Browsing by Author "Sandoval, P"

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    Intra-arterial thrombolysis in locked-in syndrome. Report of two cases
    (SOC MEDICA SANTIAGO, 2004) Mellado, P; Sandoval, P; Tevah, J; Huete, I; Castillo, L
    Locked-in syndrome is a dramatic clinical condition, the patient is can listen. and breath, but is unable to move any muscle, conserving only The vertical eye movements. The most common cause of locked-in syndrome is the thrombosis of the basilar artery and commonly leads to death, frequently due to pneumonia. Intravenous and intra arterial thrombolysis have been used successfully in a selective group of patients with ischemic stroke. There is only one report of two patients with locked-in syndrome who were treated successfuly with intra arterial thrombolysis. Other authors, based in their experiences, do not recommended this treatment. We report two female patients aged 63 and 26 years, with Locked-in syndrome due to a basilar thrombosis who were treated successfully with intra arterial thrombolysis using ecombinant tissue plasminogen activator (r-TPA). The lapses between the onset of the symptoms and thrombolysis were 5 and 8 hours respectively. A complete recanalization was obtained in both patients during the thrombolysis. One year after, the first patient has only a moderate ataxia, walking with assistance and the other has a normal neurological examination (Rev Med Chile 2004; 132: 357-60).
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    Reversible nitrous oxide myelopathy and a polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase
    (2006) Lacassie, HJ; Nazar, C; Yonish, B; Sandoval, P; Muir, HA; Mellado, P
    We present a case of a patient who received nitrous oxide on two occasions within a period of 8 weeks and who subsequently developed a diffuse myelopathy, characterized by upper extremity paresis, lower extremity paraplegia and neurogenic bladder. Laboratory testing revealed hyper-homocysteinaemia and low levels of vitamin B-12. Because of this uncommon clinical presentation, we analysed the patient's DNA, and found a polymorphism in the MTHFR gene that is associated with the thermolabile isoform of the 5,10-methylenetetrahydrofolate reductase enzyme, which explained the myelopathy experienced by the patient after being exposed to nitrous oxide. Soon after initiating supplementary therapy with folic acid and vitamin B12, the neurological symptoms subsided.
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    Transfer of RPS14 and RPL5 from the mitochondrion to the nucleus in grasses
    (2004) Sandoval, P; León, G; Gómez, I; Carmona, R; Figueroa, P; Holuigue, L; Araya, A; Jordana, X
    Gene transfer from the mitochondrion to the nucleus, a process of outstanding importance to the evolution of the eukaryotic cell, is an ongoing phenomenon in higher plants. After transfer, the mitochondrial gene has to be adapted to the nuclear context by acquiring a new promoter and targeting information to direct the protein back to the organelle. To better understand the strategies developed by higher plants to transfer organellar genes during evolution, we investigated the fate of the mitochondrial PPL5-RPS14 locus in grasses. While maize mitochondrial genome does not contain RPS14 and RPL5 genes, wheat mitochondrial DNA contains an intact RPL5 gene and a nonfunctional RPS14 pseudogene. RPL5 and psiRPS14 are co-transcribed and their transcripts are edited. In wheat, the functional RPS14 gene is located in the nucleus, within the intron of the respiratory complex II iron-sulfur subunit gene (SDH2). Its organization and expression mechanisms are similar to those previously described in maize and rice, allowing us to conclude that RPS14 transfer and nuclear activation occurred before divergence of these grasses. Unexpectedly, we found evidence for a more recent RPL5 transfer to the nucleus in wheat. This nuclear wheat RPL5 acquired its targeting information by duplication of an existing targeting presequence for another mitochondrial protein, ribosomal protein L4. Thus, mitochondrial and nuclear functional RPL5 genes appear to be maintained in wheat, supporting the hypothesis that in an intermediate stage of the transfer process, both nuclear and mitochondrial functional genes coexist. Finally, we show that RPL5 has been independently transferred to the nucleus in the maize lineage and has acquired regulatory elements for its expression and a mitochondrial targeting peptide from an unknown source. (C) 2003 Elsevier B.V. All rights reserved.