Reproducibility of food atopy patch tests over time in the general child population

Background  The atopy patch test (APT) is no longer an experimental method; it is increasingly being used as a standard diagnostic tool for the characterization of patients with aeroallergen- and food-triggered disorders. Some technical aspects of this test still remain to be answered. We aimed to study the reproducibility of this test over time in the general child population.
Methods  In a general population of 118 children, we investigated the reproducibility of duplicate APTs with four food allergens in their native form, which were repeated at set intervals from the first test: 7 days (group 1), 14 days (group 2), and 21 days (group 3).
Results  We observed very poor reproducibility on both sides of the back in all three studied subgroups. The reproducibility rates and Cohen's κ values did not improve when we did not consider the side of the back. There were no differences in the prevalence of atopy between the subjects with reproducible and nonreproducible APT results. All three groups studied showed no difference in the prevalence rates of atopy. There was no relationship between APT and skin prick test positivity for the same allergen. Questionnaire-derived data about previous food-related reactions did not help in the evaluation of the doubtful nonreproducible APT results with food allergens.
Conclusions  Our results show that the reproducibility of food APTs is poor and unsatisfactory over time, and there is an urgent need for the development of optimal, stable, and good-quality APT testing substances.     

Conformationally constrained congeners of 6-aryl-5-methyl-4,5-dihydro-3(2H)-pyridazinones active on the cardiovascular system: conformational studies by molecular mechanics calculations and 1H NMR spectroscopy

Unsubstituted phenylpyridazinones 1a and 2a and their tricyclic analogues indenopyridazinone 3a, benzocinnolinone 4a, and benzocycloheptapyridazinone 5a were submitted to conformational analysis with Allinger's MM2(85) program in order to better define the relationship between the cardiovascular properties of some derivatives and their preferred conformations. Structures 1-4, giving rise to highly active compounds, were found to exist in a conformation showing a near-planar arrangement of the phenyl and the pyridazinone ring. On the contrary, 5, whose derivatives were inactive, shows two significantly populated conformations both markedly deviated from planarity. 1H NMR analysis of the tricyclic systems 3-5 was in full agreement with the molecular mechanics calculations.     

Dermal alterations in patients with Wilson's disease treated with D-penicillamine

Wilson's disease is characterized by accumulation of copper and D-penicillamine favors its elimination. However, penicillamine binds to precursors of intermolecular crosslinks both in collagen and elastin, and could lead to alterations of these two fibrous proteins. In the present report skin biopsies from patients with Wilson's disease, treated with 900 mg/day of D-penicillamine, for 5, 9, 58 and 60 months, were studied by electron microscopy and compared with findings obtained from skin biopsies of age-matched normal subjects. Clinically, the elasticity and consistency of the skin of Wilson's patients was not modified by D-penicillamine treatment. The ultrastructural organization of collagen fibrils appeared normal in the adults treated with D-penicillamine for 5-9 months. In a 15-year-old girl, treated for 48 months, a high number of collagen fibrils were swollen and unreeved. Elastin fibers were altered in all patients. The alterations were mostly pronounced in the reticular dermis, were proportional to the time of treatment, and consisted of polymorphous aggregates of elastin connected to apparently normal elastin fibers. A stereological analysis, on EM pictures from the patient treated for 60 months, and from an age-matched control, showed a significant decrease in the percentage of collagen and of the mean area occupied by each collagen bundle in the reticular dermis of the patient compared to control; on the contrary, the number of elastin fibers per unit area increased significantly, and the mean area of each elastin fiber decreased. The volume density of elastin was similar to control. The results indicate that prolonged administration of penicillamine to humans induces alterations in the deposition of dermal collagen and elastin.     

GITR/GITRL: more than an effector T cell co-stimulatory system

Glucocorticoid-induced TNFR-related protein (GITR) is a member of the TNFR superfamily, expressed in several cells and tissues including T lymphocytes, NK cells and antigen-presenting cells (APC). GITR activation, upon interaction with its ligand (GITRL), functions as a co-activating signal. GITRL is mainly expressed on APC and GITR/GITRL interaction is important for the development of immune response. This review summarizes recent results about the GITR/GITRL system, focusing on the interplay between APC, effector and regulatory T cells.     

