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PubMed1997

Inflammation of small airways in asthma.

This study was designed to examine the inflammatory process in the central and peripheral airways of surgically resected lungs from asthmatic and nonasthmatic subjects. Lung specimens were inflated with cryoprotective, rapidly frozen, and systematically sampled. Cryosections prepared from frozen tissue blocks were fixed in acetone/methanol and immunostained with monoclonal antibodies by using the alkaline phosphatase-anti-alkaline phosphatase technique to detect CD3 (T cells), major basic protein (total eosinophils), EG2 (activated eosinophils), anti-tryptase (mast cells), anti-elastase (neutrophils), and CD68 (macrophages). All airways from patients with asthma demonstrated a significant increase in the numbers of T cells and total and activated eosinophils compared with airways from nonasthmatic subjects (p < 0.001). In the patients with asthma, the numbers of activated eosinophils but not T cells were significantly greater in airways with an internal perimeter less than 2 mm compared with those with an internal perimeter greater than 2 mm (p < 0.05). There were also significantly higher numbers of major basic protein-positive eosinophils, when expressed as a fraction of the alveolar wall tissue, in patients with asthma compared with control subjects (p < 0.05). In asthmatic airways with an internal perimeter of more than 2 mm, there was a greater number of activated eosinophils in the tissue between the epithelium and the smooth muscle compared with the tissue between the smooth muscle layer and lung parenchyma (p < 0.05). In contrast, there was a greater number of total eosinophils in the outer airway layer compared with the inner airway layer (p < 0.05). These results show that there is a similar but more severe inflammatory process present in the peripheral compared with the central airways of patients with asthma, which is consistent with the fact that the smaller airways are a major site of obstruction in asthma.

Adult↗
PubMed1998

Subjective and objective assessments in patients with seasonal allergic rhinitis: effects of therapy with mometasone furoate nasal spray.

BACKGROUND: Efficacy of topical nasal steroid therapy for allergic rhinitis is usually evaluated by patient and clinician assessments of subjective symptom changes in diaries and at clinical interviews. OBJECTIVE: We sought to complement the subjective measures with objective measures of nasal cytology, biochemistry, and function. METHODS: In this double-blind, randomized study patients with seasonal allergic rhinitis (SAR) 12 years of age or older received 200 microg mometasone furoate nasal spray (n = 80) or placebo spray (n = 41) once daily for 2 weeks. Subjective assessments by clinician and patient comprised symptom/sign scores and overall therapeutic response evaluations. Objective measures included nasal cytology, nasal biochemistry, nasal airway resistance (NAR), mucociliary clearance, and olfactory functions. RESULTS: Mometasone furoate produced a significantly greater decrease than placebo in subjective measures of SAR for total symptom score (-46% vs -30%, p < 0.05), total nasal score (-47% vs -30%, p < 0.024), individual nasal symptom scores, and overall therapeutic response. The objective measures of eosinophil, basophil, and neutrophil counts and mucociliary clearance were significantly better in mometasone furoate- than in placebo-treated patients. Similarly, within-treatment statistically significant improvements were produced by mometasone furoate but not by placebo sprays for levels of eosinophilic cationic protein, tryptase and albumin, NAR, and odor identification. Significant positive correlations were found between NAR and nasal stuffiness and between eosinophils, basophils, and neutrophils and both eosinophilic cationic protein and albumin. CONCLUSION: Subjective measures of SAR were significantly improved in the mometasone furoate group by comparison with placebo-treated patients. Objective assessments supported the subjective findings because within-treatment measures were frequently significantly improved after mometasone furoate treatment but not after placebo treatment.

Administration, Intranasal↗
PubMed1998

The effects of monosodium glutamate in adults with asthma who perceive themselves to be monosodium glutamate-intolerant.

