[Nanotechnology applied to the transport of antibiotics in orthopedics and traumatology]. / Nanotecnología aplicada a la transportación de antibióticos en ortopedia y traumatología.

Bone infection and implants are a real problem in orthopedics. The formation of biofilm as well as multi-existing pathogens to antibiotics, make fighting them a difficult challenge with the tools we have today. With the aim of knowing the current state of nanotechnology applied to the transport of antibiotics in traumatology and orthopedics, and their projection in the future. We conducted a bibliographic review in June 2019. While much development of the topic and work on humans is lacking, experimental studies show that nanotechnology applied to antibiotic transport promises to be an important weapon in the treatment of bone infections in the future.

La infección ósea y de los implantes son un verdadero problema en traumatología y ortopedia. La formación de biofilm, así como patógenos multirresistentes a antibióticos hacen que combatirlas sea un difícil reto con las herramientas que hoy tenemos. Con el objetivo de conocer el estado actual de la nanotecnología, aplicada a la transportación de antibióticos en traumatología y ortopedia y su proyección a futuro, realizamos una revisión bibliográfica en Junio de 2019. Si bien falta mucho desarrollo del tema y trabajos sobre humanos, los estudios experimentales muestran que la nanotecnología aplicada a la transportación de antibióticos promete ser un arma importante en el tratamiento de las infecciones óseas a futuro.

Rubber Tree (Hevea brasiliensis) Bark Necrosis Syndrome I: Still No Evidence of a Biotic Causal Agent.

The main constraint in rubber plantations worldwide is the cessation of latex production because of two syndromes: (i) tapping panel dryness (TPD), a reversible physiological response to overexploitation; and (ii) bark necrosis (BN), an irreversible syndrome spreading from the collar toward the tapping cut. Early BN symptoms develop in the inner phloem tissues but never affect the cambium. Necrotic patches appear in the outer phloem, inducing bark cracking and peeling, but these alterations never lead to tree death. BN spreads gradually to neighboring rubber trees, and evidence of linear disease centers suggest that a pathogen may be involved, possibly transmitted by the tapping knife. Several previous etiological investigations (fungi, phytoplasma, bacteria, and virus) were performed (3) on leaves, bark, and latex using different methods (e.g., isolation, transmission, chemical treatments, and optic and electron microscope studies). Recent works focused on mechanically transmissible pathogens, such as viroid (2) or virus/double strand RNA, using RNA extraction (nonionic cellulose and appropriate ethanol concentrations) and treatment with RNase A, followed with sequential polyacrylamide gel electrophoresis (s-PAGE), reverse transcription-polymerase chain reaction (RT-PCR), degenerate oligonucleotide primer-PCR (DOP-PCR), and cloning and sequence analysis. While numerous viroid-like (between 250 and 400 nucleotides) and double strand virus-like (1,800 bp) low-molecular-weight RNAs were observed, no definite correlation was found with the BN status of trees. Sequencing of the various isolated RNAs only identified plasmids, nonpathogenic bacteria and yeasts, but none of the suspected pathogens. In addition, previous and recent transmission trials (tapping knife disinfection, bud grafting, bark implantation, and etc.) failed to confirm the involvement of a biotic agent. In conclusion, since these etiological investigations were inconclusive, a physiological disease is now suspected that involves exogenous stresses, nonoptimal vascular relations at the rootstock/scion junction and impaired cyanide metabolism (1,4). References: (1) H. Chrestin et al. Plant Dis. 88:1047, 2004. (2) N. Duran-Vila et al. J. Gen. Virol. 69:3069, 1988. (3) D. Nandris et al. Eur. J. For. Pathol. 21:340, 1991. (4) D. Nandris et al. Plant Dis. 88:1047, 2004.

Sudden Death of Citrus in Brazil: A Graft-Transmissible Bud Union Disease.

