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Biomedical subjects

L Paradis

Publications and source records attributed to L Paradis.

18 recordsLinked to original sources
PubMed2001

Rhinosinusitis in severe asthma.

BACKGROUND: Chronic rhinosinusitis is a common comorbidity of asthma. However, sinonasal involvement in severe steroid-dependent asthma is still undefined. OBJECTIVE: The aim of the study was to evaluate chronic rhinosinusitis in 35 patients with severe steroid-dependent asthma by using a clinical score and coronal computed tomography (CT) scanning. METHODS: Thirty-five subjects (16 female subjects) with severe asthma requiring daily doses of oral corticosteroids were compared with 34 patients (19 female patients) with mild-to-moderate asthma. Sinonasal involvement was studied by using clinical and CT scores. Airflow obstruction, therapy requirement, and asthma triggering factors were carefully assessed. RESULTS: The proportion of patients with symptoms of rhinosinusitis was similar in both groups of asthmatic subjects (74% in patients with severe steroid-dependent asthma and 70% in patients with mild-to-moderate asthma). All subjects with steroid-dependent asthma versus 88% of subjects with mild-to-moderate asthma had abnormal CT scan results. The clinical (P <.05) and CT scan (P <.0005) severity scores were higher in the subjects with severe steroid-dependent asthma. In both groups the CT scan scores were correlated to the clinical scores (P <.0001 and P <.006), but only in the mild-to-moderate group were both scores correlated with high significance (P <.002 and P <.0005) to the absolute number of blood eosinophils. CONCLUSION: Frequency of rhinosinusitis in patients with mild-to-moderate or severe steroid-dependent asthma is similar; however, sinonasal involvement, as evaluated by clinical symptoms and CT scan imaging, is significantly greater in the patients with severe steroid-dependent asthma than in those with mild-to-moderate asthma.

Adolescent↗
PubMed2000

Modeling of propagation and echo formation in a multilayered structure

In the aim of simulating the ultrasonic inspection of multilayered structure, we propose a hybrid model, based on transfer matrices and ray tracing formalisms. This approach allows one to predict the response of structures containing defects of finite size such as delaminations or adhesion defect.

Journal Article↗
PubMed1998

Immunotherapy with Fel d 1 peptides decreases IL-4 release by peripheral blood T cells of patients allergic to cats.

BACKGROUND: Cells producing a T(H2)-cytokine profile play an important role in the onset and maintenance of atopic diseases, and therefore specific immunotherapy is aimed to induce a switch to cells producing a T(H1)- or T(H0)-cytokine profile. Recently, a novel form of immunotherapy making use of synthetic peptides from the major cat allergen Fel d 1 has been developed, but its mechanisms of action are unknown. OBJECTIVES: We examined the effects of immunotherapy with Fel d 1 peptides on the response to bronchial provocation tests (PD20FEV1) with a standardized Fel d 1 cat extract on Fel d 1-specific serum IgE and IgG levels and in vitro IL-4 and IFN-gamma production. METHODS: Patients allergic to cats received 6 weekly injections of 7.5 micro(g) (low dose), 75 micro(g) (medium dose), or 750 micro(g) (high dose) of Fel d 1 peptides (25 patients) or a placebo (6 patients). RESULTS: Six weeks after ending immunotherapy, posttreatment PD20FEV1 was not significantly different between the treated and placebo groups. However, in the medium- and high-dose groups there was a significant improvement between baseline and posttreatment days. IL-4 release was significantly reduced in the high dose-treated group (P <.005, Wilcoxon W test), whereas it was unchanged in the low or medium dose- and in the placebo-treated groups. In all groups, IFN-gamma, IgE, and IgG levels remained unchanged. CONCLUSION: There was no correlation between the improvement of PD20FEV1 and the decrease in IL-4 production. These data suggest that peptide immunotherapy may act by shifting the Fel d 1-induced response of PBMCs in vitro from the T(H2)-like to the T(H0)-like phenotype.

Adult↗
PubMed1997

Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. VI. Specific immunotherapy prevents the onset of new sensitizations in children.

BACKGROUND: The natural history of allergic sensitization is complex and poorly understood. A prospective nonrandomized study was carried out in a population of asthmatic children younger than 6 years of age whose only allergic sensitivity was to house dust mites (HDMs). OBJECTIVES: The study was designed to determine whether specific immunotherapy (SIT) with standardized allergen extracts could prevent the development of new sensitizations over a 3-year follow-up survey. METHODS: We studied 22 children monosensitized to HDM who were receiving SIT with standardized allergen extracts and 22 other age-matched control subjects who were monosensitized to HDM. The initial investigation included a full clinical history, skin tests with a panel of standardized allergens, and the measurement of allergen-specific IgE, depending on the results of skin tests. Children were followed up on an annual basis for 3 years, and the development of new sensitizations in each group was recorded. RESULTS: Ten of 22 children monosensitized to HDM who were receiving SIT did not have new sensitivities compared with zero of 22 children in the control group (p = 0.001, chi square test). CONCLUSIONS: This study suggests that SIT in children monosensitized to HDM alters the natural course of allergy in preventing the development of new sensitizations.

Animals↗
PubMed1997

Diffuse pulmonary calcinosis without calcium metabolism abnormalities in a renal transplant recipient.

Eighteen years after an uneventful renal transplantation, the chest radiograph of an asymptomatic 50 year old man showed diffuse bilateral infiltrations, predominately at the right apex. Computed tomography (CT) scan demonstrated a diffuse alveolar pattern, the alveoli being filled with a very dense material, with some tracheal calcifications. Bronchoalveolar lavage fluid analysis was normal, but bronchial and transbronchial biopsies revealed calcium deposits in the bronchial mucosa and in the alveolar septa. The diagnosis of diffuse pulmonary calcinosis was established, despite normal blood calcium, phosphorus and magnesium levels, based upon computed tomography scan and pathological findings at fibreoptic bronchoscopy, without the need for an open lung biopsy.

