Sarcoma de Ewing extraóseo en la columna dorsal con compresión medular al momento del diagnóstico: Reporte de un caso / Primary extra-osseous Ewing sarcoma of the dorsal spine with spinal cord compression at diagnosis: Case report

Los tumores neuroectodérmicos primitivos a nivel extraóseo son una neoplasia muy rara, con pocas publicaciones en la literatura. Se reporta un caso de una paciente de nueve años quien se presentó con signos de compresión medular. Se estableció un grupo de diagnósticos diferenciales en el abordaje, entre los que debió incluirse la patología oncológica. En la paciente, se observó la presencia de una masa en la columna dorsal con compromiso del cordón medular, que requirió cirugía descompresiva de urgencia y, posteriormente, se diagnosticó sarcoma de Ewing. Cabe resaltar la importancia del caso debido a la baja incidencia del origen extraóseo en esta neoplasia y su rara localización en la columna dorsal, y destacar la presencia de la compresión medular como forma de presentación del cáncer en pediatría, además de la poca información que, hasta el momento, se posee referida al mejor abordaje terapéutico en esta patología, en esta localización.

Extraosseous primitive neuroectodermal tumors are very rare neoplasms. Only a few cases have been published in the literature. This report is about a 9-year-old female patient whose clinical manifestations showed spinal cord compression, so different diagnosis should be considered, including oncology disease. The patient showed a mass of the dorsal spine with spinal cord compression. She was diagnosed with Ewing Sarcoma after surgical intervention and pathology study. It is necessary to highlight the importance of the present case due to the low incidence of the extraosseous Ewing Sarcoma, and its infrequent location at the dorsal spine and the spinal cord compression as initial presentation of pediatric cancer, as well as the poor information related to the best therapeutic strategy to treat this disease at this location.

[Primary extra-osseous Ewing sarcoma of the dorsal spine with spinal cord compression at diagnosis: Case report]. / Sarcoma de Ewing extraóseo en la columna dorsal con compresión medular al momento del diagnóstico: Reporte de un caso.

Extraosseous primitive neuroectodermal tumors are very rare neoplasms. Only a few cases have been published in the literature. This report is about a 9-year-old female patient whose clinical manifestations showed spinal cord compression, so different diagnosis should be considered, including oncology disease. The patient showed a mass of the dorsal spine with spinal cord compression. She was diagnosed with Ewing Sarcoma after surgical intervention and pathology study. It is necessary to highlight the importance of the present case due to the low incidence of the extraosseous Ewing Sarcoma, and its infrequent location at the dorsal spine and the spinal cord compression as initial presentation of pediatric cancer, as well as the poor information related to the best therapeutic strategy to treat this disease at this location.

Los tumores neuroectodérmicos primitivos a nivel extraóseo son una neoplasia muy rara, con pocas publicaciones en la literatura. Se reporta un caso de una paciente de nueve años quien se presentó con signos de compresión medular. Se estableció un grupo de diagnósticos diferenciales en el abordaje, entre los que debió incluirse la patología oncológica. En la paciente, se observó la presencia de una masa en la columna dorsal con compromiso del cordón medular, que requirió cirugía descompresiva de urgencia y, posteriormente, se diagnosticó sarcoma de Ewing. Cabe resaltar la importancia del caso debido a la baja incidencia del origen extraóseo en esta neoplasia y su rara localización en la columna dorsal, y destacar la presencia de la compresión medular como forma de presentación del cáncer en pediatría, además de la poca información que, hasta el momento, se posee referida al mejor abordaje terapéutico en esta patología, en esta localización.

II - Insulin processing in mitochondria.

Our objective was to know how insulin is processing in mitochondria; if IDE is the only participant in mitochondrial insulin degradation and the role of insulin degradation on IDE accumulation in mitoplasts. Mitochondria and its fractions were isolated as described by Greenwalt. IDE was purified and detected in immunoblot with specific antibodies. High insulin degradation was obtained through addition to rat's diet of 25 g/rat of apple and 10 g/rat of hard-boiled eggs, 3 days a week. Mitochondrial insulin degradation was assayed with 5 % TCA, insulin antibody or Sephadex G50 chromatography. Degradation was also assayed 60 min at 37 °C in mitochondrial fractions (IMS and Mx) with diet or not and without IDE. Degradation in fractions precipitated with ammonium sulfates (60-80 %) were studied after mitochondrial insulin incubation (1 ng. insulin during 15 min, at 30 °C) or with addition of 2.5 mM ATP. Supplementary diet increased insulin degradation. High insulin did not increase mitoplasts accumulation and did not decrease mitochondrial degradation. High insulin and inhibition of degradation evidence insulin competition for a putative transport system. Mitochondrial incubation with insulin increased IDE in matrix as observed in immunoblot. ATP decreased degradation in Mx and increased it in IMS. Chromatography of IMS demonstrated an ATP-dependent protease that degraded insulin, similar to described by Sitte et al. Mitochondria participate in insulin degradation and the diet increased it. High insulin did not accomplish mitochondrial decrease of degradation or its accumulation in mitoplasts. Mitochondrial incubation with insulin increased IDE in matrix. ATP suggested being a regulator of mitochondrial insulin degradation.

Viroids, the simplest RNA replicons: How they manipulate their hosts for being propagated and how their hosts react for containing the infection.

The discovery of viroids about 45 years ago heralded a revolution in Biology: small RNAs comprising around 350 nt were found to be able to replicate autonomously-and to incite diseases in certain plants-without encoding proteins, fundamental properties discriminating these infectious agents from viruses. The initial focus on the pathological effects usually accompanying infection by viroids soon shifted to their molecular features-they are circular molecules that fold upon themselves adopting compact secondary conformations-and then to how they manipulate their hosts to be propagated. Replication of viroids-in the nucleus or chloroplasts through a rolling-circle mechanism involving polymerization, cleavage and circularization of RNA strands-dealt three surprises: (i) certain RNA polymerases are redirected to accept RNA instead of their DNA templates, (ii) cleavage in chloroplastic viroids is not mediated by host enzymes but by hammerhead ribozymes, and (iii) circularization in nuclear viroids is catalyzed by a DNA ligase redirected to act upon RNA substrates. These enzymes (and ribozymes) are most probably assisted by host proteins, including transcription factors and RNA chaperones. Movement of viroids, first intracellularly and then to adjacent cells and distal plant parts, has turned out to be a tightly regulated process in which specific RNA structural motifs play a crucial role. More recently, the advent of RNA silencing has brought new views on how viroids may cause disease and on how their hosts react to contain the infection; additionally, viroid infection may be restricted by other mechanisms. Representing the lowest step on the biological size scale, viroids have also attracted considerable interest to get a tentative picture of the essential characteristics of the primitive replicons that populated the postulated RNA world.

Cell-to-cell and systemic movement of recombinant green fluorescent protein-tagged turnip crinkle viruses.

To facilitate analyses of turnip crinkle virus (TCV) cell-to-cell and systemic movement, we created a series of recombinant viruses expressing green fluorescent protein (GFP) either as substitutions of coat protein (CP) sequences or as fusions to movement proteins (MPs). Constructs were used to inoculate leaves of Arabidopsis seedlings. TCV carrying its two native MPs and GFP fused near the start of CP translation (GFP DeltaCP) resulted in cell-to-cell movement manifested by the expansion of fluorescent foci on inoculated leaves. GFP fusions to either MP were inactive for movement. However, TCV carrying the p9-GFP fusion, which expresses a functional p8 gene, could be complemented for cell-to-cell movement by coinoculation with virus carrying native p9 but mutant for p8. This same coinoculation combination also lead to systemic spread of GFP fluorescence to noninoculated leaves, as the complementing virus carries native CP. Complementation for systemic movement of virus carrying GFP DeltaCP constructs was achieved by inoculation onto transgenic plants expressing TCV CP. GFP-tagged TCV movement was detected throughout the plant, including the inflorescence stem, cauline leaves, flowers, siliques, and substructures such as organ primordia and meristematic regions. The recombinant viruses described herein provide (1) genetic information relevant to define regions of TCV that can, or cannot, be manipulated by insertion of foreign coding sequences and (2) a set of tools to allow the study of viral cell-to-cell and long-distance movement in the model plant system Arabidopsis.

Nuclear localization of turnip crinkle virus movement protein p8.

Turnip crinkle virus (TCV) is a single-stranded positive-sense RNA virus of the Carmovirus genus. Two of its five open reading frames (ORFs), encoding proteins of 8 and 9 kDa, are required for cell-to-cell movement of the virus. These movement proteins (MPs) were fused to green fluorescent protein (GFP) to determine their cellular localization. In protoplasts, p9-GFP, like GFP itself, is found throughout the cytoplasm, as well as in cell nuclei. In contrast, p8-GFP was confined to the cell nucleus. Similar localization patterns were observed when specific small peptide epitopes were fused to p8 and p9 proteins instead of GFP. The cytoplasmic localization of p9-GFP and nuclear localization of p8-GFP were also detected in leaves after particle bombardment of DNA encoding these fusion proteins or after overexpression of p8-GFP in transgenic Arabidopsis seedlings. The expression of the GFP fusion proteins by recombinant TCV viruses in infected protoplasts or on inoculated Arabidopsis leaves produced similar patterns. Unlike TMV-MP and other MPs studied to date, no obvious punctuate expression in the cell wall or association with the cytoskeleton was detected. The sequence analysis of p8 revealed two unique nuclear localization signals (NLSs), which were not conserved within p8 homologues of other viruses in the genus Carmovirus. Mutation in either of these NLSs did not disrupt the nuclear localization of p8-GFP. However, when both NLSs were mutated, p8-GFP expression was no longer restricted to cell nuclei. The NLSs are not required for cell-to-cell movement; TCV recombinant viruses mutated in one or both NLSs could still facilitate cell-to-cell movement of the virus. The nuclear localization of p8 suggests a novel function for this protein in the cell nucleus.

