RESUMEN
An adult jenny (5-years-old, non-pregnant) was presented to the Veterinary Teaching Hospital (VTH) of the University of Sassari, with a recent history of appetite loss, extreme underweight condition and reluctance to move. On physical inspection, emaciation [body condition score, BCS: 3/9], muscular waste [muscular condition score, MCS: 1/5], loose/running faeces [faecal score, FS: 2/8], and a general state of mild dehydration were found. Blood analyses outlined a general undernourishment condition [circulating albumins, ALB: 17.6 g/L (21.6-31.6 g/L)] with underlying systemic inflammatory profile and moderate increase in circulating enzymes to explore liver function [aspartate amino-transferase, AST: 657 u/L (279-430 u/L); alanine amino-transferase ALT: 60 u/L (5-14 u/L); gamma-glutamyl-transferase, γ-GT: 87 IU/L (14-69 IU/L); total bilirubin close to the upper limit, TB: 0.20 mg/dL(0.07-0.21 mg/dL)]and hyperlipaemia [TG: 8.70 mmol/L (0.60-2.87 mmol/L)], following fat depots mobilisation, with total cholesterol closed to the lower limit of the physiological range. Hyper-phosphataemia was linked to haemolytic anaemia [P:1.81 mmol/L (0.77-1.39 mmol/L) and red blood cells, RBC: 4.14 1012/L (4.40-7.10 1012)] aligned with the TB to the upper limit. On ultrasound abdominal imaging, enlarged and hyper-echogenic liver was observed. Based on the clinical evaluation, a condition of hepatic lipidosis was diagnosed, requiring dedicated nutritional treatment to solve the extreme emaciation along with the metabolic disorder in support of medical therapy. A two-step feeding protocol was planned to support treatments aiming at immediate re-hydration (Ringer lactate solution 2 ml/kg/8 h). The nutritional objectives were meant at first to restart the voluntary feed intake. Gradual increasing energy provision through a palatable hay-based diet was planned to cover one fourth of daily metabolizable energy requirement calculated on the expected metabolic weight, adjusted according to the daily intake of feed and clinical condition. At the conclusion of this first 7-day phase, circulating blood parameters were closer to the reference values and the BCS moved from 3 to 4 out of 9. Bowel motility was restored, and faecal score improved (4/8). In the second phase, allowance to pasture and a combination diet with compound mixed feed were designed. Within four weeks of starting the nutritional plan, blood parameters were re-established to reference values. The gradual feed provision calculated in this two-phase approach proved successful in support of the overall clinical improvement observed after four weeks of treatment, in a severely undernourished jenny with compromised liver functions.
RESUMEN
Food allergies and food intolerances are clinically difficult to discriminate. Most often, along with cutaneous adverse food reactions or CAFR, they are classified as adverse food reactions, whose causes are numerous, including toxic compounds. Eighteen indoor-housed domestic cats with evident clinical symptoms related to CAFR (drooling, back and neck intense itching, neck eczema, chronic conjunctivitis and stomatitis) involving skin lesions were studied. Cytological evaluations of ear, skin and gingival swabs revealed an increased turnover of keratinocytes while the oxytetracycline ELISA determination showed an unexpected high amount of oxytetracycline in all cats at the first visit. All cats were then randomly assigned to receive a standard (SD group) or a nutraceutical diet (ND group) for 60 days. In the ND group a significant reduction of the mean serum concentration of oxytetracycline, pruritus intensity and skin lesion severity (**p<0.01, ***p<0.001, and ***p<0.001, respectively) was observed after 60 days, and associated with a significant improvement in the clinical picture. Although a direct correlation between oxytetracycline presence within cat sera and CAFR-related symptoms has never been described, this study highlights the benefit of a specific nutraceutical diet supplementation in improving clinical symptoms and skin lesions in cats with CARF.
