Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution.

The tribo-electrochemical behavior of different ß titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where "x" is the weight percentage of Sn content, 2% and 4%). Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between -1 and 2V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn. Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys.

Electrochemical behavior of near-beta titanium biomedical alloys in phosphate buffer saline solution.

The electrochemical behavior of three different near-ß titanium alloys (composed by Ti, Nb and Sn) obtained by powder metallurgy for biomedical applications has been investigated. Different electrochemical and microscopy techniques were used to study the influence of the chemical composition (Sn content) and the applied potential on the microstructure and the corrosion mechanisms of those titanium alloys. The addition of Sn below 4wt.% to the titanium powder improves the microstructural homogeneity and generates an alloy with high corrosion resistance with low elastic modulus, being more suitable as a biomaterial. When the Sn content is above 4%, the corrosion resistance considerably decreases by increasing the passive dissolution rate; this effect is enhanced with the applied potential.

Values for αß and γδ T-lymphocytes and CD4+, CD8+, and CD56+ subsets in healthy adult subjects: assessment by age and gender.

BACKGROUND: Normal reference values in healthy subjects for T-lymphocytes for both types of receptors, αß and γδ, and their subsets are yet to be defined. The aim of this study was to measure peripheral blood αß and γδ total T-lymphocytes and their subsets in a population of healthy subjects, in order to obtain valid reference values for studies in human pathology. METHODS: We studied a total of 157 healthy subjects, 78 men and 79 women, establishing their levels of CD3+, CD4+, CD8+, CD56+, αßCD3+, αßCD3+CD4+, αßCD3+CD8+, αßCD3+CD56+, γδCD3+, γδCD3+CD4-CD8-, γδCD3+CD8+, and γδCD3+CD56+ T-cells by flow cytometry. The T-cell subsets were compared for different age and gender groups. RESULTS: A significant decrease in CD3+, CD3+CD4+, CD3+CD4+ αß, and CD3+ γδ T-cells was observed in elderly subjects. CD3+, CD3+ αß, and CD3+CD4+ αß T-cells increased in women, while CD3+CD56+ αß T-cells increased in men. CONCLUSIONS.: These reference values could be useful in further research studies for assessing changes that occur in the different αß and γδ T subsets in human pathology.

Application of the Zero-Order Reaction Rate Model and Transition State Theory to predict porous Ti6Al4V bending strength.

Porous Ti6Al4V samples were produced by microsphere sintering. The Zero-Order Reaction Rate Model and Transition State Theory were used to model the sintering process and to estimate the bending strength of the porous samples developed. The evolution of the surface area during the sintering process was used to obtain sintering parameters (sintering constant, activation energy, frequency factor, constant of activation and Gibbs energy of activation). These were then correlated with the bending strength in order to obtain a simple model with which to estimate the evolution of the bending strength of the samples when the sintering temperature and time are modified: σY=P+B·[lnT·t-ΔGa/R·T]. Although the sintering parameters were obtained only for the microsphere sizes analysed here, the strength of intermediate sizes could easily be estimated following this model.

Differential effect of appendectomy and tonsillectomy on anti-Kudoa sp. antibodies in patients with MALTectomy.

We found an association between tonsillectomized patients and subsequent appendicitis. We also observed that MALTectomy significantly decreased secretory IgA levels in serum of patients, being this decrease more pronounced when both operations (tonsillectomy and appendectomy) had been performed. The elevated humoral responses detected previously by us in BALB/c mice immunized with Kudoa sp. pseudocyst extracts and the high IgG1 and IgE levels induced by the oral administration of Kudoa sp. pseudocysts to BALB/c mice showed the possible immunopathological effects in man from the ingestion of Kudoa sp. infected fish. We use the ELISA method to investigate the possible relationship between MALTectomy (tonsillectomy and appendectomy) and specific antibody levels to Kudoa sp. Both anti-Kudoa sp. specific antibody levels and the number of patients that recognized Kudoa sp. antigens were greater in tonsillectomy patients when compared to the control and the other studied groups (appendectomized and appendectomized+tonsillectomies patients). Tonsillectomy was associated to a switch in the class of immunoglobulins involved in these responses and these responses may be abrogated by appendectomy. Tonsils and appendix may respond in different ways to Kudoa sp. antigens and these different reactions may be involved in some immunopathological reactions.