Citrus Sudden Death (CSD), a new, graft-transmissible disease of sweet orange and mandarin trees grafted on Rangpur lime rootstock, was first seen in 1999 in Brazil, where it is present in the southern Triângulo Mineiro and northwestern São Paulo State. The disease is a serious threat to the citrus industry, as 85% of 200 million sweet orange trees in the State of São Paulo are grafted on Rangpur lime. After showing general decline symptoms, affected trees suddenly collapse and die, in a manner similar to trees grafted on sour orange rootstock when affected by tristeza decline caused by infection with Citrus tristeza virus (CTV). In tristeza-affected trees, the sour orange bark near the bud union undergoes profound anatomical changes. Light and electron microscopic studies showed very similar changes in the Rangpur lime bark below the bud union of CSD-affected trees: size reduction of phloem cells, collapse and necrosis of sieve tubes, overproduction and degradation of phloem, accumulation of nonfunctioning phloem (NFP), and invasion of the cortex by old NFP. In both diseases, the sweet orange bark near the bud union was also affected by necrosis of sieve tubes, and the phloem parenchyma contained characteristic "chromatic" cells. In CSD-affected trees, these cells were seen not only in the sweet orange phloem, but also in the Rangpur lime phloem. Recent observations indicated that CSD affected not only citrus trees grafted on Rangpur lime but also those on Volkamer lemon, with anatomical symptoms similar to those seen in Rangpur lime bark. Trees on alternative rootstocks, such as Cleopatra mandarin and Swingle citrumelo, showed no symptoms of CSD. CSD-affected trees did recover when they were inarched with seedlings of these rootstocks, but not when inarched with Rangpur lime seedlings. These results indicate that CSD is a bud union disease. In addition, the bark of inarched Rangpur lime and Volkamer lemon seedlings showed, near the approach-graft union, the same anatomical alterations as the bud union bark from the Rangpur lime rootstock in CSD-affected trees. The dsRNA patterns from CSD-affected trees and unaffected trees were similar and indicative of CTV. CSD-affected trees did not react by immunoprinting-ELISA using monoclonal antibodies against 11 viruses. No evidence supported the involvement of viroids in CSD. The potential involvement of CTV and other viruses in CSD is discussed.

Cryopreservation of ovules and somatic embryos of citrus using the encapsulation-dehydration technique.

Cryopreservation of ovules and somatic embryos from several genotypes of citrus was achieved using the encapsulation-dehydration technique. Survival of cryopreserved ovules was occasional and erratic after different pregrowth conditions in liquid medium with 0.75M, 1M or up to 1.25M sucrose. An efficient cryopreservation protocol was established for somatic embryos derived from two embryogenic sources (ovules and cut thin layer explants from stigma, style and ovaries). High survival rates (75-100%) were consistently obtained after 1 day pregrowth in 0.75M sucrose, desiccation down to 20-25% moisture content in the beads and direct immersion in liquid nitrogen. The histological study showed that embryos subjected to the encapsulation-dehydration, accumulated high sucrose levels which appear to ensure the recovery of the whole embryo after cryopreservation.

Reinstatement of acquisition performance by the presentation of the outcome after extinction in causality judgments.

Two experiments were conducted with the aim of exploring reinstatement after extinction using a causality judgment task in human beings. In Experiment 1, participants learned first that a fictitious medicine produced a side-effect. The medicine was then presented in extinction. Re-exposure to the side-effect by itself before the test reinstated acquisition performance. Reinstatement was greater when exposure took place in the test context than when it took place in a different context. Experiment 2 replicated reinstatement in a situation that ensured equivalent extinction for the different groups before the test.

Trasplante renal ABO incompatible de dador vivo relacionado / ABO incompatible renal transplantation of related living donor

Se presenta un caso, que se suma a recientes y escasos ejemplos comunicados en la literatura extranjera, de un transplante exitoso de un dador de grupo sanguíneo B a un receptor de grupo sanguíneo 0. Se efectuó una preparación previa con esplenectomía, plasmaferesis, corticoides, ciclosporina y globulina antilinfocitaria que, de acuerdo a comunicaciones recientes serían factores determinantes del éxito del trasplante. En casos excepcionales, el trasplante entre grupos ABO incompatibles no debe ser siempre contra-indicado

Trasplante renal ABO incompatible de dador vivo relacionado / ABO incompatible renal transplantation of related living donor

Se presenta un caso, que se suma a recientes y escasos ejemplos comunicados en la literatura extranjera, de un transplante exitoso de un dador de grupo sanguíneo B a un receptor de grupo sanguíneo 0. Se efectuó una preparación previa con esplenectomía, plasmaferesis, corticoides, ciclosporina y globulina antilinfocitaria que, de acuerdo a comunicaciones recientes serían factores determinantes del éxito del trasplante. En casos excepcionales, el trasplante entre grupos ABO incompatibles no debe ser siempre contra-indicado (AU)