Validation of a new in vitro Sun Protection Factor method to include a wide range of sunscreen product emulsion types.

In 2017, Cosmetics Europe performed a double-blinded ring test of 24 emulsion-type sunscreen products, across 3 in vivo test laboratories and 3 in vitro test laboratories, using a new candidate in vitro SPF test method. Based on the results of this work, an article was published showing how data derived from a new lead candidate method conform to new International Standards (ISO) acceptance criteria for alternative SPF test methods (Any alternative method should consider the matrix effect and if required, specify the matrix applicability of the method; Criterion 1a: Systematic differences between methods should be negligible: 95% of all individual results of an alternative method are within the range of ±2× reproducibility standard deviation of the in vivo method, that is overall bias must be below 0.5× reproducibility standard deviation of the in vivo method; Criterion 1b: Measurement uncertainty of an alternative method should be below the measurement uncertainty of the in vivo method. Candidate method predicted values must fall within the full 'funnel' (SPF 6-50+) limits proposed by Cosmetics Europe (derived from the same minimum test design, that is using the ISO24444 Method to measure at least 24 products across at least 3 laboratories using at least 5 test subjects/laboratory, in a blinded fashion).). Of the 24 sunscreen products tested, the majority of emulsions were of the oil-in-water (O/W) type, whereas only one was water-in-oil (W/O) and there were no products with a mineral-only sun filter system. In order to confirm the scope of this method, therefore, a new study was conducted that included 73 W/O (12 mineral + organic, 44 mineral only and 17 organic only) and 3 O/W mineral-only, emulsion-type sunscreen products (a total of 76 new sunscreen products). When combined with the previous 24 products (tested in 3 different laboratories), this yielded a new data set comprising a total of 100 emulsion-type sunscreen products, with SPF values ranging from 6 to 50+ (with a total of 148 data points). These products were tested using the double-plate in vitro SPF test method and compared with the ISO TC217/WG7 acceptance criteria for alternative SPF test methods. Over 95% of paired in vitro: in vivo SPF values lay within the upper and lower limits of the ISO acceptance criteria funnel, with no bias. This new in vitro SPF test method, therefore, meets the minimum requirements for an alternative SPF test method to ISO24444:2010, for emulsion-type sunscreen products (which make up the majority of marketed sunscreen products).

En 2017, Cosmetics Europe a réalisé un ring test en double aveugle de 24 produits de protection solaire de type émulsion, dans 3 laboratoires de test in vivo et 3 laboratoires de test in vitro, en utilisant une nouvelle méthode de test SPF in vitro. Sur la base des résultats de ces travaux, un article a été publié montrant comment les données dérivées de cette nouvelle méthode sont conformes aux nouveaux critères d'acceptation des normes internationales (ISO) pour les méthodes de test SPF alternatives. Sur les 24 produits de protection solaire testés, la majorité des émulsions étaient du type huile dans l'eau (H / E), tandis qu'un seul était de l'eau dans l'huile (E / H) et il n'y avait aucun produit contenant uniquement des minéraux. Afin de confirmer cette méthode, une nouvelle étude a donc été menée comprenant 73 produits E/ H (12 produits contenant des filtres minéraux + organiques, 44 produits contenant des filtres minéraux uniquement et 17 produits contenant des filtres organiques uniquement) et 3 produits H / E contenant des filtres minéraux uniquement, tous de type émulsion (donc un un total de 76 nouveaux produits de protection solaire). Combiné aux 24 produits précédents (testés dans 3 laboratoires différents), cela a donné un nouvel ensemble de données comprenant un total de 100 produits de protection solaire de type émulsion, avec des valeurs SPF allant de 6 à 50+ (avec un total de 148 points de données) . Ces produits ont été testés à l'aide de la méthode de test SPF in vitro double approche et comparés aux critères d'acceptation de l'ISO TC217 / WG7 pour les méthodes alternatives du SPF in vivo. Plus de 95% des valeurs de SPF appariées in vitro: in vivo se situent dans les limites supérieure et inférieure de l'entonnoir des critères d'acceptation ISO, sans biais. Cette nouvelle méthode de test SPF in vitro, par conséquent, répond aux exigences minimales d'une méthode de test SPF alternative à ISO24444: 2010, pour les produits de protection solaire de type émulsion (qui constituent la majorité des produits de protection solaire commercialisés).

Anti-inflammatory / anti-oxidant activity of ingredients of sunscreen products? Implications for SPF.