Asunto(s)
Enfermedades de los Gatos/dietoterapia , Dermatitis/veterinaria , Suplementos Dietéticos , Hipersensibilidad a los Alimentos/veterinaria , Animales , Gatos , Dermatitis/inmunología , Femenino , Masculino , Prurito/dietoterapia , Prurito/veterinariaRESUMEN
The well-being of dogs can be affected by changes in human lifestyle, eating habits and increased stressors that lead to behavioural disorders including fear, hyperactivity and anxiety, followed by negative affective moods and poor welfare. This randomised, controlled clinical evaluation involved 69 dogs, 38 males and 31 females, of different breeds, with behavioural disorders related to anxiety and chronic stress. They were fed a control diet or a nutraceutical diet (ND group) for 45â days. Neuroendocrine (serotonin, dopamine, ß-endorphins, noradrenaline and cortisol) and stress (derivatives of reactive oxygen metabolites (dROMs) and biological antioxidant potential (BAP)) parameters related to behavioural disorders were evaluated at the beginning and end of the study period. Results showed a significant increase in serotonin, dopamine and ß-endorphins plasma concentrations (*P<0.05, *P<0.05 and **P<0.01, respectively) and a significant decrease in noradrenaline and cortisol plasma concentrations in the ND group (*P<0.05). dROMs significantly decreased in the ND group (*P<0.05) while BAP was not affected. This study demonstrated for the first time that a specific diet significantly and positively affected neuroendocrine parameters and dROMs. These results open significant perspectives concerning the use of diet and nutraceuticals in the treatment of behavioural disorders.
Asunto(s)
Dieta/veterinaria , Suplementos Dietéticos , Enfermedades de los Perros/dietoterapia , Trastornos Mentales/veterinaria , Animales , Perros , Femenino , Masculino , Trastornos Mentales/dietoterapia , Sistemas Neurosecretores , Estrés Oxidativo , Resultado del TratamientoRESUMEN
Several concerns have been raised over the health of animals used in equestrian games that have their origins in historical or religious events and are currently held in many countries. This study investigated physiological stress response and health status of horses participating in the Sartiglia, a historical horse tournament held in the city of Oristano, Italy, which is principally based on the attempts of masked horsemen at a gallop to run a sword through a hole in a suspended silver star. Blood samples were collected from 21 horses the day before the tournament (D0), during the tournament (D1), and the day after the tournament (D2). Samples were analyzed for complete blood count and biochemical, hormonal, and oxidative stress assays. Data were analyzed using the mixed effect model with sampling session as one of the fixed effects. On the whole, blood parameters evidenced an optimal health status of horses at D0. Significant dehydration and increase of circulating glucose, enzymes, cortisol, and ß-endorphin were registered at D1 (P < 0.001) with a complete recovery of physiological values just at D2. The reactive oxygen metabolites (d-ROM), from which the prooxidant activity can be evaluated, showed an increase from D0 to D1 and D2. Concentration of biological antioxidant potential, which measured the antioxidant capacity, was characterized by the maximum level registered during the tournament and counteracted the simultaneous increase of d-ROM. It can be hypothesized that the tournament played an important role in causing high levels of oxidant markers not only because of the physical exercise represented by the gallop but also because the emotional stressors. In conclusion, the tournament caused significant changes of most parameters, which rapidly recovered to baseline values within the day after. These data will certainly be useful for a future implementation of tests in equine medicine and for the improvements of knowledge of changes of blood parameters and health of horses in similar tournaments.
Asunto(s)
Antioxidantes/metabolismo , Caballos/sangre , Hidrocortisona/sangre , Especies Reactivas de Oxígeno/sangre , Deportes , betaendorfina/sangre , Bienestar del Animal , Animales , Biomarcadores/sangre , Recuento de Células Sanguíneas , Femenino , Estado de Salud , Caballos/fisiología , Italia , Masculino , Estrés Oxidativo/fisiología , Estrés Fisiológico/fisiologíaRESUMEN
BACKGROUND: The most reliable method to diagnose food allergy or to determine tolerance is the oral food challenge. OBJECTIVES: The aim of this study was to describe the open oral food challenge applied to children with suspicion of cow's milk allergy mediated by immunoglobulin E, and evaluate the relation between the clinical history and skin prick test with the challenge outcomes. PATIENTS AND METHODS: Forty-six children (median age 13.8 months), with clinical history of immediate reactions to cow's milk and positive skin prick test, underwent an open oral food challenge with cow's milk. RESULTS: The challenge was positive in 41.3%. Cutaneous reactions were the most common (73.7%), followed by respiratory (57.9%) and gastrointestinal reactions (36.8%). According to the severity of the reactions, 57.9%, 36.8% and 5.3% had mild, moderate and severe reactions, respectively. Oral antihistamine was sufficient as treatment in all positive cases. A higher frequency of positive skin prick test with total milk and casein was observed in children with positive oral food challenge. There was a significant agreement between the reactions reported by the family history and those observed during the challenge for 68.4% of children with positive results (Kappa = 0.728; p < 0.001). CONCLUSIONS: The method was considered suitable for children up to three years of age, and is safe and easy to perform. There was a significant correlation between the clinical history and the challenge outcomes. A positive skin prick test with total milk and casein was significantly associated with positive challenge results.
