Role of recombinant parvalbumin Gad c 1 in the diagnosis and prognosis of fish allergy

BACKGROUND: The prevalence of fish allergy has increased in recent years. The parvalbumin Gad c 1 is a major cod allergen that is used as a follow-up marker in patients with fish allergy. OBJECTIVES: To determine the clinical and laboratory characteristics of a population of patients with fish allergy. To analyze the role of the specific IgE (sIgE) of recombinant Gad c 1 (rGad c 1) and skin prick tests (SPTs) in confirming the acquisition of tolerance to fish. METHODS: We performed a retrospective study of patients with fish allergy from July 1, 2005 to December 31, 2016. The population was characterized according to demographic data, species of fish associated with allergic reactions, and symptoms. The SPT wheal diameter and sIgE for fish and rGad c 1 were evaluated before acquisition of tolerance (T0) and afterwards (T1). RESULTS: The study population comprised 81 patients (68% male). Most reactions were triggered by hake (51%), mackerel (30%), and cod (26%). The most frequent manifestations were urticaria/angioedema (72%), gastrointestinal symptoms (35%), and eczema (33%); 42% of patients experienced anaphylaxis. At T0, the average sIgE values were as follows: cod, 32.2 kUA/L; sardine, 18.4 kUA/L; hake, 17.5 kUA/L; salmon, 13.9 kUA/L; tuna, 4.5 kUA/L; and rGad c 1, 22.9 kUA/L. In patients who acquired tolerance to at least 1 fish species (n=60; 74%), the mean value of rGad c 1 at T1 (5.1 kUA/L) was significantly lower than at T0 (16.8 kUA/L) (P=.001). Significant values were also recorded for the average diameter of the SPT wheal and the evaluations at T0 and T1 for hake (9.42 mm/3.79 mm) and salmon (7.8 mm/2.8 mm) (P=.002 and P=.026, respectively). CONCLUSION: The decrease in sIgE to rGad c 1 and the mean wheal diameter of SPT for hake and salmon can be used as markers of prognosis in the acquisition of tolerance by fish-allergic patients

ANTECEDENTES: La prevalencia de alergia al pescado ha aumentado en los últimos años. Gad c 1 es una parvalbúmina y un importante alérgeno del bacalao, utilizado como marcador de seguimiento en pacientes con alergia a pescado. OBJETIVOS: Caracterización clínica y de laboratorio de una población de pacientes con alergia a pescados. Analizar la contribución de la IgE específica (sIgE) a parvalbúmina recombinante (rGad c 1) y las pruebas cutáneas (SPT) para confirmar la aparición de tolerancia al pescado. MÉTODOS: Estudio retrospectivo de pacientes con alergia a pescados, desde julio de 2005 hasta diciembre de 2016. Se recogieron datos demográficos, reacciones alérgicas y síntomas con los pescados; el diámetro total de la SPT y el valor de la IgE a rGad c 1 antes (T0) y después de la adquisición de tolerancia (T1). RESULTADOS: Se evaluaron 81 pacientes (68% hombres). La merluza (51%), caballa (30%) y bacalao (26%) desencadenaron la mayoría de las reacciones. Las manifestaciones más frecuentes fueron urticaria/angioedema (72%), síntomas gastrointestinales (35%) eccema (33%) y el 42% de los pacientes tuvieron anafilaxia. En (T0), los valores medios de sIgE fueron: bacalao (32,2 kUA/L), sardina (18,4 kUA/L), merluza (17,5 kUA/L), salmón (13,9 kUA/L), atún (4,5 kUA/L) y rGad c 1 (22,9 kUA/L). En pacientes que adquirieron tolerancia a al menos una especie de pescado (n= 60; 74%), el valor medio de rGad c 1 en T1 (5,1 kUA/L) fue significativamente más bajo que T0 (16,8 kUA/L) (p= 0,001). Los valores del diámetro medio de la SPT en T0 y T1 para merluza (9,42 mm/3,79 mm) y salmón (7,8 mm/2,8 mm) también fueron significativos p= 0,002 y p= 0,026, respectivamente. CONCLUSIÓN: La disminución de la sIgE a rGad c 1 y el diámetro medio de la SPT para merluza y salmón se pueden utilizar como marcadores de pronóstico en la adquisición de tolerancia de alergia a pescados

Protein-DNA interactions define the mechanistic aspects of circle formation and insertion reactions in IS2 transposition.

BACKGROUND: Transposition in IS3, IS30, IS21 and IS256 insertion sequence (IS) families utilizes an unconventional two-step pathway. A figure-of-eight intermediate in Step I, from asymmetric single-strand cleavage and joining reactions, is converted into a double-stranded minicircle whose junction (the abutted left and right ends) is the substrate for symmetrical transesterification attacks on target DNA in Step II, suggesting intrinsically different synaptic complexes (SC) for each step. Transposases of these ISs bind poorly to cognate DNA and comparative biophysical analyses of SC I and SC II have proven elusive. We have prepared a native, soluble, active, GFP-tagged fusion derivative of the IS2 transposase that creates fully formed complexes with single-end and minicircle junction (MCJ) substrates and used these successfully in hydroxyl radical footprinting experiments. RESULTS: In IS2, Step I reactions are physically and chemically asymmetric; the left imperfect, inverted repeat (IRL), the exclusive recipient end, lacks donor function. In SC I, different protection patterns of the cleavage domains (CDs) of the right imperfect inverted repeat (IRR; extensive in cis) and IRL (selective in trans) at the single active cognate IRR catalytic center (CC) are related to their donor and recipient functions. In SC II, extensive binding of the IRL CD in trans and of the abutted IRR CD in cis at this CC represents the first phase of the complex. An MCJ substrate precleaved at the 3' end of IRR revealed a temporary transition state with the IRL CD disengaged from the protein. We propose that in SC II, sequential 3' cleavages at the bound abutted CDs trigger a conformational change, allowing the IRL CD to complex to its cognate CC, producing the second phase. Corroborating data from enhanced residues and curvature propensity plots suggest that CD to CD interactions in SC I and SC II require IRL to assume a bent structure, to facilitate binding in trans. CONCLUSIONS: Different transpososomes are assembled in each step of the IS2 transposition pathway. Recipient versus donor end functions of the IRL CD in SC I and SC II and the conformational change in SC II that produces the phase needed for symmetrical IRL and IRR donor attacks on target DNA highlight the differences.

Copper and iron interactions with angiotensin-converting enzyme inhibitors. A study by fast-atom bombardment tandem mass spectrometry.

Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd.