[Language and aphasias]. / Lenguaje y afasias.

INTRODUCTION AND OBJECTIVE: Approximately 400,000 years ago men started to use language. Initially it was probably poor with few phonemes. With social evolution it became more complex, with the appearance of new phonemes and a more complete grammatical structure. The current concept of the processing of language dates, with little change, from the nineteenth century. DEVELOPMENT: With the birth of phrenology language began to be studied. This lead to the hypothesis of Wernicke, with two main areas joined by the fasciculo arcuato, which is still held to be valid with modifications by Gerchwind and Damasio, amongst others. Important advances in the study of language are due to Chomsky and his transformational grammar. This supports the universal structure of language, since one learns it following genetically determined laws. Language has three main aspects: creativity which makes both the transmitter and the receiver active participants in communication, the form from which words are constructed and the content of the message. Aphasia is an alteration in the comprehension and understanding of language, which may be the clinical expression of many different aetiologies. They help us to localize the lesion topographically. They are divided depending on the clinical signs, into motor or Broca's aphasia, in which understanding is conserved but the patient uses a language with poor grammatical structure, although the semantic content is acceptable: sensitive or Wernicke's aphasia, with inability to understand and language which is fluid but unintelligible; conduction aphasia due to limitation in the transmission of impulses from Wernicke's area to that of Broca, with acceptable understanding and fluid language and the trans-cortical aphasias where the main characteristic is indemnity of the capacity of repetition. CONCLUSIONS: The aphasias, as the expression of an alteration of language are an important support in the topographical localization of lesions, even before these can be shown on computerized tomography.

Light induction of gene expression in Myxococcus xanthus.

The synthesis of carotenoids by Myxococcus xanthus requires illumination with blue light. Mutations at two loci (carA and carR) remove the blue-light requirement and cause constitutive production of carotenoids. Mutations at a different locus (carB) prevent carotenogenesis in both wild-type and constitutive mutant strains. We describe here three independent car mutations induced by insertion of Tn5 lac, a transposon that carries a transcriptional probe for exogenous promoters. All three transposon insertions block carotenogenesis even in constitutive mutant strains. One insertion is in a previously unknown car gene and the other two are in the carB locus. One of the carB insertions expresses beta-galactosidase at very low levels in the dark but is strongly activated by light. When this Tn5 lac insertion is introduced in carA or carR mutants it expresses beta-galactosidase in dark- as well as light-grown cells. We conclude that carotenogenesis in M. xanthus is activated at the level of transcription by a light-induced mechanism in which the carA and the carR loci (or their gene products) take part. The potential usefulness of M. xanthus as a simple and sensitive tool for studies in photobiology is discussed.

Accumulation of carotenoids in structural and regulatory mutants of the bacterium Myxococcus xanthus.

Accumulation of carotenoids in Myxococcus xanthus is absolutely dependent on illumination with blue light. We report the analysis of the carotenoids of dark- and light-grown cultures of the wild type and several previously characterized mutants. A carR mutant produces the same carotenoids in the dark as the wild type grown in the light. This agrees with previous evidence indicating that the carR gene codes for a general negative regulator of the system. A cis-dominant mutation in the gene carA causes constitutive expression of the light-inducible gene carB, which is linked to carA. In the dark, the carA mutant produces high levels of phytoene, the first C40 colourless carotenoid precursor; in the light, it produces the same carotenoids as the wild type. Since a mutation in carB blocks accumulation of phytoene, we propose that carB, and probably other linked genes also controlled by carA, code for enzymes involved in the synthesis of phytoene. This is virtually the only carotene accumulated by strains mutated in the gene carC, which is unlinked to the others. Thus carC codes for phytoene dehydrogenase, the enzyme that converts phytoene into coloured carotenoids. The results presented here also provide evidence for control of carotenogenesis by an endproduct that is independent of the blue light effect.

Bronquiolitis obliterante con neumonía organizada en un paciente con artritis reumatoide / Bronchiolitis obliterans with organizing pneumonia associated with rheumatoid arthritis

Presentamos un paciente con artritis reumatoide de larga evolución que ingresa por cuadro sugerente de infección respiratoria. Teniendo en cuenta su enfermedad de base y que en ese momento está en tratamiento con metotrexato, se plantea el diagnóstico diferencial entre afectación pulmonar asociada a artritis reumatoide o secundaria a toxicidad farmacológica. El paciente es diagnosticado finalmente de bronquiolitis obliterante con neumonía organizada en relación con artritis reumatoide, entidad poco frecuente de la que hemos encontrado escasas descripciones en la literatura revisada (AU)