Resumo Desde a fundação do Centro Malacológico em 1980, a Universidad Central Americana (UCA), Manágua-Nicarágua, vem acompanhando e coletando a população de moluscos marinhos, terrestres, fluviais e lagoas do país. Muitos espécimes foram fotografados pelo microscópio eletrônico de varredura (SEM) e, em um deles, a observação do periostracum peludo revela uma população aparentemente próspera de protistas de minuto em possível simbiose com o hospedeiro. A ampliação adequada e a comparação com estudos anteriores permitem a determinação dessas diatomáceas, amebas testaceas, leveduras, phacus, esporos e outros organismos indeterminados que ocorrem em florestas tropicais em rochas, árvores e folhas. Aqui estão as diatomeas e outros organismos pela primeira vez detectados no periostracum de um molusco tropical.

Abstract Since the foundation of the Malacological Center in 1980, Universidad Centro Americana (UCA), Managua-Nicaragua, has been monitoring and collecting the marine, terrestrial, fluvial and lake mollusk population of the country. Many specimens have been photographed by Scanning Electronic Microscope (SEM), and in one of these, observation of the hairy periostracum reveals a seemingly thriving population of minute protists in possible symbiosis with their host. Adequate magnification and comparison with previous studies allowed the determination of these hosts as diatoms, testaceous amoebae, yeast, phacus, spores and other undetermined organisms which occur in tropical forests on rocks, trees and leaves. Here illustrated are diatoms and other organisms detected for the first time on the periostracum of a tropical rainforest mollusk.

In our Universitary Hospital of Canarias we iniciated in May 2008 a induction therapy protocol for sensitized patients receiving cadaveric renal graft using intravenous immunoglobulins, plasmapheresis and rituximab plus immunosuppression with prednisone, tacrolimus and mycophenolate mofetil. We present the results of four patients. Everyone had anti-HLA antibodies rate (PRA by CDC) more than 75%, were on a waiting list during 4 to 17 years and follow-up time was 10-14 months after transplantation. Patient and graft survival in this period was 100%. Only one patient suffered a humoral acute rejection and another one cellular rejection, in both cases reversible with treatment. During the first year, no evidence of de novo donor-specific antibodies was detected. All patients had significantly reduced the CD19+ cells percentage after infusion of rituximab. Neurological symptoms suggestive of progressive multifocal leukoencephalopathy or serious viral infections after transplantation have not been observed. Additionally, no immediate side effects were observed after administration of medication. In summary, induction therapy by combining immunoglobulin, plasmapheresis and rituximab in hypersensitive patients allows the realization of deceased kidney transplantation with good results in the short and medium-term without serious side effects. It remains to know whether this success will continue in the long term.

En el Hospital Universitario de Canarias pusimos en marcha, en mayo de 2008, un protocolo de tratamiento de inducción para pacientes hipersensibilizados que reciben injerto renal de cadáver utilizando inmunoglobulinas intravenosas, plasmaféresis y rituximab más una inmunosupresión triple con prednisona, tacrolimus y micofenolato mofetil. Presentamos los resultados de 4 pacientes. Todos ellos presentaban una tasa de anticuerpos anti-HLA (PRA por CDC) superior al 75%, llevaban en lista de espera de 4 a 17 años, el tiempo de seguimiento posterior al trasplante fue de 10-14 meses y la supervivencia de paciente y del injerto en este período fue del 100%. Sólo un paciente sufrió un rechazo agudo mediado por anticuerpos y otro uno celular, en ambos casos reversibles con el tratamiento. En la evolución no se objetivó aparición de novo de anticuerpos donante-específicos. Todos los pacientes habían reducido significativamente el número de células CD19+ después de la infusión de rituximab. No se han detectado síntomas neurológicos indicativos de leucoencefalopatía multifocal progresiva ni infecciones virales graves después del trasplante y tampoco se han observado efectos secundarios inmediatos tras la administración de la medicación. En resumen, el tratamiento de inducción combinado con inmunoglobulinas, plasmaféresis y rituximab en pacientes hipersensibilizados permite la realización del trasplante renal procedente de donante cadáver con buenos resultados a corto y medio plazo y sin graves efectos secundarios. Queda por conocer si estos buenos resultados se mantendrán a más largo plazo.