ABSTRACT
Se presenta una revisión bibliográfica relacionada con la funcionalidad de la matriz extracelular y sus distintos componentes en el sentido de gatillar y modular el proceso biológico de la diferenciación celular, con especial énfasis en los diferentes fenotipos adquiridos por las células pertenecientes al epitelio mamario de ratas mantenido en cultivo, como resultado de la inducción al proceso de diferenciación tanto en ausencia como en presencia de constituyentes de dicha matriz.
Subject(s)
Animals , Male , Female , Adult , Rats , Mammary Glands, Animal/anatomy & histology , Mammary Glands, Animal , Extracellular Matrix/physiology , Extracellular Matrix/ultrastructure , Epithelioid Cells/cytology , Cell DifferentiationABSTRACT
The pineal gland of Akodon arviculoides cursor shows a saccular pattern of organization with a wide and irregular lumen outlined by cuboidal and columnar epithelial cells. This feature was never reported before, in literature, among mammals. the pinealocytes are clustered together in the periphery of the organ and can be distinguished as light and dark cells. These cells show great amounts of mitochondria, microtubules, polysomes and a few dense-core vesicles. Higher amounts of dense-core vesicles are present in pinealocytes of young animals than in adult ones. In spite of the sacccular and follicular patterns of organization, that are considered a more primitive aspect of the gland, we could not observe, in this species, outer segments in the pinealocytes, which characterize the photoreceptor cells of the pineal organ in lower vertebrates.
Subject(s)
Animals , Adult , Epithelioid Cells/cytology , Cytoplasm , Pineal Gland , Cytological Techniques/standardsABSTRACT
OBJECTIVE: To determine the clinical, biochemical, ultrasonological and cytomorphological features in goitrous juvenile chronic lymphocytic thyroiditis(CLT). SETTING: Tertiary referral center for thyroid disorders. SUBJECTS: A total of 455 children were evaluated for goiter. Of these 122 children had features of CLT in FNAC and were further studied. METHODS: All subjects were subjected to detailed clinical examination. The thyroid functional status was assessed by estimation of serum concentration of thyroid hormones (thyroxine and triiodothyronine) and thyrotropin (TSH). In addition the antithyroid antibody titers were measured. Ultrasonological and cytomorphological characteristics in these patients were also evaluated. RESULTS: The mean age at presentation was 12.5 years (SD 3.93). The male: female ratio was 1:7.7. Thyroid functional status as assessed by serum thyroxine and thyrotropin levels revealed, euthyroidism in 67 (54.9%), hypothyroidism in 30 (24.6%), subclinical hypothyroidism in 22 (18%) and hyperthyroidism in 3 (2.5%). Thyroid antimicrosomal antibodies were detected in significant titers in 90 (73.8%) and antithyroglobulin was positive in 71 (58.2%). The positivity of the antimicrosomal and antithyroglobulin antibodies were much higher in subjects with hypothyroidism and was detected in 86.5% and 69.2%, respectively. The mean urinary iodine excretion was 74.1 micrograms/g of creatinine (SD 31.4) indicating mild iodine deficiency. Fine needle aspiration cytoloty (FNAC) revealed features of chronic lymphocytic thyroiditis. Hurthle cell changes was seen in only 12% of the cases. The epithelium was more often hyperplastic and vacuolation of the cytoplasm and peripheral vacuolations were seen frequently. Giant cells and epithelioid cells were seen in many cases. CONCLUSIONS: In any child presenting with firm goiter, a diagnosis of CLT should be excluded. Many subjects with juvenile CLT have biochemical evidence of hypothyroidism but only few symptoms or clinical features.