BACKGROUND: Many previous clinical studies of food-induced asthma suffer from inadequate baseline or control data. A statistically valid, randomized, double-blind, placebo-controlled, monosodium glutamate (MSG)-challenge protocol was developed for identifying early and late asthmatic reactions in an individual. OBJECTIVE: We sought to determine whether MSG would induce bronchoconstriction in a group of adults with asthma who perceived that they were MSG sensitive. METHODS: Twelve subjects (seven women, mean age 35.3 years) with clinically documented asthma and a perception of MSG-induced asthma were recruited. FEV1 and peak expiratory flow data were obtained for 3 whole control days, as well as time-matched data for 3 separate challenge days (1 gm MSG, 5 gm MSG, and 5 gm lactose [placebo]). Opaque capsule challenges were given as a single dose in the morning after an overnight fast. Subjects complied with an elimination diet throughout the study. Nonspecific bronchial hyperresponsiveness was measured at baseline, after the control days, and at the conclusion of the challenges. Venous blood samples were taken at baseline and on each challenge day to determine soluble inflammatory marker (eosinophil cationic protein and tryptase) activity. RESULTS: No immediate or definite late asthmatic reactions occurred. One subject's FEV1 declined more than 15% on MSG challenge, but 95% confidence limits for the control-day spirometry showed that this decline was within her daily variation, hence the challenge was deemed to be negative. No significant changes in bronchial hyperresponsiveness or soluble inflammatory markers were found. CONCLUSIONS: MSG-induced asthma was not demonstrated in this study. This study highlighted the importance of adequate baseline and control data and indicated that such a rigorous protocol for individual assessment is feasible.

Adult↗
PubMed1999

Eosinophilic airway inflammation in nasal polyposis.

BACKGROUND: Asthma and asymptomatic bronchial hyperresponsiveness (BHR) are frequent findings in patients with nasal polyposis (NP). OBJECTIVE: To elucidate mechanisms responsible for the development of BHR, we initiated a prospective study of bronchial inflammation as assessed by bronchial lavage (BL) and bronchial biopsy specimens in 35 patients with noninfectious NP. METHODS: BHR was determined with methacholine provocation testing. Differential cell count, ECP, and histamine and tryptase levels were determined in BLs. Pathologic examination of bronchial biopsy specimens was performed with May-Grünwald-Giemsa stain to assess the number of lymphocytes. Indirect immunoenzymatic methods were used to identify eosinophils and mast cells. RESULTS: Fourteen patients did not exhibit BHR (group A); 7 patients had asymptomatic BHR (group B); and 14 patients had BHR associated with asthma (group C). Patients of group C tended to have a longer duration of nasal symptoms than those of groups A and B. FEV1 (L) was significantly lower in group C than in groups A and B. The number and percentage of eosinophils were significantly higher in BLs in groups B and C than in group A (P <. 05). Patients of groups B and C had a significantly higher number of eosinophils in bronchial submucosa (14.0 +/- 1.5/mm2 and 19.0 +/- 1. 9/mm2, respectively) than patients of group A (0.1 +/- 0.1/mm2). The number of lymphocytes was also higher in groups B and C than in group A. FEV1 (percent of predicted value) and eosinophil number within bronchial mucosa correlated negatively. CONCLUSION: Our results demonstrate that patients with NP and asymptomatic BHR had an eosinophilic bronchial inflammation similar to that observed in asthmatic patients with NP, whereas patients with NP without BHR do not feature eosinophilic lower airways inflammation. The clinical relevance of these results requires careful follow-up to determine whether eosinophilic inflammation in these patients precedes and is responsible for the development of obvious asthma.

Adult↗
PubMed1999

Immunopathogenesis of human gastrointestinal infection by Anisakis simplex.