OBJECTIVE: The Sun Protection Factor (SPF) of sunscreen products is derived from testing in vivo their ability to prevent erythema ("sunburn"). Recently, certain articles have raised concerns that sunscreen products may actively suppress erythema via anti-inflammatory / anti-oxidant (AI/AO) activity. These articles reason that this may result in a higher labelled SPF value than that provided by the efficacy of the UVR filters alone, giving consumers a "false sense of security". On the other hand, since inflammatory processes are known to play a role in the mechanisms of photodamage / skin cancer induction and propagation, AI/AO activity may provide valuable incremental photoprotective benefit (provided that there is no interference with visible erythema). The objective of these studies, therefore, was to investigate the potential of AI/AO ingredients to suppress UVR-induced erythemal response in human skin, in vivo. METHODS: In vivo studies with SPF30 sunscreen formulations containing a variety of AI/AO ingredients were performed according to the International Standard ISO24444:2010 method. While ISO24444:2010 requires assessment of erythema at 20 ± 4h post-irradiation, an additional assessment at 5 h post-irradiation was also used to determine potential delay in erythema development. RESULTS: None of the formulations, containing a variety of AI/AO ingredients, influenced SPF determination in comparison to the vehicle formulation. CONCLUSION: Our in vivo results demonstrate that commonly-used AI/AO ingredients, at concentrations typically used in sunscreen products, neither influence SPF value nor delay erythemal response, i.e., the measured SPF reflects the true photoprotective capacity of the product.

OBJECTIF: Le facteur de protection solaire (SPF) des produits de protection solaire est dérivé de tests in vivo servant à déterminer leur capacité à prévenir un érythème (« coup de soleil ¼). Récemment, certains articles ont soulevé des inquiétudes en insinuant que les produits de protection solaire pourraient activement faire disparaître un érythème par le biais d'une activité anti-inflammatoire/anti-oxydante (AI/AO). Ces articles soutiennent que cela pourrait impliquer une valeur déclarée du SPF plus élevée que celle fournie par l'efficacité des filtres RUV à eux seuls, donnant ainsi une « fausse impression de sécurité ¼ aux consommateurs. D'autre part, étant donné que les processus inflammatoires sont réputés jouer un rôle dans les mécanismes de photo-altération/d'induction et de propagation du cancer de la peau, l'activité AI/AO pourrait apporter un précieux bénéfice photo-protecteur amplifié (à condition qu'il n'y ait aucune interférence avec un érythème visible). L'objectif de ces études était, par conséquent, d'étudier le potentiel des ingrédients contribuant à l'activité AI/AO à faire disparaître la réponse érythémateuse induite par les RUV dans la peau humaine, in vivo. MÉTHODES: Des études in vivo avec des formules de produits solaires à SPF30 contenant une variété d'ingrédients contribuant à l'activité AI/AO ont été effectuées conformément à la méthode correspondant à la norme internationale ISO24444:2010. Bien que l'ISO24444:2010 nécessite l'évaluation de l'érythème à 20 _ 4 heures post-irradiation, une évaluation supplémentaire à 5 heures post-irradiation a également été utilisée pour déterminer l'éventuel délai d'apparition d'un érythème. RÉSULTATS: Aucune des formules, contenant une variété d'ingrédients contribuant à l'activité AI/AO, n'a influencé la détermination du SPF par comparaison à la formule véhicule. CONCLUSION: Nos résultats in vivo démontrent que les ingrédients contribuant à l'activité AI/AO fréquemment utilisés, aux concentrations généralement utilisées dans les produits de protection solaire, n'influencent pas la valeur du SPF, pas plus qu'ils ne retardent la réponse érythémateuse, autrement dit, le SPF mesuré reflète la véritable capacité photo-protectrice du produit.

Validation of an in vitro sun protection factor (SPF) method in blinded ring-testing.

OBJECTIVE: The objective of this work was to investigate the utility of a new in vitro SPF test method in blinded ring-testing, against new ISO acceptance criteria. METHODS: Twenty four blinded, commercial, emulsion-type, primary sunscreen products, covering the full range of labelled SPF in Europe (SPF6 - 50+), were tested by three test institutes using the current ISO24444:2010 In Vivo SPF Test Method and simultaneously by three separate test laboratories using a new candidate in vitro SPF test method, developed under the leadership of Cosmetics Europe (CE). The resulting relationship between in vitro SPF and in vivo SPF values was then compared with acceptance criteria developed recently by the International Standards (ISO) TC217/WG7 Sun Protection Test Methods Working Group. RESULTS: Analysis of the mean inter-laboratory in vitro and mean inter-institute in vivo SPF values revealed a strong correlation between in vitro and in vivo values, with a Pearson correlation coefficient of r2  = 0.88 (P < 0.0001), a slope of 1.01 and a non-significant intercept (-1.48; P = 0.62). When these data were compared to the new ISO WG7 acceptance criteria, method bias was found to be extremely low and over 95% of the coupled data lay within the model 'funnel' (defined by upper and lower confidence intervals). CONCLUSION: In conclusion, the results of blinded ring testing and comparison to new ISO WG7 acceptance criteria indicate that a new in vitro SPF test method meets (and exceeds) these minimum criteria and is an interesting candidate for possible deployment as an industry test methodology.