Asunto(s)
Inmunoglobulina E/inmunología , Hipersensibilidad a la Leche/diagnóstico , Preescolar , Femenino , Alimentos , Humanos , Lactante , Masculino , Pruebas CutáneasRESUMEN
Bartonella henselae and Bartonella clarridgeiae were isolated in two cats in Sardinia, Italy. Infection by B. clarridgeiae was characterized by fever and submandibular lymph nodes enlargement while B. henselae infection was asymptomatic. This is the first report of B. clarridgeiae in a cat in Italy and the first isolation of B. henselae and B. clarridgeiae in Sardinia.
Asunto(s)
Infecciones por Bartonella/veterinaria , Bartonella/aislamiento & purificación , Enfermedades de los Gatos/microbiología , Animales , Infecciones por Bartonella/diagnóstico , Bartonella henselae/aislamiento & purificación , Enfermedades de los Gatos/diagnóstico , Gatos , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , Reservorios de Enfermedades/veterinaria , Fiebre/microbiología , Fiebre/veterinaria , Italia , Ganglios Linfáticos/microbiología , Ganglios Linfáticos/patología , Reacción en Cadena de la Polimerasa , Pérdida de PesoRESUMEN
Double-blind, placebo-controlled food challenges (DBPCFC) are the gold standard method for diagnosing food allergies. However, due to the difficulty of their performance on routine clinic, there is a need for laboratory tools in order to minimise the frequency of DBPCFC. Atopy patch test (APT) represents a promising manner of diagnosing delayed-type allergic reactions. The APT may identify patients with food allergies with negative specific IgE. However, the clinical relevance of positive APT reactions is still to be proven by standardised outcome definitions.
Asunto(s)
Hipersensibilidad a los Alimentos/diagnóstico , Pruebas del Parche , Alérgenos/inmunología , Hipersensibilidad a los Alimentos/inmunología , HumanosRESUMEN
Malignant mixed Müllerian tumor (MMMT) is a rare neoplasm of the female genital tract. We report a case of bilateral ovarian MMMT in a 10-year-old female dog. Ovaries were only moderately enlarged with a papillary surface and firm nodules. Multiple metastases were observed in the abdominal cavity and pulmonary parenchyma. Histologically, both ovaries had intermingled carcinomatous and sarcomatous components with cartilage and bone. Metastatic lesions were not mixed. The peritoneal metastases were carcinomatous; pulmonary metastases were sarcomatous. Carcinomatous elements of the MMMT were immunohistochemically positive for cytokeratin (CK) AE1/AE3, CK7, and vimentin and estrogen receptors. Conversely, the sarcomatous cells were positive for vimentin, but negative for CKs. Chondrocytes also expressed S-100 protein. On the basis of similarities to human ovarian MMMT, the diagnosis was heterologous malignant mixed Müllerian tumor of the ovary.
Asunto(s)
Enfermedades de los Perros/patología , Tumor Mulleriano Mixto/veterinaria , Neoplasias Ováricas/veterinaria , Animales , Carcinosarcoma/patología , Carcinosarcoma/veterinaria , Perros , Femenino , Tumor Mulleriano Mixto/patología , Neoplasias Ováricas/patología , Neoplasias Peritoneales/secundario , Neoplasias Peritoneales/veterinariaRESUMEN
BACKGROUND: The delineation of allergenic (i.e. IgE-binding) epitopes in cow's milk proteins and the amino acids (AAs) critical for IgE-binding is necessary to understand better the structural properties of an allergen and to develop more efficacious immunotherapeutic reagents. Furthermore, this information may enable us to understand better cross-sensitivity between different allergens. METHODS: Eleven peptides, 10-14 AAs in length, representing the IgE-binding epitopes of kappa-casein were synthesized on a derivatized cellulose membrane with single AA substitutions at each position. Membranes were incubated with pooled sera from 15 milk-allergic patients and individual sera from 10 of the patients included in the pool. RESULTS: For 10/11 allergenic peptides, one to five different single AA substitutions resulted in elimination of IgE-binding of pooled patient sera. Overall at least one mutated peptide could be found for these 10 IgE-binding sites that resulted in a reduction of IgE-binding in at least 80% of the patients who recognized the native protein. Furthermore, the IgE-binding region at AA104-112 on bovine kappa-casein showed a high degree of similarity with the human kappa-casein, respectively, including the AAs critical for IgE-binding. CONCLUSION: This finding suggests that critical AAs should be assessed with both pooled and individual patient sera to account for the B-cell epitope heterogeneity between patients, with cow's milk allergy. In addition, we identified two potentially cross-reactive peptides between bovine and human caseins of unknown clinical relevance.