BACKGROUND: Anisakis simplex is a parasite of fish, and in the case of human infestation, it should be considered as a possible cause of gastrointestinal disease, especially in countries where raw or undercooked fish is a frequent food. Clinical features of anisakiasis may simulate acute abdominal pain, such as that found in patients with gastric ulcers, appendicitis, and Crohn's disease. Furthermore, many cases of anisakiasis are diagnosed as eosinophilic gastroenteritis, which is a broad term for a specific disease. OBJECTIVE: The purpose of this study was to investigate the immunopathogenesis of human gastrointestinal infestation by A simplex. METHODS: Thirteen intestinal biopsy specimens from patients with anisakiasis were analyzed for the presence of messenger (m)RNA for different cytokines and inflammatory mediators by RT-PCR. Specific IgE, eosinophil cationic protein, eosinophil protein X, and tryptase levels were measured in each patient's serum. Also, cell cultures were set up with lymphocytes from some patients and stimulated in vitro with Anisakis and Ascaris antigens. RESULTS: We performed immunologic phenotyping in 13 patients. All patients underwent biopsy after emergency surgery caused by episodes of acute abdominal pain. In all cases inflammatory infiltrate composed of eosinophils and lymphocytes was found in the intestinal wall. We demonstrated that after infestation, a T(H2)-type immune response occurred. Also, major basic protein, nitric oxide, and eotaxin were found in the tissue, and eosinophil cationic protein and eosinophil protein X levels were elevated in sera. CONCLUSION: These data and in vitro lymphocyte cultures indicate that a T(H2) mechanism plays an important role in the inflammatory infiltrate produced by the anchorage of parasites in the gastrointestinal wall.

Abdominal Pain↗
PubMed1999

Gene expression of the GATA-3 transcription factor is increased in atopic asthma.

BACKGROUND: High expression of IL-5 by T cells in the airways of asthmatic individuals is believed to play a fundamental role in the eosinophilia associated with this disease. Recently, the transcription factor GATA-3 was shown to be critical for IL-5 gene expression in TH2 cells in vitro. OBJECTIVE: Our aim was to examine the expression of GATA-3 mRNA and its colocalization within the airways of asthmatic and nonasthmatic individuals. METHODS: We investigated the association between GATA-3 gene expression, airway inflammatory cells, and IL-5 gene expression in bronchoalveolar lavage fluid and bronchial biopsy specimens from atopic asthmatic subjects (n = 10) and normal control subjects (n = 10). RESULTS: We report that GATA-3 mRNA expression is significantly increased in the airways of asthmatic subjects compared with those of normal control subjects (P <.001). Numbers of cells expressing GATA-3 transcripts correlated significantly with reduced airway caliber (P <.05) and airways hyperresponsiveness (P <.05) in asthmatic subjects. Colocalization studies showed that the majority (approximately 60% to 90%) of GATA-3 mRNA+ cells in asthmatic airways were CD3(+) T cells, with smaller contributions from major basic protein+ eosinophils and tryptase+ mast cells. The density of GATA-3 mRNA+ cells correlated significantly with the numbers of cells expressing IL-5 mRNA (P <.001, r = 0.879 for bronchoalveolar lavage fluid; P <. 05, r = 0.721 for biopsy specimens). Furthermore, double in situ hybridization demonstrated that approximately 76% of GATA-3 mRNA+ cells coexpressed IL-5 mRNA and that 91% of IL-5 mRNA+ cells coexpressed GATA-3 mRNA. CONCLUSION: The results of this study provide the first evidence of increased GATA-3 gene expression in association with IL-5 mRNA+ cells in asthmatic airways. These findings support a causal association between augmented GATA-3 expression and dysregulated IL-5 expression in atopic asthma.

Adult↗
PubMed2002

Detection of c-kit point mutation Asp-816 --> Val in microdissected pooled single mast cells and leukemic cells in a patient with systemic mastocytosis and concomitant chronic myelomonocytic leukemia.

The c-kit mutation Asp-816-->Val is detectable not only in neoplastic mast cells (MCs) in patients with systemic mastocytosis (SM) but also in most associated hematologic non-MC lineage disease (AHNMD). In order to prove a monoclonal disease evolution we investigated DNA of pooled microdissected single cells for the presence of the mutation in a patient with SM and concomitant chronic myelomonocytic leukemia (CMML). LightCycler melting curve analysis and direct sequencing of nested polymerase chain reaction (PCR) products revealed the c-kit mutation in tryptase-positive MC and in leukemic CD15-positive cells in bone marrow infiltrates, but not in colonic epithelial cells, thus, suggesting a monoclonal evolution of SM and concurrent CMML on the basis of a somatic mutation in a common hematologic progenitor.