Inter- and intra-patient variability in breakthrough pain episodes of opioid-treated patients with underlying chronic pain. An observational, prospective and multicenter study / Variabilidad inter- e intra-individual en pacientes con dolor irruptor tratados con opioides. Estudio observacional, prospectivo y multicéntrico

Objective: Since, to date, there are few epidemiological data assessing the diversity in the characteristics of breakthrough pain episodes, the present study was performed to assess the intra-individual variability in the episodes of breakthrough pain in patients with underlying chronic pain controlled with opioids. Methods: An observational, prospective and multicenter study (CADI study) was conducted in the context of the routine clinical practice of Spanish pain specialists recruiting opioidtreated patients with underlying chronic pain. Data were recorded in three visits (baseline, at 7 and 28 days post-inclusion) and by the patient on a patient´s diary card, specifically designed to characterise the first 8 breakthrough pain episodes (type, intensity –using 100 mm Visual Analog Scale– and duration of pain), to assess the intra-individual and inter-individual variability in the intensity, duration and typology of episodes of breakthrough pain. Results: 50 opioid-treated patients were recruited (23 with oncologic pain and 27 with non oncologic pain, mean age of 61.1 years, 62 % females). For all three parameters, inter-patient variability was higher than intra-patient variability throughout the episodes. Nevertheless, we found intra-patient variability in maximum pain intensity, pain intensity at the end of the episode, pain relief and duration of the episode. Conclusions: This is the first study to quantify the intrapatient variability of breakthrough pain. The results show a great variability in terms of intensity and duration of the episode and its typology. Although inter-patient variability is higher, the intra-patient variability is important enough to be taken into account in optimizing the approach and treatment selection (AU)

Objetivos: Debido a los pocos datos epidemiológicos existentes que evalúen la diversidad de las características de los episodios de dolor irruptivo, se realizó el presente estudio, cuyo principal objetivo fue evaluar la variabilidad intraindividual de las crisis de dolor irruptivo en pacientes con dolor crónico controlado con opioides. Métodos: Este estudio observacional, prospectivo y multicéntrico (estudio CADI) se llevó a cabo en el contexto de la práctica clínica habitual, en Unidades del Dolor de España, con la participación de pacientes tratados con opioides para el dolor crónico. Los datos fueron registrados en tres visitas (basal, a los 7 y 28 días después de la inclusión) y por el propio paciente, en un Diario del Paciente, específicamente diseñado para caracterizar los primeros 8 episodios de dolor irruptivo (tipo, intensidad −utilizando la Escala Analógica Visual (EVA)− y duración del dolor) con el objetivo de evaluar la variabilidad intraindividual e interindividual en la intensidad, duración y tipología de los episodios de dolor irruptivo. Resultados: Se reclutaron 50 pacientes, 23 con dolor oncológico y 27 con el dolor no oncológico (edad media de 61,1 años; 62 % de mujeres). Aunque para los tres parámetros medidos, la variabilidad entre pacientes fue mayor que la variabilidad intrapaciente, la variabilidad intraindividual fue significativa en la evaluación de la máxima intensidad del dolor, la intensidad del dolor al final del episodio, el alivio del dolor y la duración del episodio de dolor irruptivo. Conclusiones: Este es el primer estudio que cuantifica la variabilidad intraindividual del dolor irruptivo. Los resultados muestran una gran variabilidad en cuanto a la intensidad y la duración del episodio y su tipología. Aunque la variabilidad entre pacientes es mayor, la variabilidad intrapaciente es lo suficientemente importante como para ser tenida en cuenta para la mejor aproximación y selección del tratamiento (AU)

Características de los pacientes en espera de trasplante renal / Characteristics of patients waiting for kidney transplantation

Los pacientes con insuficiencia renal crónica presentan un marcado descenso de la tasa de filtración glomerular por lo que requieren de terapia de reemplazo renal como la diálisis o el trasplante para sobrevivir. El objetivo del estudio fue determinar las características de los pacientes en lista de espera para trasplante renal. Analizamos 156 pacientes provenientes de diversos centros de diálisis que acudieron al Laboratorio Central de Salud Pública entre julio de 2.013 y agosto de 2.014. Se recolectaron datos demográficos y muestras de sangre para determinar la presencia de anticuerpos anti-HLA por ELISA. Las edades estaban comprendidas entre 4 y 74 años, con un promedio de 40 años. Se registraron pacientes de 15 de las 18 Regiones Sanitarias del país, 50% de los cuales provenían de Asunción y del Departamento Central. La cobertura médica se encontró dividida en partes iguales entre el Ministerio de Salud Pública y el Instituto de Previsión Social. El tiempo promedio en diálisis fue de 34 meses, el 66% de los pacientes fueron poli-transfundidos, el 13% candidatos a retrasplante y el 34% de las mujeres fueron multíparas. El 36% de la población estudiada presentó anticuerpos anti-HLA. Se concluye que los pacientes en espera de trasplante renal se caracterizan por encontrarse en plena edad productiva y por permanecer en diálisis durante varios años. Además, un tercio de esta población se encuentra inmunizada frente a antígenos de histocompatibilidad, lo que dificulta su acceso al trasplante.