Asunto(s)
Secuencia de Aminoácidos , Caseínas/química , Análisis Mutacional de ADN , Epítopos/metabolismo , Inmunoglobulina E/metabolismo , Hipersensibilidad a la Leche/etiología , Adolescente , Animales , Caseínas/genética , Caseínas/metabolismo , Niño , Preescolar , Epítopos/química , Epítopos/genética , Humanos , Inmunoglobulina E/sangre , Hipersensibilidad a la Leche/inmunología , Datos de Secuencia Molecular , Péptidos/síntesis química , Péptidos/química , Péptidos/metabolismoAsunto(s)
Angiomatosis Bacilar/veterinaria , Bartonella henselae , Enfermedades de los Gatos/epidemiología , Enfermedades de los Perros/epidemiología , Angiomatosis Bacilar/epidemiología , Animales , Portador Sano , Enfermedades de los Gatos/sangre , Gatos , Enfermedades de los Perros/sangre , Perros , Femenino , Italia/epidemiología , Masculino , Estudios SeroepidemiológicosRESUMEN
In this case report, an atypical clinical presentation of leishmaniosis in a dog with multiple nodular lesions of the tongue is described. Haematological and biochemical analysis, serological test for Leishmania infantum antibodies and biopsy samples from several nodules of the tongue for histopathological examination were made. The final diagnosis of leishmaniosis was based upon the observation of amastigotes in the bioptic samples. It is recommended to consider leishmaniosis among the list of differentials of mucosal nodular lesions, at least in endemic areas.
Asunto(s)
Antiprotozoarios/uso terapéutico , Enfermedades de los Perros/patología , Leishmania infantum/patogenicidad , Leishmaniasis Visceral/veterinaria , Lengua/patología , Animales , Anticuerpos Antiprotozoarios/sangre , Enfermedades de los Perros/tratamiento farmacológico , Perros , Femenino , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/patología , Resultado del TratamientoRESUMEN
BACKGROUND: For immunotherapeutic approaches, 'critical' amino acids (AAs) within allergenic epitopes are replaced with alternate AAs to eliminate IgE antibody binding. OBJECTIVE: To determine the critical AAs for IgE binding in beta-casein and beta-lactoglobulin (BLG). METHODS: Peptides of 10-14 AAs in length were synthesized on a derivatized cellulose membrane with single AA substitutions (alanine or glycine) at each position. Membranes were incubated with a pool of sera from 15 cow's milk-allergic patients and individual sera from six of the 15 patients. In cases where no decrease in binding occurred with a single AA substitution, peptides with two AA substitutions were generated and labelled. RESULTS: Using pooled patient sera, single AA substitutions led to complete elimination of binding to six of 11 peptides for beta-casein and to all six peptides for BLG. Substituting two AAs led to an elimination of binding to four of the remaining five beta-casein epitopes. However, in three of the 11 modified beta-casein peptides and five of the six BLG peptides, no decrease in IgE binding occurred in at least one individual patient. For these patients, critical AAs other than those defined by the patient serum pool were identified, indicating a heterogeneous pattern of IgE recognition. CONCLUSION: These results indicate that AAs critical for IgE binding are more heterogeneous than initially defined by pooled milk-allergic patient sera. For future immunotherapeutic interventions with mutated peptides, critical AAs should also be identified with individual patient sera to account for heterogeneity of IgE binding between patients.