Aged↗
PubMed2003

Characterization of novel stem cell factor responsive human mast cell lines LAD 1 and 2 established from a patient with mast cell sarcoma/leukemia; activation following aggregation of FcepsilonRI or FcgammaRI.

Two novel stem cell factor (SCF) dependent human mast cell lines, designated LAD 1 and 2, were established from bone marrow aspirates from a patient with mast cell sarcoma/leukemia. LAD 1 and 2 cells have the ultrastructural features of human mast cells, and express FcepsilonRI, CD4, 9, 13, 14, 22, 31, 32, 45, 64, 71, 103, 117, 132, CXCR4 (CD184), CCR5 (CD195); and intracytoplasmic histamine, tryptase and chymase. LAD 1 and 2 do not exhibit activating mutations at codon 816 of c-kit. Both LAD 1 and 2 release beta-hexosaminidase following FcepsilonRI or FcgammaRI aggregation. The availability of these cell lines offers an unparalleled circumstance to examine the biology of human mast cells.

Adult↗
PubMed2003

Randomized, double-masked comparison of olopatadine ophthalmic solution, mometasone furoate monohydrate nasal spray, and fexofenadine hydrochloride tablets using the conjunctival and nasal allergen challenge models.

BACKGROUND: It is presumed that exposure to allergens in the environment occurs through both the eyes and the nose. Allergic rhinoconjunctivitis is typically treated with a nasal spray or systemic antihistamine, neither of which may provide adequate relief of the ocular component of the disease. OBJECTIVE: This study was designed to gain a better understanding of the physiologic interaction between the conjunctival and nasal mucosa and thus help establish a profile for the most effective ocular treatment in patients whose allergies have both an ocular and a nasal component. METHODS: This was a single-center, randomized, double-masked clinical study using the conjunctival allergen challenge (CAC) and nasal allergen challenge (NAC) models. It compared the clinical signs and symptoms induced by CAC and NAC, the effects of drugs administered by 3 different routes, and the movement of fluorescein after instillation into the eye and nose (Jones test), and assessed levels of of inflammatory mediators in tears and nasal secretions. At visit l, subjects previously identified as CAC responders underwent NAC to determine the dose of allergen necessary to elicit a sufficient positive reaction. At visit 2, which took place 1 week later, subjects with a positive reaction at visit 1 were randomized to group A (CAC) or group B (NAC), and underwent challenge to confirm the allergen dose necessary to produce a positive reaction. Subjects who qualified were randomized to receive 1 of 3 treatments: olopatadine 0.1% ophthalmic solution, placebo nasal spray, and placebo tablets; mometasone furoate monohydrate 50-microg nasal spray, placebo topical solution, and placebo tablets; or fexofenadine hydrochloride 180-mg tablets, placebo topical solution, and placebo nasal spray. All study medications were administered according to their approved labeling: drops were administered twice daily in the eyes, and the nasal sprays and tablets were administered once daily. At visit 3, which took place 1 week after visit 2, subjects received study medication and 15 minutes later underwent CAC or NAC as before. The primary efficacy variables were ocular itching, ocular redness, and overall nasal symptoms (sneezing, rhino rrhea/postnasal drip, nasal pruritus, palatal pruritus, and nasal congestion) rated on standard scales. Peak nasal inspiratory flow (PNIF) was measured at each visit, and the Jones test was performed at visits 1 and 3. At baseline and after challenge at visits 2 and 3, tear and nasal lavage samples were collected from a subset of randomly selected subjects for analysis of eosinophil cationic protein and tryptase. RESULTS: Seventy-three subjects (42 women, 31 men; mean age, 45.26 years [range, 21-73 years]) were screened, and all were randomized to treatment. Two subjects did not complete the study. CAC induced clinically significant (>1 unit difference) ocular and nasal signs and symptoms, whereas NAC induced clinically significant nasal signs and symptoms only. In group A, there was a greater reduction in ocular itching with olopatadine compared with mometasone and fexofenadine at 3 minutes (P = 0.003 and P = 0.008, respectively) and 5 minutes (P = 0.007 and P = 0.013) after challenge. Although the difference was not statistically significant, overall relief of conjunctival redness (average of 3 vessel beds) was greatest in the olopatadine group, followed by fexofenadine. In group B, prevention of total nasal symptoms was significantly greater with mometasone compared with fexofenadine at 20 minutes (P = 0.006) and 30 minutes (P = 0.014) after challenge. There were no statistically significant differences between treatment groups in nasal symptom scores at any time point after CAC. There were also no significant differences in PNIF between treatment groups. Fluorescein was present in nasal secretions within 5 minutes of being instilled into the eye; no fluorescein was detected in the eye after instillation into the nose. CONCLUSIONS: In this study, exposure of the nasal mucosa to allergen resulted in allergic rhinitis, and exposure of the ocular the ocular surface to allergen resulted in conjunctivitis with a secondary effect in the nose. These results suggest movement of allergens, their mediators, and antiallergy drugs from the ocular surfaces into the nasal cavity, with no meaningful movement from the nasal cavity to the ocular surface. In this controlled model, both the systemic agent and the nasal spray failed to control ocular symptoms. The topical ophthalmic solution provided the most effective management of allergic ocular signs and symptoms, and the nasal spray was most effective for nasal symptoms. Combined use of a nasal spray and topical ophthalmic solution may provide maximal relief in patients whose allergies have both ocular and nasal components.

