The behavior of sex chromosomes in two human X-autosome translocations: failure of extensive X-inactivation spreading

Two patients, one adult male and one infant girl, bearing different X-autosome translocations, were studied with cytogenetical, ultrastructural and chromosome-painting techniques. The adult male, is a carrier of a reciprocal, balanced translocation involving the X and #2 chromosomes: 46,Y,t(X;2) (q13;p21). This man showed infertility with spermatogenesis arrest at the spermatocyte stage. Synaptonemal complex analysis at pachytene showed the quadrivalent structure and the putative breakage points. Sex-chromatin condensation did not spread towards the autosomal regions of the quadrivalent. The female infant showed diminished body growth and multiple somatic anomalies. She is a 45,Xp-,t(X;21)(p11;p13) carrier, an unbalanced translocation involving chromosomes X and #21, which leads to a monosomy of almost all Xp. The translocated #21 is practically complete, and its centromere is the active one in the rearranged product. The analysis of interphase nuclei with the X-centromere probe shows that the Xq region of the rearranged chromosome is the late -replicating and inactive element. However, X-inactivation does not spread to the attached #21, as shown by the R-banding pattern. Thus, both in the male adult and in the female infant there is a barrier to the spreading effect of X-chromosome inactivation, which is probably due to different mechanisms.

Nutrición parenteral total en ausencia de función renal para el tratamiento de complicaciones de la cirugía gastrointestinal / Total parenteral nutrition in terminarl renal failure for the treatment of complications of gastrointestinal surgery

Este es un reporte preliminar sobre una niña de ocho años con ausencia de función renal, en diálisis crónica, que desarrolló una fístula de intestino delgado post-operatoria a débido alto, asociada a sepsis y desnutrición. La paciente tuvo un tratamiento con resultado exitoso al utilizar un esquema de Nutrición Parenteral Total que incluía una solución de aminoácidos que contenia 60 por ciento de amnoácidos esenciales y un 40 por ciento de aminoácidos no esenciales, ahora disponible en el Perú, sin tener que aumentar la frecuencia de hemodiálisis por un período de 72 días en Nutrición Parenteral Total. Se resalta el manejo por una Unidad de Soporte Nutrional Artificial.