Patients with chronic renal failure present a pronounced reduction of the glomerularfiltration rate and therefore, require renal replacement therapy such as dialysis or kidneytransplantation to survive. The aim of this study was to determine the characteristics ofpatients on the waiting list for kidney transplantation. We analyzed 156 patients fromvarious dialysis centers who came to the Central Laboratory of Public Health betweenJuly, 2013 and August, 2014. Demographic information and blood samples were collectedto determine the presence of anti-HLA antibodies by ELISA. Ages were between 4 and 74years, with a mean of 40 years. There were patients from 15 of the 18 health regions ofthe country, 50% of them came from Asunción and the Central Department. Medicalcoverage was found to be divided in equal parts between the Ministry of Public Health andthe Social Security Institute. The mean time on dialysis was 34 months, 66% of thepatients had received multiple blood transfusions, 13% of them were candidates for asecond transplant, and 34% of the women were multiparous. Thirty six percent of thestudied population presented anti-HLA antibodies. The results of this study indicate thatpatients awaiting kidney transplantation in Paraguay are characterized by being at theirproductive age and remain on dialysis for several years. In addition, a third of this population is immunized against histocompatibility antigens, which hinders their access totransplantation.

[Analysis of psychological factors influencing peritoneal dialysis selection]. / Análisis de la influencia de los factores psicológicos en la elección de diálisis peritoneal.

BACKGROUND: Peritoneal dialysis (PD) is not frequently used in our setting. OBJECTIVE: To analyze the psychological factors involved in the choice of renal replacement therapy (RRT). MATERIAL AND METHODS: A prospective observational study of stable patients without cognitive or sensory deficits who were informed about RRT from January 2004 to July 2006 and agreed to participate. The patients were given and completed the Beck Depression Inventory and the Eysenck personality questionnaire. Clinical and sociodemographic data and RRT choice were recorded. End of follow-up: 2007/10/31. RESULTS: 44 patients were studied: age, 65.4 +/- 13.1 years, 48% male, 34% diabetic. When choosing RRT, 36% of patients had symptoms of depression. Neither depression symptoms nor personality traits were related to the choice of dialysis type. The youngest patients chose PD (41%). After a mean followup of 8 +/- 8 months, 70% of patients started RRT (68% haemodialysis [HD], 32% PD). None of the patients who chose HD changed their mind, but 3 of the 13 patients (23%) who chose PD finally commenced HD, usually in the context of a worsening of the disease. Half of the patients with depression symptoms when choosing PD and a third of the patients with higher levels of neuroticism changed their decision and finally opted for HD. CONCLUSIONS: When choosing RRT, the prevalence of depression symptoms is high. Neither depression nor personality traits influenced the initial choice of RRT, although these factors may be involved in subsequent changes to the decision.

Análisis de la influencia de los factores psicológicos en la elección de diálisis peritoneal / Analysis of psychological factors influencing peritoneal dialysis selection

Antecedentes: La diálisis peritoneal (DP) se utiliza poco en nuestro medio. Objetivo: Analizar los factores psicológicos implicados en la elección del tratamiento sustitutivo renal (TSR).Material y métodos: Estudio observacional prospectivo de los enfermos estables y sin déficit cognitivo o sensorial que recibieron información del TSR entre enero de 2004 y julio de 2006y que aceptaron participar. Se les entregaron para su cumplimentación el inventario de depresión de Beck y el cuestionario de personalidad de Eysenck, y se recogieron datos sociodemográficos, clínicos y el TSR elegido. El final del seguimiento fue el 31 de octubre de 2007. Resultados: Se estudiaron 44 pacientes: edad, 65,4 ± 13,1 años; 48% hombres; 34% diabéticos. Un36% tenían síntomas depresivos. Ni éstos ni los rasgos de personalidad se relacionaron con la elección de la técnica. Eligieron DP (41%) los enfermos más jóvenes. Un 70% de los enfermos iniciaron TSR (68% hemodiálisis [HD], 32% DP) a los 8 ± 8 meses. Ninguno de los pacientes que eligieron HD cambió de opinión, pero tres de los 13 pacientes (23%) que habían elegido DP realizaron finalmente HD, en general en el contexto de agudizaciones . La mitad de los pacientes con síntomas depresivos y un tercio de los pacientes con mayores niveles de neuroticismo cambiaron su decisión inicial y optaron finalmente por la HD. Conclusiones: La prevalencia de síntomas depresivos en el momento de elegir TSR es elevada. Ni los síntomas depresivos ni los rasgos de personalidad influyeron en el TSR inicialmente elegido, aunque pueden ser factores implicados en los cambios de decisión posteriores(AU)