Neumonía comunitaria grave por legionella pneumophila / Severe community-acquired pneumonia due to legionella pneumophila

Legionella pneumophila (LP) es la segunda causa de neumonía comunitaria en nuestro medio, y un elevado porcentaje de casos precisan ingreso en unidades de cuidados intensivos (UCI), con una elevada mortalidad. Presentamos 3 casos de neumonía comunitaria grave (NCG) por LP. El motivo de ingreso en todos los casos fue insuficiencia respiratoria. Al ser tanto la clínica como la radiología torácica inespecíficas, se llegó al diagnóstico mediante pruebas complementarias, siendo positivas las antigenurias para LP en los tres pacientes y sólo en dos de los casos la serología era positiva para el serogrupo 1. Se realizó tratamiento antimicrobiano empírico con fluoroquinolonas (levofloxacino) y cefalosporinas de tercera generación (ceftriaxona). Dos pacientes presentaron una mala evolución clínica, desarrollando un cuadro de disfunción multiorgánica, motivo finalmente de los fallecimientos. El tercer caso evolucionó de manera favorable, siendo dado de alta a las 48 horas del ingreso. (AU)

[Primary Sjogren's syndrome in men: evolution to acute lymphoblastic leukemia]. / Síndrome de Sjögren primario en varón: evolución a leucemia linfoblástica aguda.

A clinical case of a 55-year-old man with syndrome of primary Sjögren, seronegative, normoglobulinemic and normocomplementary with 7 years of evolution, which developed acute lymphoblastic leukemia, having suffered recurrent lympho-adenopathy and paresthetic meralgia as previous clinical signs, is presented. Clinical, serological and immunologic characteristics of this syndrome are reviewed, highlighting its rare appearance among men. While appearance of malignant lymphoproliferation disorders is well known, evolution to acute or chronic myeloid leukemia is very rare and so far, an acute lymphoblastic leukemia as the one presented in this study has never been described.

Prognostic factors in chronic myelodysplastic syndromes: a multivariate analysis in 107 cases.

A retrospective multivariate analysis of 37 clinical, biochemical, and hematological data was performed in 107 cases of primary myelodysplastic syndromes (MDS) in order to recognize their prognostic significance. The most important individual variables, isolated in a previous univariate analysis, were placed in a multiple regression modeling procedure to identify major significant prognostic factors. Multivariate analysis tends to identify prognostic variables containing significant independent predictive information. Characteristics were examined on both continuous and binary bases. The FAB classification was the first parameter entered in regression equations on both models, followed by platelet count, hemoglobin level, and circulating erythroblasts in the binary model, and by hemoglobin level, systemic symptoms, platelet count, age, and dyserythropoiesis in the continuous model. Our analysis confirms FAB classification as the main prognostic factor in MDS, supports the previously noted predictive value of platelet count, hemoglobin level, and age, and recognises the importance of circulating erythroblasts, systemic symptoms, and dyserythropoiesis as prognostic characteristics in MDS.

Trisomy 4: another specific anomaly in acute nonlymphocytic leukemia.

We present herein a case of acute nonlymphocytic leukemia, type M2 of the FAB classification, in which the cytogenetic study of the bone marrow cells showed a trisomy 4 as the only alteration. This case was detected from among 118 cases of acute nonlymphocytic leukemia under cytogenetic study.

Translocation (15;17) in a child with variant form of acute promyelocytic leukemia.

We present the cytogenetic and hematologic study of a 6-year-old child with a variant form of acute promyelocytic leukemia (M3) who died of a brain hemorrhage. The brief survival and the hyperleukocytosis (greater than 200,000 mm3) suggests a very bad prognosis in children with this variant form of M3 leukemia.