Biopsy↗
PubMed1996

Long-term oral corticosteroid therapy does not alter the results of immediate-type allergy skin prick tests.

BACKGROUND: Medications can modulate the results of skin prick tests (SPTs). Short-term corticosteroid therapy does not alter IgE-mediated skin tests, but the impact of long-term oral corticosteroid therapy on SPT results is unclear. A prospective study was carried out in patients with steroid-dependent asthma who received oral corticosteroids for a long period to determine whether this treatment reduced skin test reactivity. METHODS: Thirty-three patients with steroid-dependent asthma (median age, 59 years) were compared with 66 patients with asthma who served as a control group, matched for age, sex, and atopic status. SPTs with codeine phosphate and a screening battery of standardized allergen extracts were performed before commencement and after at least 1 year of daily oral prednisone treatment (median duration, 2 years; median daily dose, 20 mg). RESULTS: Fifteen patients with corticosteroid-dependent asthma were allergic before treatment, and their sensitization was not changed by long-term treatment with oral corticosteroids. The median wheal diameters induced by codeine phosphate were similar in both groups. The median wheal diameters induced by allergens, and more specifically, by Dermatophagoides pteronyssinus and D. farinae were similar in both groups and did not change in the steroid group after treatment. CONCLUSIONS: Systemic corticosteroid therapy (prednisone, 10 to 60 mg/day) for 2 or more years does not seem to alter SPT reactivity.

Adult↗
PubMed1996

Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. V. Duration of the efficacy of immunotherapy after its cessation.

Specific immunotherapy (SIT) using a standardized mite extract is effective and safe when administered under optimal conditions. However, the duration of its effectiveness after cessation of treatment remains unknown. Forty asthmatic subjects who had received SIT with a standardized Dermatophagoides pteronyssinus (Der p) extract under the same protocol were studied. All had received SIT for a period of 12-96 months and were not receiving pharmacologic treatment. The FEV1 was within normal range in all patients. After cessation of treatment, patients were followed for up to 3 years at 6-month intervals. The patient was considered to have relapsed when symptoms of asthma and/or rhinitis occurred and/or when pulmonary function tests were impaired. Skin tests with increasing concentrations of Der p were carried out before and at the end of SIT. Forty-five percent of the patients did not relapse. The duration of efficacy of SIT was related to the duration of SIT itself (P < 0.04). Most patients who did not relapse had a decrease in skin test reactivity at the end of SIT, whereas most patients who relapsed did not show any change (P < 0.003). The duration of efficacy of SIT after its cessation depends upon the duration of SIT and may be predicted by the effect of SIT on skin tests.

Adolescent↗
PubMed1996

Effects of systemic corticosteroids on cutaneous histamine secretion and histamine-releasing factor in patients with chronic idiopathic urticaria.

BACKGROUND: Enhanced skin mast cell releasability of histamine, increased production of histamine releasing factor (HRF), and cutaneous inflammatory process are the hallmarks of chronic idiopathic urticaria (CU). Although H1-antihistamines are known to alleviate the symptoms effectively in most cases, systemic corticosteroids (CS) are given in more resistant patients. Their mode of action remains a matter of controversy. OBJECTIVES: In the present study, the effects of a 7-day course of CS or placebo on histamine content and HRF production in non-lesional skin of 19 CU patients were examined. METHODS: Using the skin chamber technique, HRF production and histamine content were assessed in normal-appearing skin of patients with CU over a 2-h observation period. Those two parameters were measured before and after treatment, in a double-blind fashion. RESULTS: No significant changes occurred in any parameters after placebo treatment. In contrast with this, significant decrease of HRF activity was observed after 1 week of oral methylprednisolone while no change was documented for histamine secretion. CONCLUSION: These data suggest that CS therapy improves symptoms of CU in association with a decreased production of HRF in uninvolved skin.

Adult↗
PubMed1984

Preparation of young red cells for transfusion using the Fenwal CS 3000 cell separator.

A pheresis procedure was devised to isolate young red cells by centrifugation using the Fenwal CS 3000 continuous flow cell separator. Young red cell enriched products were collected in a 2.5-3-hour procedure. Large numbers of white cells and platelets were collected with the red cells, but cryopreservation and subsequent washing removed 99% of the contaminating cells. At the completion of all processing a product yielding 70% of the total hemoglobin content of a standard frozen/deglycerolized red cell unit was produced. Autologous radiochromium survival of young red cells, measured in 12 normal donors, showed an average 24-hour recovery of 89.9% with a T50Cr of 40.8 days. In paired autologous studies (N = 4) there was a mean increase of 35% in the observed T50Cr of young red cells as compared to standard frozen red cells.

Blood Preservation↗
PubMedDate not supplied

Clinical trial of young red blood cells prepared by apheresis.

Transfusion of young red blood cells (YRBC) with prolonged survival should result in increased intervals between transfusions and, therefore, decreased transfusion-associated iron loading. A prospective clinical trial comparing YRBC transfusions prepared by apheresis versus washed or frozen red cell transfusions was performed in five children with transfusion-dependent thalassemia. A total of 152 YRBC units, evaluated by reticulocyte enrichment and pyruvate kinase activity, were transfused. While a slightly longer interval between transfusions was observed during the time period of YRBC versus the time period after (30.0 +/- 1.5 days versus 27.9 +/- 1.1 days, respectively, p less than 0.02), there was no associated decrease in mg of iron transfused per kg. The effectiveness of transfused YRBC units was less than predicted by in vitro and in vivo studies.

Adolescent↗