Background: Peritoneal dialysis (PD) is not frequently used in our setting. Objective: To analyze the psychological factors involved in the choice of renal replacement therapy (RRT).Material and methods: Prospective observational study of stable patients without cognitive or sensory deficits, who were informed about RRT from January 2004 to July 2006, and agreed to participate. The Beck Depression Inventory and the Eysenck personality questionnaire were administered. Clinical and sociodemographic data, and RRT choice were recorded. End of follow-up: 2007/10/31. Results: We studied 44 patients: age, 65.4 ± 13.1 years, 48% male, 34% diabetic. When choosing RRT, 36% of patients had depressive symptoms. Neither depressive symptoms nor personality traits were related to the choice of the dialysis type. Patients who chose PD (41%) were younger. After a mean follow-up of 8 ± 8 months, 70% of patients started RRT (68% hemodialysis [HD], 32% PD). None of the patients who chose HD changed their mind, but 3 of the 13 patients (23%) who chose PD finally commenced HD, usually in the context of disease exacerbations. Half of the patients with depressive symptoms when choosing PD, and at hird of the patients with higher levels of neuroticism changed their decision and finally opted for HD. Conclusions: When choosing RRT, the prevalence of depressive symptoms is high. Neither depression nor personality traits influenced the initial choice of RRT, but these factors may be involved in subsequent changes of the initial choice (AU)

Implication of the tetraspanin CD9 in the immune system and cancer

Las tetraspaninas son moléculas de la superficie celular de ampliadistribución en los organismos eucarióticos. Poseen como característicaestructural peculiar cuatro dominios transmembranales, regionesN- y C-terminales intracitoplásmicas, y dos lazos extracelularesde distinto tamaño. También poseen un motivo de secuencia CCGen el lazo extracelular mayor, así como residuos polares conservadosen los dominios transmembranales. Las células sanguíneas delos mamíferos expresan combinaciones peculiares de distintas tetraspaninas,incluyendo los antígenos de diferenciación CD9, CD37,CD53, CD81/TAPA-1, CD82, CD151/PETA-3 y CD231/TALLA1.En este trabajo se resumen la estructura y las interacciones desus regiones citoplásmicas con proteínas del citoesqueleto y señalizadoras,como la proteína cinasa C (PKC) o la Fosfatidil-Inositol 4-cinasa (PI4-K). Sus interacciones específicas con otras tetraspaninas,con integrinas, antígenos de histocompatibilidad, y miembros dela superfamilia de las inmunoglobulinas son también revisadas.Las tetraspaninas son proteínas “adaptadoras” o “facilitadoras”.Al formar parte de complejos moleculares, modulan funcionescelulares clave que incluyen la fusión celular, la adhesión, lamigración, la diferenciación y la transducción de señales. Las tetraspaninasse organizan en una red con distintos niveles de asociación,determinados por su resistencia a la solubilización por detergentes.En concreto, se analizan las tetraspaninas como reguladorasdel Sistema Inmunitario gracias a sus interacciones con los receptoresde antígeno de los linfocitos T y B, las moléculas de histocompatibilidadde clase I y clase II, y los co-receptores CD2, CD4,CD5, CD8 y CD19. Por último, se revisa detalladamente el papelde la tetraspanina CD9 en la función de las células linfoides y mieloides,su relevancia en infecciones como el HIV, y la importanciade su asociación con integrinas en la progresión cancerosa

Tetraspanins are cell surface proteins widely distributed ineukaryotic organisms. They characteristically span four times theplasma membrane, have intracellular N and C terminal regions,and two extracellular loops of unequal size. Tetraspanins also possessa CCG motif in the large extracellular loop, and conservedpolar residues in the transmembrane domains. Mammalian bloodcells express different sets of tetraspanins including the differentiationantigens CD9, CD37, CD53, CD81/TAPA-1, CD82,CD151/PETA-3 and CD231/TALLA1.Here, tetraspanin structure and their cytoplasmic tail interactionswith cytoskeletal and signalling proteins like Protein kinaseC (PKC) or Phosphatidyl Inositol 4-kinase (PI4-K) are brieflysummarized. The specific interactions with other cell surface proteins,forming complexes with other tetraspanins and membersof the integrin family, MHC histocompatibility antigens, or membersof the immunoglobulin superfamily are also reviewed.Tetraspanins are considered as “adapter” or “facilitating” proteinsand, through their participation in complexes, they modulatekey cellular functions like cell fusion, adhesion, migration,differentiation and signal transduction. The organization of thetetraspanin web, based on different association levels determinedby their resistance to detergent solubilization, is described. In particular,tetraspanins participating in the regulation of the ImmuneSystem through interactions with the B- and T-cell receptors,the class I and class II MHC antigens, and co-receptors such asCD2, CD4, CD5, CD8, or CD19 are analyzed. At last, the role ofCD9 in myeloid and lymphoid cell function, its relevance to HIVinfection, and the importance of tetraspanin association with integrinsto cancer progression are described in detail

