Effect of Spin Clustering on Basic and Relaxometric Properties of Magnetic Nanoparticles.

An increasing awareness about novel medical applications of smaller, inorganic-based nanoparticles, possessing unique properties at the nanoscale, has led to a burst of research activities in the development of "nanoprobes" for diagnostic medicine and agents for novel, externally activated therapies. In this research field magnetic nanoparticles are prominent due to fundamental peculiar properties particularly appealing for their use in materials and biomedical applications. Aiming to study the relationship between the topology of the magnetic nanoparticles and their efficacy as MRI contrast agents (relaxometric properties), we prepared three different stable colloidal suspension (ferrofluid) of magnetic nanobeads (MNBs) constituted by a discrete number of maghemite nanoparticles, arranged in disordered clusters or ordered in a polymeric matrix. An accurate morpho-dimensional and magnetic characterization displays the close correlation between the magnetic fundamental properties and the topology of our spin systems. The NMR relaxometry profiles confirmed the nature of the physical mechanisms inducing the increase of nuclear relaxation rates at low (magnetic anisotropy) and high (Curie relaxation) magnetic fields. Moreover the transverse relaxivity (r2) values for all the MNBs are higher than those of common contrast agents and the differences between the three MNBs are suggested to be due to the spin topology effect.

Prevalencia de psoriasis secundaria a agentes biológicos en pacientes con artritis reumatoidea / Prevalence of psoriasis in patients with rheumatoid arthritis treated with biological agents

Los objetivos del estudio fueron determinar la prevalencia de psoriasis en pacientes con Artritis Reumatoidea (AR) tratados con Agentes Biológicos (AB) y analizar sus características clínicas en una población de Tucumán.Se incluyeron 284 pacientes con AR. Ciento cuarenta y ocho en tratamiento con AB y 136 pacientes en tratamiento con Drogas Modificadoras de AR (DMAR), seleccionados por muestreo aleatorio simple. De los 284 pacientes evaluados, 242 (85%) fueron de sexo femenino, edad media de 56,4 años ± 13,4, la edad media al diagnóstico de AR fue de 42,3 años ± 16,7 con un tiempo de evolución de la enfermedad de 11,9 años ± 8,5. Doscientos cuarenta y un pacientes (85%) fueron seropositivos para Factor Reumatoideo (FR). Ciento treinta y seis (48%) fueron tratados con DMAR y 148 (52%) con AB. Al comparar ambos grupos, no hubo diferencias significativas entre edad media, edad media al diagnóstico de AR y presencia de factor reumatoideo. Cinco de los 148 pacientes en tratamiento biológico desarrollaron psoriasis. La prevalencia de psoriasis cutánea fue 3,4% (IC 95% 1,1-7,7). La mayoría de los casos se presentaron como psoriasis gutata. La duración media del tratamiento hasta la aparición de psoriasis fue de 31,6 meses (DS 26,8). Un paciente teníaantecedentes familiares de psoriasis. Ningún paciente del grupo DMAR desarrolló psoriasis (p <0,0001). En 2 pacientes que suspendieron el AB hubo remisión completa de la manifestación cutánea y en 3 pacientes que mantuvieron el tratamiento las manifestaciones cutáneas persistieron. No se encontró asociación entre el desarrollo de psoriasis y edad al diagnóstico, tiempo de evolución de AR y tiempo de tratamiento con AB (p = NS). Concluimos que la prevalencia de psoriasis en pacientes tratados con AB (etanercept, adalimumab y abatacept) fue 3,4%. El desarrollo de psoriasis cutánea no se asoció a edad al diagnóstico, tiempo de evolución de AR ni tiempo de tratamiento con agentes biológicos.

The objectives of this study were to determine the prevalence of psoriasis in patients with rheumatoid arthritis (RA) who were treated with biological agents (BA) and analize its clinical features in apopulation of Tucumán. We included 284 patients with RA. One hundred and forty-eight patients received treated with AB and 136 patients were treated with disease modifying anti-rheumatic drugs (DMARD), and they were selected by simple random sampling. Of the 284 patients evaluated, 242 (85%) were female, mean age was 56.4 ± 13.4 years, mean age at diagnosis of RA was 42.3 ± 16.7 years with a mean time of disease progression of 11.9 ± 8.5 years. Two hundred and fourty-one patients (85%) were seropositive for rheumatoid factor. One hundred thirty-six patients (48%) were treated with DMARD and 148 (52%) received BA. When we compared both groups, there was no significant difference between mean age, age at diagnosis of RA and presence of rheumatoid factor.Five of 148 patients developed psoriasis in the BA group, after receiving the first BA. The prevalence of cutaneous psoriasis was 3.4% (95% CI 1.1-7.7). Most cases were presented as gutata psoriasis. The average duration of treatment to onset of psoriasis was31.6 months (SD 26.8). One patient had a family history of psoriasis. In the group with DMARD, neither patient developed psoriasis (p<0.0001). Remission of the cutaneous manifestation was observed in 2 patients that discontinued the BA and 3 maintained treatment with persistance of the symptoms. No association was found between the development of psoriasis and age at diagnosis, RA duration and treatment time with BA (p = NS). We conclude that the prevalence of psoriasis in patients treated with BA (etanercept, adalimumab and abatacept) was 3.4%. The development of skin psoriasis was not associated with age at diagnosis, RA duration or time of treatment with biological agents.