Administration, Intranasal↗
PubMed2002

Role of protease-activated receptors in airway function: a target for therapeutic intervention?

Protease-activated receptors (PARs) are G-protein-coupled, seven transmembrane domain receptors that act as cellular enzyme sensors. These receptors are activated by the proteolytic cleavage at the amino terminus, enabling interaction between the newly formed "tethered ligand" and the second extracellular loop of the receptor to confer cellular signalling. PARs can also be activated by small peptides that mimic the tethered ligand. In the respiratory tract, PARs may be regulated by endogenous proteases, such as airway trypsin and mast cell tryptase, as well as exogenous proteases, including inhaled aeroallergens such as those from house dust mite faecal pellets. Immunoreactive PARs have been identified in multiple cell types of the respiratory tract, and PAR activation has been reported to stimulate cellular mitogenesis and to promote tissue inflammation. Activation of PARs concurrently stimulates the release of bronchorelaxant and anti-inflammatory mediators, which may serve to induce cytoprotection and to minimise tissue trauma associated with severe chronic airways inflammation. Furthermore, airway inflammatory responses are associated with increased epithelial PAR expression and elevated concentrations of PAR-activating, and PAR-inactivating, proteases in the extracellular space. On this basis, PARs are likely to play a regulatory role in airway homeostasis, and may participate in respiratory inflammatory disorders, such as asthma and chronic obstructive pulmonary disease. Further studies focussing on the effects of newly developed PAR agonists and antagonists in appropriate models of airway inflammation will permit better insight into the role of PARs in respiratory pathophysiology and their potential as therapeutic targets.

Animals↗
PubMed2003

IL-10, an inflammatory/inhibitory cytokine, but not always.

IL-10 has been previously called cytokine synthesis inhibiting factor, produced mostly by Th2 cells, macrophages and CD8+ cell clones. IL-10 is capable of inhibiting the synthesis of several cytokines from different cells, antigen or mitogen activated. IL-10 exerts its inhibition at the mRNA transcriptional and translational level. In addition, IL-10 is a co-stimulatory cytokine on activated T cells. For example, IL-10 inhibits NK cell activity, the production of Th1 cytokines, cytokines generated by peripheral blood mononuclear cells, and macrophage activity. On the other hand, IL-10 exerts immunostimulatory effects on B cells, cytotoxic T cell development and thymocytes. In mast cells derived from CD4+/CD133+ cells, IL-10 inhibits IL-6 and TNFalpha, and prostaglandin E(1) and E(2) induced by IL-6. Here, we report for the first time that IL-10 fails to inhibit tryptase and IL-6 from human mast cell-1 (HMC-1) and human umbilical cord blood-derived mast cells.

Humans↗
PubMed2000

Angiotensin II generation by mast cell alpha- and beta-chymases.