Estudio detallado de las causas de transferencia de Diálisis Peritoneal a hemodiálisis en un Servicio de Nefrología / A detailed study of the causes of tranference from peritonal dialysis to hemodialysis in a nephrology service

Objetivo: Analizar las causas y los factores de riesgo de transferencia a HD de un programa de DP. Material y métodos: Estudio retrospectivo y descriptivo. La DP se ofrece en un plano de igualdad a todos los enfermos con IRCT. Se han recogido variables demográficas, clínicas, existencia de deficiencias físicas, autonomía funcional, peritonitis, tiempo de seguimiento y motivo de finalización de la técnica; causa de transferencia inmediata a hemodiálisis, clasificándolas en potencialmente solucionables o no. De los enfermos transferidos se analizaron: datos clínicos, estado funcional y datos sociales. Resultados: De un total de 103 pacientes, un 58,25 por ciento varones, con una edad media al inicio de la DP de 59 ñ 18, se han transferido a HD un 29 por ciento, se han trasplantado un 16,5 por ciento y fallecieron el 29 por ciento, mientras que 26 enfermos siguen en programa. Las causas inmediatas del paso a HD fueron: fallo de ultrafiltración (UF) y/o infradiálisis 30 por ciento, peritonitis 17 por ciento, problemas relacionados con el catéter o la pared abdominal 17 por ciento, intolerancia a la DP 17 por ciento, problema social y/o enfermedad grave 13 por ciento y deseo del paciente 6 por ciento. Del total de transferencias, el 46,7 por ciento eran por problemas relacionados con la DP no solucionables. Los pacientes transferidos tuvieron más peritonitis que el resto y una mayor proporción de deficiencias físicas que dificultaban realizar la DP. Se observó una gran influencia de los factores personales y sociales en la supervivencia de la técnica de DP (AU)

Rho and Rho-associated kinase modulate the tyrosine kinase PYK2 in T-cells through regulation of the activity of the integrin LFA-1.

We have examined the role of the small GTPase Rho and its downstream effector, the Rho-associated kinase (ROCK), in the control of the adhesive and signaling function of the lymphocyte function-associated antigen-1 (LFA-1) integrin in human T-lymphocytes. Inhibition of Rho (either by treatment with C3-exoenzyme or transfection with a dominant-negative form of Rho (N19Rho)) or ROCK (by treatment with Y-27632) results in the following: (a) partial disorganization and aggregation of cortical filamentous actin (F-actin); (b) induction of LFA-1-mediated cellular adhesion to the LFA-1 ligand intercellular adhesion molecule-1 (ICAM-1) through a mechanism involving clustering of LFA-1 molecules, rather than alterations in the level of expression or in the affinity state of this integrin; and (c) induction of cellular polarization and activation of the tyrosine kinase PYK2. Transfection of T-cells with a constitutively active form of Rho (V14Rho) blocks the clustering of LFA-1 on the membrane and the LFA-1-mediated activation of PYK2. Importantly, the activation of PYK2 caused by inhibition of Rho or ROCK takes place only when the T-cells are plated onto ICAM-1 but not when they are either prevented from interacting with ICAM-1 with anti-LFA-1 blocking antibodies or when they are plated on the nonspecific poly-l-lysine substrate. These results indicate that the small GTPase Rho regulates the tyrosine kinase PYK2 in T-cells through the F-actin-mediated control of the activity of the integrin LFA-1. These findings represent a novel paradigm for the regulation of the activity of a cytoplasmic tyrosine kinase by the small GTPase Rho.

Chemokine stromal cell-derived factor-1alpha modulates VLA-4 integrin-dependent adhesion to fibronectin and VCAM-1 on bone marrow hematopoietic progenitor cells.