Prevalencia de psoriasis secundaria a agentes biológicos en pacientes con artritis reumatoidea / Prevalence of psoriasis in patients with rheumatoid arthritis treated with biological agents

Los objetivos del estudio fueron determinar la prevalencia de psoriasis en pacientes con Artritis Reumatoidea (AR) tratados con Agentes Biológicos (AB) y analizar sus características clínicas en una población de Tucumán.Se incluyeron 284 pacientes con AR. Ciento cuarenta y ocho en tratamiento con AB y 136 pacientes en tratamiento con Drogas Modificadoras de AR (DMAR), seleccionados por muestreo aleatorio simple. De los 284 pacientes evaluados, 242 (85%) fueron de sexo femenino, edad media de 56,4 años ± 13,4, la edad media al diagnóstico de AR fue de 42,3 años ± 16,7 con un tiempo de evolución de la enfermedad de 11,9 años ± 8,5. Doscientos cuarenta y un pacientes (85%) fueron seropositivos para Factor Reumatoideo (FR). Ciento treinta y seis (48%) fueron tratados con DMAR y 148 (52%) con AB. Al comparar ambos grupos, no hubo diferencias significativas entre edad media, edad media al diagnóstico de AR y presencia de factor reumatoideo. Cinco de los 148 pacientes en tratamiento biológico desarrollaron psoriasis. La prevalencia de psoriasis cutánea fue 3,4% (IC 95% 1,1-7,7). La mayoría de los casos se presentaron como psoriasis gutata. La duración media del tratamiento hasta la aparición de psoriasis fue de 31,6 meses (DS 26,8). Un paciente teníaantecedentes familiares de psoriasis. Ningún paciente del grupo DMAR desarrolló psoriasis (p <0,0001). En 2 pacientes que suspendieron el AB hubo remisión completa de la manifestación cutánea y en 3 pacientes que mantuvieron el tratamiento las manifestaciones cutáneas persistieron. No se encontró asociación entre el desarrollo de psoriasis y edad al diagnóstico, tiempo de evolución de AR y tiempo de tratamiento con AB (p = NS). Concluimos que la prevalencia de psoriasis en pacientes tratados con AB (etanercept, adalimumab y abatacept) fue 3,4%. El desarrollo de psoriasis cutánea no se asoció a edad al diagnóstico, tiempo de evolución de AR ni tiempo de tratamiento con agentes biológicos.(AU)

The objectives of this study were to determine the prevalence of psoriasis in patients with rheumatoid arthritis (RA) who were treated with biological agents (BA) and analize its clinical features in apopulation of Tucumán. We included 284 patients with RA. One hundred and forty-eight patients received treated with AB and 136 patients were treated with disease modifying anti-rheumatic drugs (DMARD), and they were selected by simple random sampling. Of the 284 patients evaluated, 242 (85%) were female, mean age was 56.4 ± 13.4 years, mean age at diagnosis of RA was 42.3 ± 16.7 years with a mean time of disease progression of 11.9 ± 8.5 years. Two hundred and fourty-one patients (85%) were seropositive for rheumatoid factor. One hundred thirty-six patients (48%) were treated with DMARD and 148 (52%) received BA. When we compared both groups, there was no significant difference between mean age, age at diagnosis of RA and presence of rheumatoid factor.Five of 148 patients developed psoriasis in the BA group, after receiving the first BA. The prevalence of cutaneous psoriasis was 3.4% (95% CI 1.1-7.7). Most cases were presented as gutata psoriasis. The average duration of treatment to onset of psoriasis was31.6 months (SD 26.8). One patient had a family history of psoriasis. In the group with DMARD, neither patient developed psoriasis (p<0.0001). Remission of the cutaneous manifestation was observed in 2 patients that discontinued the BA and 3 maintained treatment with persistance of the symptoms. No association was found between the development of psoriasis and age at diagnosis, RA duration and treatment time with BA (p = NS). We conclude that the prevalence of psoriasis in patients treated with BA (etanercept, adalimumab and abatacept) was 3.4%. The development of skin psoriasis was not associated with age at diagnosis, RA duration or time of treatment with biological agents.(AU)

Entrapping molecules in zeolites nanocavities: a thermodynamic and ab-initio study.

Adsorption enthalpies of Ar, N2, CO, H2O, CH3CN and NH3 on H-BEA and H-MFI zeolites and on Silicalite, have been measured calorimetrically at 303K in order to assess the energetic features of dispersive forces interactions (confinement effects), H-bonding interactions with surface silanols and specific interactions with Lewis and Brønsted acidic sites. The adsorption of the molecular probes with model clusters mimicking surface silanols, Lewis and Brønsted sites has been simulated at ab-initio level. The combined use of the two different approaches allowed to discriminate among the different processes contributing to the measured (-deltaadsH). Whereas CO and N2 single out contributions from Lewis and Brønsted acidic sites, Ar is only sensitive to confinement effects. For H2O, CH3CN and NH3 the adsorption on Brønsted sites is competitive with the adsorption on Lewis sites. The energy of interaction of H2O with all considered zeolites is surprisingly higher than expected on the basis of -deltaadsH vs PA correlation.