Mast cells secrete alpha- and beta-chymases. Primate alpha-chymases generate angiotensin (AT) II by selectively hydrolyzing AT I's Phe(8)-His(9) bond. This is distinct from the AT converting enzyme (ACE) pathway. In humans, alpha-chymase is the major non-ACE AT II-generator. In rats, beta-chymases destroy AT II by cleaving at Tyr(4)-Ile(5). Past studies predicted that AT II production versus destruction discriminates alpha- from beta-chymases and that Lys(40) in the substrate-binding pocket determines alpha-chymase Phe(8) specificity. This study examines these hypotheses by comparing AT II generation by human alpha-chymase (containing Lys(40)), dog alpha-chymase (lacking Lys(40)), and mouse mMCP-4 (a beta-chymase lacking Lys(40); orthologous to AT II-destroying rat chymase rMCP-1). The results suggest that human and dog alpha-chymase generate AT II exclusively and with comparable efficiency, although dog chymase contains Ala(40) rather than Lys(40). Furthermore, AT II is the major product generated by degranulation supernatants from cultured dog mast cells, which release tryptases and dipeptidylpeptidase as well as alpha-chymase. In contrast to rMCP-1, mMCP-4 beta-chymase readily generates AT II. Although there is competing AT I hydrolysis at Tyr(4), mMCP-4 does not destroy AT II quickly once it is formed. We conclude (1) that chymases are the dominant AT I-hydrolyzing mast cell peptidases, (2) that residues other than Lys(40) are key determinants of alpha-chymase AT I Phe(8) specificity, (3) that beta-chymases can generate AT II, and (4) that alpha- and beta-chymases are not strictly dichotomous regarding AT I cleavage specificity.

Amino Acid Sequence↗
PubMed2004

Orally administered Polypodium leucotomos extract decreases psoralen-UVA-induced phototoxicity, pigmentation, and damage of human skin.

BACKGROUND: The use of psoralen-UVA (PUVA) in patients of skin phototype I to II is limited by side effects of acute phototoxicity and possible long-term carcinogenesis. OBJECTIVE: We sought to assess oral Polypodium leucotomos (PL) extract in decreasing PUVA-induced phototoxicity of human skin on a clinical and histologic level. METHODS: A total of 10 healthy patients with skin phototypes II to III were exposed to PUVA alone (using 0.6 mg/kg oral 8-methoxypsoralen) and to PUVA with 7.5 mg/kg of oral PL. RESULTS: Clinically, phototoxicity was always lower in PL-treated skin after 48 to 72 hours (P<.005), and pigmentation was also reduced 4 months later. Histologically, PL-treated skin showed a significant numeric reduction of sunburn cells (P=.05), preservation of Langerhans cells (P< or =.01), decrease of tryptase-positive mast cell infiltration (P<.05), and decrease of vasodilation (P< or =.01). No differences were found in Ki-67+ proliferating cells. CONCLUSIONS: PL is an effective chemophotoprotector against PUVA-induced skin phototoxicity and leads to substantial benefits of skin protection against damaging effects of PUVA as evidenced by histology.

Administration, Oral↗
PubMed1999

Ozone effects on the immediate-phase response to allergen in the nasal airways of allergic asthmatic subjects.

Epidemiologic and clinical trials have suggested that exposure to ozone increases airway hyperresponsiveness and inflammatory response to inhaled nasal allergen challenge in allergic asthmatic subjects. Previous studies have demonstrated an increased late-phase response to nasal allergen challenge; however, the early-phase response is unknown. We sought to characterize the early-phase response by measuring mast-cell inflammatory mediators and cellular influx at time points immediately following ozone exposure and subsequent allergen challenge. A cohort of mild, asymptomatic dust mite--sensitive asthmatic subjects was identified. Each subject underwent two separate exposures to both 0.4 ppm ozone and clean air in a randomized manner. Nasal lavage was performed before and after each exposure. Nasal allergen was then administered to a defined clinical end point, followed by nasal lavage. Differential cell counts and mast-cell products were identified in each lavage specimen. The mast-cell mediators tryptase and prostaglandin D2 were analyzed, as was a marker of epithelial cell permeability, albumin. Although allergen produced an increase in early-onset mediator release (mast cell-derived), no enhancement was noted after exposure to ozone. Neutrophil and eosinophil inflammatory mediators were not increased after ozone exposure or enhanced after allergen exposure, although ozone did enhance eosinophilic influx after exposure to allergen. Ozone exposure does not promote early-phase--response mediator release or enhance the response to allergen challenge in the nasal airways of extrinsic asthmatic subjects. Ozone, however, may promote an inflammatory cell influx, which helps induce a more significant late-phase response in this population.