Stromal cell-derived factor-1alpha (SDF-1alpha) is a potent chemoattractant for hematopoietic progenitor cells (HPC), suggesting that it could play an important role during their migration within or to the bone marrow (BM). The integrin VLA-4 mediates HPC adhesion to BM stroma by interacting with CS-1/fibronectin and VCAM-1. It is required during hematopoiesis and homing of HPC to the BM. As HPC migration in response to SDF-1alpha might require dynamic regulation of integrin function, we investigated if SDF-1alpha could modulate VLA-4 function on BM CD34(hi) cells.CD34(hi) BM cells and hematopoietic cell lines were tested for the effect of SDF-1alpha on VLA-4-dependent adhesion to CS-1/fibronectin and VCAM-1, as well as to BM stroma. CD34(hi) BM cells that adhered to VLA-4 ligands after SDF-1alpha treatment were characterized in colony-forming and long-term culture-initiating cell (LTC-IC) assays.SDF-1alpha rapidly (1 minute) and transiently upregulated the adhesion of CD34(hi) BM cells and hematopoietic cell lines to both CS-1/fibronectin and VCAM-1, and to BM stromal cells. The upregulation of VLA-4-dependent cell adhesion by SDF-1alpha targeted primitive LTC-IC as well as committed CD34(hi) cells. SDF-1alpha-triggered enhancement in VLA-4 function was inhibited by pertussis toxin (PTx) and cytochalasin D, indicating the involvement of G(i) protein downstream signaling and an intact cytoskeleton. Instead, activation of p44/42 MAP kinases by SDF-1alpha did not functionally correlate with enhancement of VLA-4-dependent cell adhesion. Modulation of VLA-4-mediated CD34(hi) BM cell adhesion by SDF-1alpha could play a key role in their migration within and to the BM and therefore influence their proliferation and differentiation.

Alpha4beta1-integrin activation is necessary for high-efficiency T-cell subset interactions with VCAM-1 under flow.

OBJECTIVE: The purpose of this study was to examine the relationship between alpha4beta1-integrin state of activation on CD4+ T-cell subsets and their adhesive interaction to VCAM-1 under flow. METHODS: Human CD4+ memory and naive T-cells were freshly isolated and effector-helper T-cell subsets. Th1 and Th2 cells, were differentiated in vitro from CD4+ naive T-cells. The expression of activation/ligand induced epitopes on beta1-integrins of each T-cell subset was assessed using mAb HUTS21 and mAb 15/7. T-cell subsets attachment and rolling on VCAM-1 was determined under defined flow conditions and the rates of attachment (ka), accumulation, and instantaneous rolling velocities were correlated to their beta1-integrin activation epitope expression. RESULTS: A subset of memory T-cells constitutively express activation/ligand induced epitopes on beta1-integrins recognized by mAb HUTS21 and 15/7, whereas expression levels on naive T-cells is low or not detectable. Consistent with an activated phenotype, memory T-cells exhibit significantly higher rates of attachment and accumulation on VCAM-1 under flow as compared to naive T-cells. Interestingly, the expression of activation/ligand induced epitopes on beta1-integrins on Th2 cells and the ability of these cells to interact with VCAM-1 are comparable to memory T-cells. In contrast, Th1 cells did not interact as efficiently with VCAM-1, which correlated with lower expression of activation/ligand induced epitopes on these cells. VCAM-1 interactions are inhibited completely by pretreatment of the T-cells with blocking mAb to alpha4-integrins or beta1-integrins, indicating that alpha4beta1 is the predominant T-cell integrin involved. CONCLUSIONS: Memory T-cells express constitutively active alpha4beta1-integrins, as compared to naive T-cells, which mediate high rates of initial attachment and sustained high-affinity adhesive interactions with VCAM-1 under flow conditions in vitro. Similarly, in vitro differentiated Th2 cells but not Th1 cells, which also express elevated levels of activated alpha4beta1-integrins, are capable of sustaining high-affinity adhesive interactions with VCAM-1. The differences observed in beta1-integrin activation on T-cell subsets may underlie selective recruitment patterns of T-cell subsets in vivo.

The tyrosine kinase PYK-2/RAFTK regulates natural killer (NK) cell cytotoxic response, and is translocated and activated upon specific target cell recognition and killing.

The compartmentalization of plasma membrane proteins has a key role in regulation of lymphocyte activation and development of immunity. We found that the proline-rich tyrosine kinase-2 (PYK-2/RAFTK) colocalized with the microtubule-organizing center (MTOC) at the trailing edge of migrating natural killer (NK) cells. When polyclonal NK cells bound to K562 targets, PYK-2 translocated to the area of NK-target cell interaction. The specificity of this process was assessed with NK cell clones bearing activatory or inhibitory forms of CD94/NKG2. The translocation of PYK-2, MTOC, and paxillin to the area of NK-target cell contact was regulated upon specific recognition of target cells through NK cell receptors, controlling target cell killing. Furthermore, parallel in vitro kinase assays showed that PYK-2 was activated in response to signals that specifically triggered its translocation and NK cell mediated cytotoxicity. The overexpression of both the wt and a dominant-negative mutant of PYK-2, but not ZAP-70 wt, prevented the specific translocation of the MTOC and paxillin, and blocked the cytotoxic response of NK cells. Our data indicate that subcellular compartmentalization of PYK-2 correlates with effective signal transduction. Furthermore, they also suggest an important role for PYK-2 on the assembly of the signaling complexes that regulate the cytotoxic response.

Paxillin localizes to the lymphocyte microtubule organizing center and associates with the microtubule cytoskeleton.

