ABSTRACT
The corpus callosum is a large fiber tract that connects neurons in the right and left cerebral hemispheres. Agenesis of the corpus callosum (ACC) is associated with a large number of human syndromes but little is known about why ACC occurs. In most cases of ACC, callosal axons are able to grow toward the midline but are unable to cross it, continuing to grow into large swirls of axons known as Probst bundles. This phenotype suggests that in some cases ACC may be due to defects in axonal guidance at the midline. General guidance mechanisms that influence the development of axons include chemoattraction and chemorepulsion, presented by either membrane-bound or diffusible molecules. These molecules are not only expressed by the final target but by intermediate targets along the pathway, and by pioneering axons that act as guides for later arriving axons. Midline glial populations are important intermediate targets for commissural axons in the spinal cord and brain, including the corpus callosum. The role of midline glial populations and pioneering axons in the formation of the corpus callosum are discussed. Finally the differential guidance of the ipsilaterally projecting perforating pathway and the contralaterally projecting corpus callosum is addressed. Development of the corpus callosum involves the coordination of a number of different guidance mechanisms and the probable involvement of a large number of molecules
Subject(s)
Animals , Humans , Axons , Corpus Callosum , Neuroglia , Perforant Pathway , Cell Differentiation , Corpus Callosum , Glial Fibrillary Acidic ProteinABSTRACT
Cancrum oris (noma) has been most commonly described in malnourished debilitated children with poor oral hygiene following systemic childhood infections such as measles, pertussis or scarlet fever. We describe a patient who developed this condition during a period of profound neutropenia following cytotoxic chemotherapy for acute lymphoblastic leukaemia.
Subject(s)
Humans , Female , Adult , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Neutropenia/chemically induced , Noma/chemically induced , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Gangrene , Remission Induction , Staphylococcal Infections/chemically induced , Staphylococcal Infections/pathology , Klebsiella Infections/chemically induced , Klebsiella Infections/pathology , Pseudomonas Infections/chemically induced , Pseudomonas Infections/pathology , Klebsiella pneumoniae , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/pathology , Lip/pathology , Mouth Mucosa/pathology , Neutropenia/pathology , Noma/pathology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Pseudomonas aeruginosaABSTRACT
Este trabajo presenta el problema que representa la desnutrición primaria en edad pediátrica y sus implicaciones en el posterior desarrollo del niño. Revisaremos la epidemiología, fisiopatología, cuadro clínico y el tratamiento de afección; haremos énfasis en la prevención por su importancia en la solución del problema