RESUMEN
The primitive neuroectodermal tumor of the central nervous system is one of a number of tumors in which deletions on chromosome 17p have been identified. The tumor suppressor gene, p53, is located in the region of the deletion. To determine if the p53 gene is involved in the development of primitive neuroectodermal tumors, deoxyribonucleic acid (DNA) blot analysis, ribonucleic acid blot analysis, and p53 complementary DNA sequencing were performed on 34 primitive neuroectodermal tumors removed from children. No rearrangement in the gene was detected in 21 tumors. The p53 messenger ribonucleic acid was of the expected size in all 18 tumors for which ribonucleic acid was available. Sequencing of p53 Exons 5 through 9 revealed a mutation in the cell line DAOY and in only 1 of 14 tumors examined. A DNA rearrangement was detected in the DNA from one tumor with a probe mapping to the distal portion of 17p. Taken together, these data suggest that the p53 gene is not involved in the development of most primitive neuroectodermal tumors. In addition, a gene of interest may be present on distal 17p.
Asunto(s)
Neoplasias del Sistema Nervioso Central/genética , Neoplasias de Células Germinales y Embrionarias/genética , Proteína p53 Supresora de Tumor/genética , Adolescente , Adulto , Encéfalo/patología , Neoplasias del Sistema Nervioso Central/patología , Neoplasias del Sistema Nervioso Central/cirugía , Niño , Preescolar , Aberraciones Cromosómicas/genética , Cromosomas Humanos Par 16 , Terapia Combinada , Sondas de ADN , Femenino , Humanos , Lactante , Masculino , Mutación , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/cirugía , Neoplasias de Células Germinales y Embrionarias/patología , Neoplasias de Células Germinales y Embrionarias/cirugía , Reacción en Cadena de la Polimerasa , Médula Espinal/patologíaAsunto(s)
Astrocitoma/cirugía , Neoplasias de la Médula Espinal/cirugía , Adulto , Humanos , PronósticoRESUMEN
Considerable controversy currently exists with respect to whether or not local anaesthetics exert direct action on cerebral arteriolar tone. In situ experiments were therefore undertaken on pial terminal arterioles of rats to determine whether or not perivascular application of lidocaine exerts any action on such cerebral vessels. Vessel size was assessed with an image-splitting television microscope recording system. The vessels studied ranged in size from 25 to 30 micron. Lidocaine was applied in artificial CSF in dosages of 0.01, 0.1, 1.0 and 2.0 mg. Significant dose-dependent dilatation (i.e., 15.7-45.3% increases in lumen sizes) of the pial terminal arterioles was observed. The results are discussed in light of current developments concerning the mechanism whereby local anaesthetics alleviate increased intracranial pressure and cerebral vasospasm.
Asunto(s)
Anestésicos Locales/farmacología , Lidocaína/farmacología , Piamadre/irrigación sanguínea , Animales , Arteriolas/efectos de los fármacos , Circulación Cerebrovascular/efectos de los fármacos , Masculino , Microcirculación/efectos de los fármacos , RatasRESUMEN
The effects of local perivascular application of dopamine to rat pial arterioles. (20-40 micrometer i.d.) were examined in situ, at the microcirculatory level, by use of a high-resolution closed circuit television microscope recording system. Local application of very low, physiological doses (1 to 10 pg) of dopamine to pial arterioles of the anaesthetized rat induces vasodilatation, whereas higher doses induce vasoconstriction. The magnitudes of these biphasic responses obtained in male rats were not significantly different from those obtained in female animals. Our findings support the theory that local release of this neurotransmitter amine from perivascular cells in the brain may promote local increases in cerebral blood flow.