Asunto(s)
Sustitución de Aminoácidos/inmunología , Caseínas/inmunología , Epítopos/inmunología , Inmunoglobulina E/inmunología , Lactoglobulinas/inmunología , Hipersensibilidad a la Leche/inmunología , Leche/inmunología , Adolescente , Animales , Caseínas/genética , Bovinos , Niño , Preescolar , Análisis Mutacional de ADN , Epítopos/genética , Femenino , Variación Genética , Humanos , Inmunoterapia , Lactoglobulinas/genética , Masculino , Leche/efectos adversos , Hipersensibilidad a la Leche/sangre , Hipersensibilidad a la Leche/genética , Hipersensibilidad a la Leche/terapia , Péptidos/genética , Péptidos/inmunologíaRESUMEN
Ehrlichiosis and rickettsiosis are very common, widespread diseases. These diseases are present in Sardinia year round because its temperate weather permits the survival of many kinds of tick vectors. A thousand dogs were subjected to physical, hematological, biochemical examinations and serological tests. All 1,000 sera were analyzed by indirect immunofluorescence antibody test to detect antibodies against E. canis and R. rickettsii. A high seroprevalence (about 50%) was detected for both etiological agents, without differences in relation to sex, breed, or usage. A high seroprevalence, corresponding to 62.5% for ehrlichiosis and 64% for rickettsiosis, was observed in the age group of 13-60 months. The mortality was greatest in the males in the age group, which manifested the disease in the chronic phase.
Asunto(s)
Enfermedades de los Perros/epidemiología , Ehrlichiosis/veterinaria , Infecciones por Rickettsia/veterinaria , Animales , Anticuerpos Antibacterianos/sangre , Enfermedades de los Perros/inmunología , Enfermedades de los Perros/microbiología , Perros , Ehrlichia/crecimiento & desarrollo , Ehrlichia/aislamiento & purificación , Ehrlichiosis/epidemiología , Ehrlichiosis/inmunología , Técnica del Anticuerpo Fluorescente Indirecta , Italia/epidemiología , Prevalencia , Rickettsia/genética , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/epidemiología , Infecciones por Rickettsia/inmunologíaRESUMEN
An N-capping box and a hydrophobic staple motif are strictly conserved in the core of all known glutathione S-transferases (GST). In the present work, mutations of hGSTA1-1 enzyme residues forming these motifs have been generated. The analysis of S154A, D157A, and S154A/D157A capping mutants indicate that the removal of this local signal destabilizes the protein. The fact that the third helical residue D157A mutation (N-3) was much more destabilizing than the first helical residue S154A mutation (N-cap) suggests that the appropriate conformation of the conserved substructure formed by the alpha 6-helix and preceding loop (GST motif II) is crucial for the overall protein stability. The refolding study of GSTA1-1 variants supports the prediction that this subdomain could represent a nucleation site of refolding. The analysis of L153A, I158A, L153G, and L153A/I158A hydrophobic staple mutants indicate that the removal of this motif destabilizes the GSTA1-1 structure as well as its refolding transition state. The hydrophobic staple interaction favors essential inter-domain contacts and, thereby, in contrast to capping interactions, accelerates the enzyme reactivation. Its strict conservation in the GST system supports the suggestion that this local signal could represent an evolutionarily conserved determinant for rapid folding.
Asunto(s)
Secuencia Conservada , Glutatión Transferasa/metabolismo , Secuencias de Aminoácidos , Activación Enzimática , Estabilidad de Enzimas , Glutatión Transferasa/química , Glutatión Transferasa/genética , Humanos , Isoenzimas , Cinética , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Conformación Proteica , Pliegue de ProteínaRESUMEN
Five peptides matching the helices alpha4, alpha5, alpha6, alpha7, and alpha8, spanning the entire sequence of domain II of pG-STP1-1, have been synthesized and their conformations analyzed by far-UV CD spectroscopy. The results show that a5, a7, and a8 peptides are unstructured in water/2,2,2-trifluoroethanol (TFE) solutions. The a4-peptide also adopts random conformations in aqueous solvent. Moreover, the relative low helical content (20%), estimated for this peptide in the presence of 30% (v/v) TFE, suggests that the sequence of this protein fragment does not possess sufficient information for a strong helical propensity. On the contrary, the synthesized a6 peptide, in the presence of TFE, showed a relevant structural autonomy with a helical content (41%) which was significantly higher than that estimated, under the same conditions, for all other peptides. More in general in the presence of solvents less polar than water, the isolated a6 peptide shows the same helical conformation adopted by the corresponding alpha6-helix in the hydrophobic core of the protein. A n-capping box motif, strictly conserved at the N-terminal of the alpha6-helix of all GST and related protein including eucaryotic translation elongation factor (EF1gamma) and the yeast prion protein Ure2, plays an important role in the alpha-helix nucleation and stability of this protein fragment. The results suggest that the alpha6-helix might represent a nucleation site of GST folding and that the helical conformation of this region of the protein is an important requirement during earlier events of GST refolding.