Adolescent↗
PubMed2002

Extracellular peptidases of imaginal discs of Drosophila melanogaster.

The imaginal discs of Drosophila melanogaster give rise to the adult epidermis during metamorphosis. During this developmental period several peptidase genes are expressed in disc cells, but there is a paucity of biochemical information regarding substrate specificity. We have used peptides and peptidyl 7-amino-4-methylcoumarin (AMC) substrates to detect several peptidases either positioned on the surface of wing discs or secreted by the imaginal cells. Using [Leu(5)]enkephalin as a substrate, a captopril sensitive dipeptidyl carboxypeptidase (angiotensin I-converting enzyme) and an amastatin-sensitive aminopeptidase were detected as prominent activities associated with intact discs. The formation of [Leu(5)]enkephalin-derived Phe was attributed to the concerted action of the D. melanogaster angiotensin I-converting enzyme (Ance) and a dipeptidase. The disc Ance also showed endopeptidic activity towards locust tachykinin-1 (LomTK-I) by cleaving the Gly-Val peptide bond, but this enzyme was not the sole endopeptidase activity associated with discs. Complete inhibition of the endopeptidic hydrolysis of the LomTK-1 by a disc homogenate required a combination of captopril and the neprilysin inhibitor, phosphoramidon, providing biochemical evidence for a neprilysin-like peptidase, in addition to Ance, in imaginal discs of D. melanogaster. Peptidyl AMC substrates for furin, prohormone convertase and tryptase provided evidence for trypsin-like serine endopeptidases in addition to the metalloendopeptidases. We conclude that imaginal discs are endowed with a variety of peptidases from different families that together are capable of hydrolyzing a broad range of peptides and proteins. Some of these peptidases might be responsible for the metabolic activation/inactivation of signaling peptides, as well as being involved in the production of dipeptides and free amino acids required for protein synthesis and osmotic balance during adult morphogenesis.

Animals↗
PubMed2001

[Anaphylactoid reactions and late skin reactions to iodinated contrast media: present state of the question--idea development].

PURPOSE: Adverse reactions to iodinated contrast media (ICM) share various mechanisms. Anaphylactoid reactions are among the most serious reactions when they are characterized by the elevation of seric tryptase. Pretreatment with corticosteroids and anti-H1 or the use of non-ionic contrast media do not prevent anaphylaxis. Late skin reactions could be mostly related to delayed hypersensitivity. Previous reactions to contrast media, cardiovascular disorders, beta-blockers, asthma, and atopy are risk factors. Female gender and age increase the severity. CURRENT KNOWLEDGE AND KEY POINTS: Anaphylaxis can be demonstrated by intradermal tests and the identification of specific IgEs. Delayed hypersensitivity is shown by the results of epicutaneous tests and the immunohistology of the skin. FUTURE PROSPECTS AND PROJECTS: Allergologic tests are advised in the case of previous reactions. In case of emergency, gadopentetate dimeglumine can be alternatively used. The other risk factors lead to the combination of pretreatment and use of non-ionic monomeric contrast media. Immediate hypersensitivity to iodinated media might increase in the near future with the use of divalent molecules.

Adrenal Cortex Hormones↗
PubMed1998

Tubulointerstitial mast cell infiltration in glomerulonephritis.

