RESUMO
Objective: To examine the effects of prenatal administration of retinoic acid on the proliferation of epithelioreticular cells and Hassall's corpuscles in the medulla of chick thymus
Study Design: Experimental study
Place and Duration of Study: Anatomy Department, College of Physicians and Surgeons Pakistan [CPSP] Regional centre, Islamabad, from February 2009 to February 2010
Materials and Methods: A total of 120, fertilized chicken eggs were divided into an experimental group A, and its control group B. Group A was injected with retinoic acid via yolk sac on day zero of incubation. Group B was sham injected with saline. Subgroup A1 and B1 were incubated till embryonic day 15 and subgroups A2 and B2 were incubated till hatching. The number of epithelioreticular cells and Hassall's corpuscles were counted. Diameter of Hassall's corpuscles was measured. The parameters were compared statistically between the experimental and control groups
Results: The number of epithelioreticular cells was significantly less than the control group at embryonic stage [p=0.009] as well as at hatching [p=0.001]. The number of Hassall's corpuscles was not different between the embryonic groups but was considerably more than the control in the experimental group at hatching [p=0.01]. The diameter of the Hassall's corpuscles belonging to the experimental groups was significantly different than the age matched control groups at the embryonic stage [p=0.004] as well as at hatching [p=0.008]
Conclusion: Prenatal exposure to retinoic acid significantly reduced the number of epithelioreticular cells and increased the size and the number of the Hassall's corpuscles
RESUMO
Mucopolysaccharidosis [MPS] are a group of metabolic disorders of the lysosomal storage disease family caused by the absence or malfunctioning of lysosomal enzymes, which blocks degradation of mucopolysaccharides and leads to abnormal accumulation of heparan sulfate, dermatan sulfate, and keratan sulfate. Morquio's syndrome is a rare autosomal-recessive mucopolysaccharidosis. This syndrome is characterized by a reduced activity of N-acetylgalactosamine-6-sulfate-sulfatase [type A], or beta-galactosidase [type B]. This deficiency leads to a lysosomal storage disease with accumulation of keratan sulfate and chondroitin-6-sulfate in connective tissue, skeletal system and teeth. The general phenotype includes coarse facies, corneal clouding, hepatosplenomegaly, joint stiffness, hernias, dysostosis multiplex, lower limb alignment problems, mucopolysaccharides excretion in the urine and metachromatic staining in peripheral leukocytes and bone marrow. Consequently, aortic valvular disease, gastrointestinal disease and dental abnormalities occur. Clinical manifestations of mucopolysaccharidosis depend on the type of disease. We report a case of morquio's syndrome in a child, solely diagnosed on the basis of history and physical examination of the case reported. The clinical features and complications of the case and review of the literature are discussed