Asunto(s)
Glutatión Transferasa/química , Fragmentos de Péptidos/química , Pliegue de Proteína , Secuencia de Aminoácidos , Dicroismo Circular , Isoenzimas/química , Datos de Secuencia Molecular , Conformación Proteica , Estructura Secundaria de Proteína/efectos de los fármacos , Estructura Terciaria de Proteína , Trifluoroetanol/química , Trifluoroetanol/farmacología , Agua/químicaRESUMEN
The distinction between physiological (apoptotic) and pathological (necrotic) cell deaths reflects mechanistic differences in cellular disintegration and is of functional significance with respect to the outcomes that are triggered by the cell corpses. Mechanistically, apoptotic cells die via an active and ordered pathway; necrotic deaths, conversely, are chaotic and passive. Macrophages and other phagocytic cells recognize and engulf these dead cells. This clearance is believed to reveal an innate immunity, associated with inflammation in cases of pathological but not physiological cell deaths. Using objective and quantitative measures to assess these processes, we find that macrophages bind and engulf native apoptotic and necrotic cells to similar extents and with similar kinetics. However, recognition of these two classes of dying cells occurs via distinct and noncompeting mechanisms. Phosphatidylserine, which is externalized on both apoptotic and necrotic cells, is not a specific ligand for the recognition of either one. The distinct modes of recognition for these different corpses are linked to opposing responses from engulfing macrophages. Necrotic cells, when recognized, enhance proinflammatory responses of activated macrophages, although they are not sufficient to trigger macrophage activation. In marked contrast, apoptotic cells profoundly inhibit phlogistic macrophage responses; this represents a cell-associated, dominant-acting anti-inflammatory signaling activity acquired posttranslationally during the process of physiological cell death.
Asunto(s)
Apoptosis/inmunología , Macrófagos/inmunología , Necrosis , Fosfatidilserinas/inmunología , Animales , Células Cultivadas , Ligandos , Activación de Macrófagos/inmunología , Ratones , Temperatura , Células Tumorales CultivadasRESUMEN
An N-capping box motif (Ser/Thr-Xaa-Xaa-Asp) is strictly conserved at the beginning of helix alpha6 in the core of virtually all glutathione transferases (GST) and GST-related proteins. It has been demonstrated that this local motif is important in determining the alpha-helical propensity of the isolated alpha6-peptide and plays a crucial role in the folding and stability of GSTs. Its removal by site-directed mutagenesis generated temperature-sensitive folding mutants unable to refold at physiological temperature (37 degrees C). In the present work, variants of human GSTP1-1 (S150A and D153A), in which the capping residues have been substituted by alanine, have been generated and purified for structural analysis. Thus, for the first time, temperature-sensitive folding mutants of an enzyme, expressed at a permissive temperature, have been crystallized and their three-dimensional structures determined by X-ray crystallography. The crystal structures of human pi class GST temperature-sensitive mutants provide a basis for understanding the structural origin of the dramatic effects observed on the overall stability of the enzyme at higher temperatures upon single substitution of a capping residue.
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Glutatión Transferasa/química , Mutación/genética , Sustitución de Aminoácidos/genética , Cristalografía por Rayos X , Estabilidad de Enzimas , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Humanos , Modelos Moleculares , Estructura Secundaria de ProteínaRESUMEN
Chronic airways inflammation in chronic obstructive pulmonary disease (COPD) induces the activation of several cell types with delivery of proteases and reactive oxygen species (ROS). Assessing oxidant content in the exhaled air of COPD patients has proven useful in monitoring airway inflammation. The present study was designed to confirm the usefulness of exhaled hydrogen peroxide concentration determination in COPD patients using a new technique which allows longer storage of the expired air condensate before the H2O2 assay. The technique was applied in 13 healthy nonsmoking subjects (six male, age range 22-40 yrs) and in seven patients (five male, age range 58-81 yrs) with mild or moderate COPD. Subjects breathed into a one-valve mouthpiece, and the exhaled air was directed into a vial kept at 0 degree C. After approximately 15 min of quiet breathing, 1 mL of expired air condensate was collected. An aliquot, 450 microL, of this sample was immediately added to an equal volume of a reaction mixture containing 2 mM 3,5,3',5'-tetramethylbenzidine and 40 microL of enzyme stock solution (0.5 mg.mL-1). After 15 min, 45 microL sulphuric acid was added (1 N final concentration), resulting in a reaction mixture pH of 1.0. After a further 10-min incubation, H2O2 concentration determination was performed spectrophotometrically at 450 nm. This solution, as well as the H2O2 assay, was stable for > or = 24 h if the sample was kept in the dark and at 4 degrees C. There was high stability on repeated measures, with a coefficient of variation equal to zero. The mean +/- SD H2O2 level in exhaled air from normal subjects was 0.12 +/- 0.09 microM, whereas it was significantly increased in COPD patients (0.50 +/- 0.11 microM; p = 0.0001 compared to healthy subjects). In three healthy control subjects, a normal H2O2 level in expired air increased to 0.70-0.80 microM during an acute upper respiratory tract infection. This new technique of hydrogen peroxide assay in expired air condensate greatly minimizes the inaccuracy deriving from the instability of hydrogen peroxide. The preliminary results obtained using this technique provide direct evidence for increased reactive oxygen species production in the airways of stable chronic obstructive pulmonary disease patients. However, the specificity of the procedure could be reduced by the interference of upper respiratory tract infections.
