Synthesis of new antibacterial composite coating for titanium based on highly ordered nanoporous silica and silver nanoparticles.

Infection is the most common factor that leads to dental titanium implant failure. Antibacterial implant surfaces based on nano-scale modifications of the titanium appear as an attractive strategy for control of peri-implantitis. In the present work, the preparation and antibacterial properties of a novel composite coating for titanium based on nanoporous silica and silver nanoparticles are presented. Starch-capped silver nanoparticles (AgNPs) were synthesized and then incorporated into sol-gel based solution system. The AgNP-doped nanoporous silica coatings were prepared on titanium surface using a combined sol-gel and evaporation-induced self-assembly (EISA) method. The coating nanostructure was characterized by XRD, SEM-EDX, and HR-TEM. Antibacterial activity was evaluated against Aggregatibacter actinomycetemcomitans, a representative pathogen of dental peri-implantitis. Colony-forming units (CFUs) were counted within the biofilm and at the planktonic state. Biofilm development was quantified using crystal violet staining and viability of adherent bacteria was confirmed with the Live/Dead fluorescence assay. Silica-based composite coating containing AgNPs (AgNP/NSC) was prepared on titanium surface by direct incorporation of AgNP suspension into the sol-gel system. The self-assembly technique enabled the spontaneous formation of a highly ordered nanoporosity in the coating structure, which is a desired property for osseointegration aspects of titanium implant surface. AgNP/NSC coating produces a strong antibacterial effect on titanium surface by not only killing the adherent bacteria but also reducing the extent of biofilm formation. Biofilm survival is reduced by more than 70% on the AgNP/NSC-modified titanium surface, compared to the control. This antibacterial effect was verified for up to 7 days of incubation. The long-term antibacterial activity exhibited by the nanostructured AgNP/NSC-titanium surface against A. actinomycetemcomitans suggests that this type of nano-scale surface modification is a promissory strategy to control infections associated with dental implant rehabilitation.

[Mediastinal sarcoidal reaction in follow up for seminoma]. / Reaccion sarcoidal mediastinal en el seguimiento de un paciente con seminoma.

Mediastinal sarcoidal reaction in follow up for seminoma. Testicular germ cell tumors constitute a model for curable neoplasia. Long-term complications are well-known and follow-up includes not only awareness of relapse, but also of the development of secondary tumors and treatment sequelae. In the last two decades, an increase in sarcoidosis incidence has been described in cured patients, who at follow-up present lung nodules or mediastinal lymph nodes. A 28 year-old patient who, on clinical follow up of a semi-nomatous tumor, presented mediastinal lymph nodes on CT scan and chest x-ray, without evidence of disease in pelvis or abdomen is presented. His other testicle was normal and he had negative tumor markers. Because of this rare presentation, a mediastinoscopy was performed and sarcoidosis like reaction was diagnosed. During follow-up of patients with testicular germ cell tumors, the presence of mediastinal lymph nodes requires a histological diagnosis and sarcoidosis should be considered as differential diagnosis.

Reacción sarcoidal mediastinal en el seguimiento de un paciente con seminoma / Mediastinal sarcoidal reaction in follow up for seminoma

El cáncer de células germinales de testículo es el modelo de neoplasia curable. Las complicaciones a largo plazo son bien conocidas y el seguimiento incluye la pesquisa no sólo de la recaída, sino también de la aparición de segundos tumores y secuelas del tratamiento empleado. Un aumento de la incidencia de lesiones con granulomas tipo sarcoidosis se ha descripto en las últimas dos décadas en pacientes curados quienes en el seguimiento se presentan con nódulos pulmonares o adenopatías mediastinales.Se presenta el caso clínico de un paciente de 28 años quien durante el seguimiento clínico por un tumor seminomatoso, muestra en la tomografía axial computada y radiografía de tórax la presencia de adenopatías en mediastino, sin evidencia de enfermedad en abdomen y pelvis, el otro testículo normal y marcadores negativos.Ante esta peculiar situación, se realiza mediastinoscopia diagnosticándose reacción sarcoidal en ganglio mediastinal. Durante el seguimiento de pacientes con tumores germinales de testículo la presencia de adenopatías mediastinales exige contar con el diagnóstico histológico y tener en cuenta a la sarcoidosis en el diagnóstico diferencial

Testicular germ cell tumors constitute a model for curable neoplasia. Long-term complications are well-known and follow-up includes not only awareness of relapse, but also of the development of secondary tumors and treatment sequelae. In the last two decades, an increase in sarcoidosis incidence has been described in cured patients, who at follow-up present lung nodules or mediastinal lymph nodes. A 28 year-old patient who, on clinical follow up of a seminomatous tumor, presented mediastinal lymph nodes on CT scan and chest x-ray, without evidence of disease in pelvis or abdomen is presented. His other testicle was normal and he had negative tumor markers. Because of this rare presentation, a mediastinoscopy was performed and sarcoidosis like reaction was diagnosed. During follow-up of patients with testicular germ cell tumors, the presence of mediastinal lymph nodes requires a histological diagnosis and sarcoidosis should be considered as differential diagnosis