Temporal and spatial regulation of symplastic trafficking during development in Arabidopsis thaliana apices.

Plasmodesmata provide symplastic continuity linking individual plant cells. However, specialized cells may be isolated, either by the absence of plasmodesmata or by down regulation of the cytoplasmic flux through these channels, resulting in the formation of symplastic domains. Maintenance of these domains may be essential for the co-ordination of growth and development. While cells in the center of the meristem divide slowly and remain undifferentiated, cells on the meristem periphery divide more frequently and respond to signals determining organ fate. Such symplastic domains were visualized within shoot apices of Arabidopsis, by monitoring fluorescent symplastic tracers (HPTS: 8-hydroxypyrene 1,3,6 trisulfonic acid and CF: carboxy fluorescein). Tracers were loaded through cut leaves and distributed throughout the whole plant. Confocal laser scanning microscopy on living Arabidopsis plants indicates that HPTS moves via the vascular tissue from leaves to the apex where the tracer exits the phloem and moves symplastically into surrounding cells. The distribution of HPTS was monitored in vegetative apices, and just prior to, during, and after the switch to production of flowers. The apices of vegetative plants loaded with HPTS had detectable amounts of tracer in the tunica layer of the meristem and in very young primordia, whereas the corpus of the meristem excluded tracer uptake. Fluorescence signal intensity decreased prior to the onset of flowering. Moreover, at approximately the time the plants were committed to flowering, HPTS was undetectable in the inflorescence meristem or young primordia. Later in development, after several secondary inflorescences and mature siliques appeared, inflorescence apices again showed tracer loading at levels comparable to that of vegetative apices. Thus, analysis of fluorescent tracer movement via plasmodesmata reveals there is distinct temporal and spatial regulation of symplastic domains at the apex, dependent on the developmental stage of the plant.

Chitin oligosaccharides can induce cortical cell division in roots of Vicia sativa when delivered by ballistic microtargeting.

Rhizobia, bacterial symbionts of leguminous plants, produce lipo-chitin oligosaccharide (LCO) signal molecules that can induce nodule organogenesis in the cortex of legume roots in a host-specific way. The multi-unsaturated fatty acyl and the O-acetyl moieties of the LCOs of Rhizobium leguminosarum biovar viciae were shown to be essential for obtaining root nodule induction in Vicia sativa plants. We have used ballistic microtargeting as a novel approach to deliver derivatives of the nodulation signal molecules inside the roots of V. sativa. This method offers the unique ability to introduce soluble compounds into the tissue at a small area. The mitogenic effect of microtargeting of chitin oligosaccharides, including an analysis of the influence of the chain length and modifications, was tested in a qualitative assay. The role of a cell division factor from the root stele, uridine, has also been examined in these experiments. The results show that O-acetylated chitin oligosaccharides can induce root cortical cell divisions when delivered by microtargeting. For this effect it is essential that uridine is co-targeted. The foci of cortical cell division were often similar to root nodule primordia. Anatomical examination also revealed chimeric structures that share characteristics with lateral root and nodule primordia. Our data favour a model in which the oligosaccharide moiety of the rhizobial LCO induces cortical cell division and the fatty acyl moiety plays a role in transport of the LCO into the plant tissue.

In vivo observation of large foreign DNA molecules in host plant cells.

We have developed a system to monitor microscopically the fate of foreign DNA within plant cells in vivo. Fluorescein-11-dUTP was used to label DNA during target-specific amplification by polymerase chain reaction (PCR). Labeled DNA fragments of 1.5-3.5 kb were prepared and then transported into tobacco protoplasts by polyethylene glycol (PEG)-mediated direct gene transfer. We localized the foreign, labeled DNA within the cell by confocal laser scanning microscopy.

In vitro germination of wheat proembryos to fertile plants.

Wheat proembryos were excised 7 days after anthesis and germinated to normal fertile plants with an efficiency of 90%. These embryos had clearly differentiated shoot apical meristems and represent an interesting model system for studies of meristem biology. A combination of two media with different osmolarities allowed the continued development of the embryos before induction of germination. Normal germination occurred only after the first leaf primordium had already covered the shoot apical meristem.