A new member of the tumor necrosis factor/nerve growth factor receptor family inhibits T cell receptor-induced apoptosis

By comparing untreated and dexamethasone-treated murine T cell hybridoma (3DO) cells by the differential display technique, we have cloned a new gene, GITR (glucocorticoid-induced tumor necrosis factor receptor family-related gene) encoding a new member of the tumor necrosis factor/nerve growth factor receptor family. GITR is a 228-amino acids type I transmembrane protein characterized by three cysteine pseudorepeats in the extracellular domain and similar to CD27 and 4-1BB in the intracellular domain. GITR resulted to be expressed in normal T lymphocytes from thymus, spleen, and lymph nodes, although no expression was detected in other nonlymphoid tissues, including brain, kidney, and liver. Furthermore, GITR expression was induced in T lymphocytes upon activation by anti-CD3 mAb, Con A, or phorbol 12-myristate 13-acetate plus Ca-ionophore treatment. The constitutive expression of a transfected GITR gene induced resistance to anti-CD3 mAb-induced apoptosis, whereas antisense GITR mRNA expression lead to increased sensitivity. The protection toward T cell receptor-induced apoptosis was specific, because other apoptotic signals (Fas triggering, dexamethasone treatment, or UV irradiation) were not modulated by GITR transfection. Thus, GITR is a new member of tumor necrosis factor/nerve growth factor receptor family involved in the regulation of T cell receptor-mediated cell death.     

Physical performance in patients with thalassemia before and after transfusion

Patients with thalassemia who are on chronic transfusion programs have chronic ventilatory and cardiocirculatory abnormalities. We studied flow-volume curves, blood gas exchange, and cardiorespiratory responses to exercise in 12 patients with thalassemia major (TM) before and 24 hours after transfusions. Cardiorespiratory fitness was assessed with an exercise tolerance test on a cycle-ergometer. Ten healthy controls underwent the same protocol twice, first at baseline and then 24 hours later, without having had transfusions. We identified two subgroups of patients with a questionnaire: 1) those with no history of airway disease; and 2) those with a history of airway obstruction. Patients with no history of airway disease had normal baseline expiratory flows and no posttransfusion changes; those with a history of airway obstruction had lower pretransfusion expiratory flows rates and significantly decreased posttransfusion forced expiratory volume in 1 second (FEV₁) and forced expiratory flow at 25–75% of forced vital capacity (FEV_25–75%). As a group, TM patients had significantly lower pretransfusion cardiorespiratory function than controls; TM patients' maximum workload was 33% lower, maximum ventilation was 38% lower, maximum oxygen uptake was 25.7% lower, oxygen pulse was 28.6% lower, dyspnea index was 10.6% lower, and ventilatory equivalent for oxygen was 27.1% lower than in control subjects. Although cardiorespiratory responses to exercise improved in both subgroups after transfusion, patients with a history of airways obstruction had a significant posttransfusion increase in their dyspnea index (P = 0.05) and further increased their already abnormally high values of P_ETCO₂ (43 mmHg). These results suggest that the transfusion worsened relative hypoventilation at the maximum workload only in the subgroup with a history of airway obstruction. Pediatr Pulmonol. 1996; 21:367–372. © 1996 Wiley-Liss, Inc.     

Glycoglycerolipid analogues active as anti-tumor-promoters: the influence of the anomeric configuration

The in vitro anti-tumor promoting effect of monohexanoates of 2-O-alpha-D-gluco- and galactopyranosyl-sn-glycerol on the 12-O-tetradecanoylphorbol-13-acetate (TPA) induced Epstein-Barr virus early antigen (EBV-EA) activation was evaluated and compared to the potencies of the corresponding beta-anomers. The results show that the inversion of the anomeric configuration from beta to alpha does not seem to significantly influence the activity, which is present, as for the beta-anomers, even at 1x10 mol ratio without any cytotoxicity.     

Release of transforming growth factor beta-1 in a vestibular schwannoma cell line

Vestibular schwannoma (VS) often displays an irregular growth pattern due to factors which remain unknown. In this study, VS cell lines from tissue removed during surgery were cultured in order to assess the presence of transforming growth factor beta-1 (TGFbeta-1) a multifunctional polypeptide that has different pleiotropic effects on various tissues. The antibody-binding inhibition assay technique was used. The proliferation rate of VS cell lines in vitro was assessed by [3H]thymidine incorporation, with determinations carried out on days 0, 1, 2 and 4 after removal of fetal calf serum (FCS) from the medium. After 48 h of FCS deprivation, cell growth decreased. TGFbeta-1 release also decreased progressively 24 h after removing FCS from the medium, reaching an overall decrease of 50% after 3 days. The cell culturing procedure appeared suitable for VS cells, in that VS cultures were viable for at least 4 months. TGFbeta-1 was initially shown to be released in significant amounts, but also to decrease progressively to values five times lower after 4 days. These data thus support the possibility of a significant association between TGFbeta-1 release and VS cell replication.