Asunto(s)
Pruebas Respiratorias , Peróxido de Hidrógeno/análisis , Enfermedades Pulmonares Obstructivas/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Evaluación como Asunto , Femenino , Humanos , Enfermedades Pulmonares Obstructivas/terapia , Masculino , Persona de Mediana EdadRESUMEN
The acid denaturation of human glutathione transferase P1-1 (hGSTP1-1) has been performed to investigate the unfolding intermediates of the protein and their possible involvement in the refolding mechanism. The acid-induced structures of GSTP1-1 have been characterized by activity, gel filtration, intrinsic fluorescence and far-u.v. circular dichroism (CD) techniques. Because of the non-identity of the different transitions monitored, the acid denaturation of hGSTP1-1 appears to be a multistep process during which several intermediates coexist in equilibrium. The dependence of inactivation on the protein concentration, as well as gel-filtration experiments, indicate that the inactivation transition, centred at about pH 4.0, corresponds to the monomerization of the protein. At pH 2.0, when the enzyme is completely inactive, the protein retains a small, but significant, amount of secondary structure. This means that the dimeric arrangement of the molecule is important for maintaining the native-like secondary structure of the monomer. The results show that, at low pH, the compact state of the GST monomer, even upon the addition of salts, does not possess native-like secondary structure as described for many monomeric proteins (molten globule). In the presence of physiological concentrations of salts, the protein solution at pH 2.0 leads to a dead-end aggregation process, suggesting that this compact state cannot represent a productive intermediate of the refolding pathway.
Asunto(s)
Gutatión-S-Transferasa pi/química , Dicroismo Circular , Ácido Cítrico/farmacología , Gutatión-S-Transferasa pi/efectos de los fármacos , Gutatión-S-Transferasa pi/metabolismo , Humanos , Concentración de Iones de Hidrógeno , Conformación Proteica , Desnaturalización Proteica/efectos de los fármacos , Pliegue de Proteína/efectos de los fármacosRESUMEN
The specific (i, i+5) hydrophobic staple interaction involving a helix residue and a second residue located in the turn preceding the helix is a recurrent motif at the N terminus of alpha-helices. This motif is strictly conserved in the core of all soluble glutathione transferases (GSTs) as well as in other protein structures. Human GSTP1-1 variants mutated in amino acid Ile(149) and Tyr(154) of the hydrophobic staple motif of the alpha6-helix were analyzed. In particular, a double mutant cycle analysis has been performed to evaluate the role of the hydrophobic staple motif in the refolding process. The results show that this local interaction, by restricting the number of conformations of the alpha6-helix relative to the alpha1-helix, favors the formation of essential interdomain interactions and thereby accelerates the folding process. Thus, for the first time it is shown that the hydrophobic staple interaction has a role in the folding process of an intact protein. In P(i) class GSTs, Tyr(154) appears to be of particular structural importance, since it interacts with conserved residues Leu(21), Asp(24), and Gln(25) of the adjacent alpha1-helix which contributes to the active site. Human GSTP1-1 variants L21A and Y154F have also been analyzed in order to distinguish the role of interdomain interactions from that of the hydrophobic staple. The experimental results reported here suggest that the strict conservation of the hydrophobic staple motif reflects an evolutionary pressure for proteins to fold rapidly.