groups: 29 farmers of whom one had acute, two chronic and 26 with a past history of Farmer's lung disease (FLD), 91 clinically asymptomatic but exposed farmers and 23 unexposed donors. This study confirms the greater sensitivity of enzyme linked immunosorbent assay (ELISA) over double immunodiffusion (DID): 34 (37%) sera negative by DID were positive by ELISA and only two (4%) were positive by DID and negative by ELISA. Antibody levels to MF were higher in the serum of farmers whether symptomatic (113.2 +/- 196.1 u) or not (25.2 +/- 64.7 u) than in that of unexposed donors (1.05 +/- 1.46 u), (P less than 0.001). In a subgroup of farmers, antibody levels were compared in the serum and bronchoalveolar lavage (BAL) fluid; the levels were higher in the serum than in BAL fluids in all farmers except the only patient with acute FLD. A significant correlation was seen between Ab levels of the serum and BAL fluids. Finally, no correlation was seen between the serum antibody levels and the total number of cells or the percentage of lymphocytes found in BAL fluids, either in the subjects with a history of FLD or the asymptomatic group.

Antibodies, Bacterial↗
PubMed1984

Eosinophil-rich human polymorphonuclear leukocyte preparations characteristically release leukotriene C4 on ionophore A23187 challenge.

Blood samples were obtained from a group of 20 patients with hypereosinophilia (greater than or equal to 1500 eosinophils/mm3). The polymorphonuclear leukocytes (PMNLs) were prepared from blood treated with ethylenediaminetetra-acetic acid by successive dextran sedimentation of the red blood cells, separation of mononuclear leukocytes and PMNLs on Ficoll-Paque, and ammonium chloride treatment of the PMNL fraction. The eosinophil content of the final PMNL preparations ranged from 15% to 75%, as assessed by Wright-stained smears, and the remaining leukocytes were predominantly neutrophils with only 3% to 5% mononuclear cells. The eosinophil-rich PMNL preparations as well as PMNL preparations from normal volunteers were incubated under various conditions and the arachidonic acid metabolites were analyzed by reverse-phase high-performance liquid chromatography. The synthesis of 5-lipoxygenase products was strongly stimulated by the ionophore A23187 in both normal and eosinophil-rich PMNL preparations. Whereas the normal PMNL preparations, which were eosinophil poor, produced 10 to 25 times more leukotriene B4 than leukotriene C4, the eosinophil-rich PMNL preparations characteristically released leukotriene C4 in equal or up to 20 times greater amounts than leukotriene B4.

Arachidonate Lipoxygenases↗
PubMed1984

Abnormal bronchoalveolar lavage in asymptomatic dairy farmers. Study of lymphocytes.

Bronchoalveolar lavage (BAL) was performed on 24 asymptomatic dairy farmers. Thirteen had serum precipitins to Micropolyspora faeni (MF) antigens (Group 1), and 11 were seronegative control subjects (Group 2). All were nonsmokers and had no history of previous lung disease. Thirteen of 24 subjects (9 in Group 1 and 4 in Group 2) had a high percentage of lymphocytes (greater than or equal to 20%) in their BAL. The T-lymphocyte subpopulations as estimated by OKT3, OKT4, and OKT8 monoclonal antibody reactivity were measured in peripheral blood lymphocytes; OKT3 = 58.5 +/- 15.6% for Group 1, and 58.5 +/- 8.7% for Group 2; OKT4 = 40.6 +/- 10.7% and 39.9 +/- 10.0%; OKT8 = 21.5 +/- 10.6% and 22.4 +/- 8.0%, respectively (p = NS). These lymphocyte characteristics were also similar when subjects with a high percentage of lymphocytes in BAL were compared to those with a normal percentage. Specific (MF-coated) chicken erythrocyte lymphocytotoxicity (Group 1, 45.2 +/- 29.5%, Group 2, 49.2 +/- 23.4%), and nonspecific lymphocytotoxicity (Group 1, 43.9 +/- 28.6%, Group 2, 37.9 +/- 18.0%) were also similar. We conclude that a large number of asymptomatic dairy farmers have an increased percentage of lymphocytes in their BAL ("alveolitis") and that peripheral blood lymphocytes in these subjects have normal subpopulations, as assessed by monoclonal antibodies, and normal lymphocytotoxicity.

Adult↗
PubMed1982

Immune reactions in the lungs of asymptomatic dairy farmers.

To test the hypothesis that asymptomatic farmers with serum precipitins to farmers' lung disease antigens also have an immune reaction involving the lungs, we did bronchoalveolar lavage (BAL) in 3 groups of dairy farmers. Group 1: 7 patients with acute farmers' lung disease. Group 2: 10 asymptomatic farmers with serum precipitins to Micropolyspora faeni. Group 3: 9 normal farmers without serum precipitins. Group 1 patients had a large number of cells (90.4 +/- 20 X 10(6)) (mean +/- SEM) with 72 +/- 5.8% lymphocytes in their lavage fluid. Their lavage also had high immunoglobulins A and G/albumin ratios. Six subjects in Group 2 had an increased number of cells (54.1 +/- 14.1 X 10(6)) and a high percentage of lymphocytes (52.5 +/- 6.6%) in their BAL. Two subjects in Group 3 had similar alterations in their lavage fluid: 60.0 and 69.6 X 10(6) cells with 20 and 37.5% lymphocytes, respectively. The other subjects in Groups 2 and 3 had normal lavages. Proliferative responses of BAL lymphocytes to phytohemagglutinin was similar in each group. Circulating immune complexes were increased only in subject with acute farmers' lung disease (Group 1). These results show that some normal farmers have signs of an alveolitis.