Paxillin is a focal adhesion-associated protein that functions as a multi-domain adapter protein, binding several structural and signaling molecules. alpha-Tubulin was identified as an interacting protein in a two-hybrid screen using the paxillin C-terminal LIM domain as a bait. In vitro binding assays with glutathione S-transferase-paxillin demonstrated an interaction of alpha-tubulin with the C terminus of paxillin. Another member of the tubulin family, gamma-tubulin, bound to both the N and the C terminus of paxillin. The interaction between paxillin and both alpha- and gamma-tubulin in vivo was confirmed by co-immunoprecipitation from human T lymphoblasts. Immunofluorescence studies revealed that, in adherent T cells, paxillin localized to sites of cell-matrix interaction as well as to a large perinuclear region. Confocal microscopy revealed that this region corresponds to the lymphocyte microtubule organizing center, where paxillin colocalizes with alpha- and gamma-tubulin. The localization of paxillin to this area was observed in cells in suspension as well as during adhesion to integrin ligands. These data constitute the first characterization of the interaction of paxillin with the microtubule cytoskeleton, and suggest that paxillin, in addition to its well established role at focal adhesions, could also be associated with the lymphocyte microtubule network.

Activation-dependent changes in soluble fibronectin binding and expression of beta1 integrin activation epitopes in T cells: relationship to T cell adhesion and migration.

The relationship between activation-dependent changes in beta1 integrin conformation, T cell adhesion to immobilized fibronectin, and T cell migration in vitro was analyzed in this study. Stimulation of Jurkat T cells and peripheral T cells with Mn(2+), the activating beta1 integrin-specific monoclonal antibody (mAb) TS2 /16, CD2, or CD28 stimulation led to increased adhesion, soluble fibronectin (FN) binding and expression of the activation epitope defined by the beta1 integrin mAb HUTS-21. Phorbol 12-myristate 13-acetate treatment increased adhesion, but not soluble FN binding or HUTS-21 epitope expression. In peripheral T cells, CD3 or CD7 stimulation also led to increased adhesion, soluble FN binding and HUTS-21 epitope expression. Soluble FN blocked peripheral T cell adhesion induced by Mn(2+) or TS2/16, but had no effect on adhesion induced by the other integrin-activating signals. In contrast, migration induced by TS2/16, CD2, CD3, CD7 or CD28 stimulation was blocked by excess soluble FN. Phosphoinositide 3-OH kinase (PI 3-K) inhibitors blocked receptor-mediated increases in cell adhesion, but not soluble FN binding or HUTS-21 expression. Migration was similarly unaffected by PI 3-K inhibitors, with the exception of CD7- and CD28-induced migration, which was specifically blocked by LY294,002. These results suggest that activation-dependent changes in beta1 integrin conformation are PI 3-K-independent and are involved in T cell migration but not adhesion.

Endoglin is expressed in the chicken vasculature and is involved in angiogenesis.

Endoglin is a component of the transforming growth factor beta (TGF-beta) receptor complex, highly expressed by endothelial cells. Mutations in the endoglin gene are responsible for hereditary hemorrhagic telangiectasia type 1 (HHT1), an autosomal dominant vascular disorder caused by a haploinsufficiency mechanism. Vascular lesions (telangiectasia and arteriovenous malformations) in HHT1 are associated with loss of the capillary network, suggesting the involvement of endoglin in vascular repair processes. Using the chick chorioallantoic membrane (CAM) as an angiogenic model, we have analyzed the expression and function of chicken endoglin. A pan-specific polyclonal antibody (pAb) recognized chicken endoglin as demonstrated by immunostaining and Western blot analysis. In ovo treatment of chicken embryos with this pAb resulted in a significantly increased area of CAM. This effect was likely mediated by modulation of the ligand binding to endoglin as this pAb was able to inhibit TGF-beta1 binding. These results support the involvement of endoglin in the angiogenic process.

Signaling through CD43 induces natural killer cell activation, chemokine release, and PYK-2 activation.

Natural killer (NK) cell activation is the result of a balance between positive and negative signals triggered by specific membrane receptors. We report here the activation of NK cells induced through the transmembrane glycoprotein CD43 (leukosialin, sialophorin). Engagement of CD43 by specific antibodies stimulated the secretion of the chemokines RANTES, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta, which was prevented by treatment of cells with the specific tyrosine kinase inhibitor genistein. Furthermore, signaling through CD43 increased the cytotoxic activity of NK cells and stimulated an increase in the tyrosine kinase activity in antiphosphotyrosine immune complexes of NK cell lysates. PYK-2 was identified among the tyrosine kinase proteins that become activated. Hence, PYK-2 activation was observed after 20 minutes of CD43 stimulation, reached a maximum after 45 to 60 minutes, and decreased to almost basal levels after 120 minutes of treatment. Together, these results demonstrate the role of CD43 as an activation molecule able to transduce positive activation signals in NK cells, including the regulation of chemokine synthesis, killing activity, and tyrosine kinase activation.