Mast cells are involved in chronic inflammation and tissue fibrosis. To determine whether these cells are also involved in tubulointerstitial injury in glomerulonephritis, we assayed mast cell infiltration in the kidneys of 107 patients with primary or secondary glomerulonephritis. Using a monoclonal antihuman tryptase antibody, we detected mast cells in the renal cortical tubulointerstitium, the periglomerular areas, and the medullary interstitium, but not in glomeruli. Renal cortical tubulointerstitial mast cells, including periglomerular area, were estimated as 0.8+/-1.6 cells/mm2 in minimal change nephrotic syndrome (n=7), 1.5+/-0.7 cells/mm2 in minor glomerular abnormalities without nephrotic syndrome (n=7), 6.5+/-7.7 cells/mm2 in membranous nephropathy(n=10), 12.9+/-15.5 cells/mm2 in lupus nephritis (n=15), 13.4+/-8.3 cells/mm2 in focal segmental glomerular sclerosis (n=6), 18.5+/-21.1 cells/mm2 in ANCA-related nephropathy (n=5), 19.8+/-14.2 cells/mm2 in membranoproliferative glomerulonephritis (n=5), 21.3+/-17.7 cells/mm2 in immunoglobulin A (IgA) nephropathy (n=42), and 33.0+/-33.8 cells/mm2 in diabetic nephropathy (n=10). Except for patients with the rapidly progressive glomerulonephritic syndrome (RPGN), the number of infiltrating mast cells significantly correlated with the serum concentration of creatinine at the time of renal biopsy (r=0.59; P < 0.0001) and with the intensity of tubulointerstitial injury as measured by leukocyte infiltration (r=0.72; P < 0.0001) and fibrosis (r=0.75; P < 0.0001). In contrast, mast cell infiltration did not correlate with urinary protein excretion. In relation to serum creatinine concentration, the number of mast cells was fewer in patients with RPGN than in those with chronic glomerulonephritis. These data suggest that mast cells may contribute to the renal deterioration in glomerulonephritis by inducing chronic tubulointerstitial injury.

Adolescent↗
PubMedDate not supplied

[Viral infection and asthma: immunologic mechanisms].

The role of viral respiratory infections in lactating infants and other children continues to generate controversy. The debate concerns the difference, or the apparent differences, in the natural history of wheezing. Viral infections frequently provoke wheezing episodes in non-asthmatic small children but in the majority of these the wheezing disappears without the child subsequently developing asthma. In some cases, however, the wheezing persists and in others the child has asthma. Both the role of viral infection and the mechanisms by which wheezing can be produced in a previously healthy child or exacerbated in asthmatic children are unknown. Several hypotheses have been put forward to explain the relationship between viral infections and persistent wheezing and asthma: 1. Altered immune response to various allergens, whether producing sensitization to these allergens or inhibiting tolerance response to airborne allergens. The number of such patients is increasing, among them those with bronchiolitis, asthma, positive skin tests and specific IgE antibodies. Although there is no unanimity on the matter, these patients also present elevated IL-4 levels and reduced IFN-gamma levels. 2. Induction of inflammation typical of allergic asthma. This occurs when the virus interacts with T lymphocytes; (the natural response to viral infection is Th0 and Th1 lymphocyte differentiation and release of IFN-gamma, which has antiviral properties. In children infected with respiratory syncytial virus Th2 lymphocyte differentiation is produced, which is characteristic of allergic reactions, to the detriment of Th1); epithelial cells (in these cells active viral infection activates nuclear transcription kappa-beta and nuclear IL-6 factor, producing the release of numerous pro-inflammatory cytokines and chemokines as well as expression of adhesion molecules); eosinophils (inducing variable eosinophilia which, to a certain degree, has predictive value for the persistence of wheezing) and other inflammatory cells such as neutrophils and macrophages. In the same context, during viral respiratory infection, the presence of mediators (leukotrienes, especially LTC4, histamine, prostaglandins and tryptase) are observed in respiratory secretions and a correlation between levels of specific IgE mediators can be observed. 3. Increased allergic inflammation--producing bronchial hyperreactivity, mediator release by the various inflammatory cells and neuropeptides from C-sensitive fibers, and even interfering with nitric oxide bronchodilators. In spite of all of the above, it seems that recurrent wheezing after childhood bronchiolitis is not exclusively the result of viral infection and that other factors also play a role in this disease.

Allergens↗