Adult↗
PubMed1982

C3b inactivator deficiency with immune complex manifestations.

We report a complete C3b inactivator deficiency in a 28-year-old patient referred for bronchiectasis and recurrent pneumonia. In addition to these recurrent infections, previously described with this deficiency, he also had several immune complex manifestations (rheumatoid factor, circulating immune complexes and one episode of serum sickness). The consequences of C3b inactivator deficiency on complement activation, chemotaxis and opsonization, clearance of immune complexes, and on red blood cell sensitization are discussed. The study of the parents showed an autosomal dominant transmission.

Adult↗
PubMed1981

Human alveolar macrophages: a lesion in arachidonic acid metabolism in cigarette smokers.

Human pulmonary macrophages (PAM) recovered from young cigarette smokers and from age- and sex-matched subjects who had never smoked were used to investigate arachidonic acid metabolism. The uptake of radiolabeled arachidonic acid by PAM obtained from smokers and nonsmokers was not significantly different. The phagocytic indexes of the smoker and nonsmoker macrophages were 17.4 X 3.9% and 18.5 +/- 5.0%, respectively. Both smoker and nonsmoker macrophages produced prostaglandin E2 (PGE2), thromboxane B2 (TXB2) and prostaglandin F2 alpha (PGF2 alpha). A significant decrease in PGE2 and TXB2 synthesis but not in PGF2 alpha synthesis by the smoker PAM compared PAM compared with the nonsmoker PAM was observed using 2 different assays to measure prostaglandin production. Nonsmoker macrophages produced 644 +/- 128,239 +/- 53, and 29 +/- 12 ng/1.5 X 10(6) cells of PGE2, TXB2, and PGF2 alpha, respectively, whereas smoker macrophages synthesized 168 +/- 20, 41 +/- 3, and 17 +/- 1 ng/1.5 X 10(6) cells, as measured by radioimmunoassay. Similar differences were observed using isotopic assays. A cigarette-smoke-induced lesion in phospholipid hydrolysis or the mechanism regulating phospholipid hydrolysis seem most consistent with these findings.

Adult↗
PubMed1980

Intra versus interregional nitrogen gradients in the single breath nitrogen test.

To investigate the genesis of cardiogenic oscillations (C.O.) and the slopes of the single-breath nitrogen test, we studied ten healthy volunteers with a modified test. This test utilized incremental volumes of air from 10% to 100% vital capacity (VC) after a nitrogen washout with oxygen. Subjects exhaled to residual volume, inspired the air volume and completed a full inspiration with oxygen. C.O. and both slopes were positive with low air volumes and negative with a VC of air. The slope of phase IV showed a linear decrease with the increasing inspired air volume, and reached zero with an air volume of 38% VC. AT higher volumes it became progressively more negative. The slope of phase III and C.O. were highly positive with 10% to 50% VC air volume then subsequently decreased. The values for C.O. and the slope of phase III were significantly different (P < 0.001) from those of the slop of phase IV and the apex-base gradients predicted by the model of Milic-Emili et al. These results suggest that intraregional gradients are significantly involved in the genesis of C.O. and the slop of phase III.

Adult↗
PubMedDate not supplied

Airway inflammation and structural changes in airway hyper-responsiveness and asthma: an overview.

Asthma treatment has moved from bronchodilator therapy to an emphasis on anti-inflammatory therapy. Airway inflammation is believed to induce airway hyper-responsiveness (AHR) through the release of mediators that increase the airway response to agonists. However, the exact contribution of airway inflammation in the physiology of airway hyper-responsiveness remains undefined. Structural modifications in airways resulting from inflammation may contribute to the development and persistence of AHR and the development of asthma. This paper reviews some of the main components of airway inflammation and structural changes in asthma, and discusses how these processes may interact to modify airway function and induce respiratory symptoms.

Airway Resistance↗
PubMedDate not supplied

Production of tissue-engineered three-dimensional human bronchial models.

We have reported morphological and functional features of cells isolated from human bronchial biopsies. Both epithelial and fibroblastic cells were isolated from the same biopsies using collagenase. A few models have been established to study normal bronchial response to various agents and to understand the mechanisms responsible for some disorders, such as asthma. We produced three-dimensional bronchial equivalents in culture, using human epithelial and fibroblastic cells. We previously showed that peripheral anchorage can prevent the dramatic collagen contraction in gels seeded with fibroblasts when properly adapted to the size and type of cultured tissues. Our bilayered bronchial constructs were anchored and cultured under submerged conditions and at the air-liquid interface. Three culture media were compared. Serum-free medium supplemented with retinoic acid (5 x 10(-8) M) was found to be the best for maintenance of bronchial cell properties in the reconstructed bronchial tissue. Immunohistological and ultrastructural analyses showed that these equivalents present good structural organization, allowing ciliogenesis to occur in culture. Moreover, human bronchial goblet cells could differentiate and secrete mucus with culture time. Laminin, a major constituent of the basement membrane and basal cells, was also detected at the mesenchymoepithelial interface. Such models will be useful for studying human bronchial properties in vitro.

Bronchi↗