Biomedical subjects
Publications and source records attributed to Ricardo N Laurini.
The authors describe a 9-year-old boy who had an accident with his bicycle. He presented with hematuria a few weeks later, and cystoscopy results showed a polypod lesion near the veru montanum. The lesion was resected, and histologic examination showed a nephrogenic adenoma (NA), which recurred 6 years later with hematuria. NA is a rare lesion in a child's urethra and can be a source of hematuria.
OBJECTIVE: To investigate associations between structural, functional and circulatory placental changes in pregnancies complicated by impaired glucose metabolism. DESIGN: Umbilical artery (UA) blood flow resistance was measured by Doppler velocimetry in 21 gravidae with diabetes/impaired glucose tolerance (IGT) and 10 healthy gravidae. Umbilical and placental vessel segments were incubated for determination of prostacyclin and thromboxane synthesis, and tissues histologically examined. Non-parametric statistical tests at a two-tailed P<0.05 were used. RESULTS: Placental lesions were more common in diabetes/IGT and, although not being an uniform finding, in general associated with a higher vascular synthesis of thromboxane and/or lower prostacyclin/thromboxane synthesis ratio. As an exception, ischemic villitis was associated with a higher ratio and higher UA flow resistance. CONCLUSIONS: Placental lesions are associated with an altered vascular prostanoid synthesis in diabetes/IGT, but not until structural signs of ischemia develop is a rise of UA blood flow resistance detected.
The peroxisome proliferator activated receptors (PPARs) are ligand activated receptors which belong to the nuclear hormone receptor family. As with other members of this superfamily, it is thought that the ability of PPAR to bind to a ligand was acquired during metazoan evolution. Three different PPAR isotypes (PPARalpha, PPARbeta, also called 6, and PPARgamma) have been identified in various species. Upon binding to an activator, these receptors stimulate the expression of target genes implicated in important metabolic pathways. The present article is a review of PPAR expression and involvement in some aspects of Xenopus laevis and rodent embryonic development. PPARalpha and beta are ubiquitously expressed in Xenopus early embryos but become more tissue restricted later in development. In rodents, PPARalpha, PPARbeta and PPARgamma show specific time- and tissue-dependent patterns of expression during fetal development and in the adult animals. PPARs are implicated in several aspects of tissue differentiation and rodent development, such as differentiation of the adipose tissue, brain, placenta and skin. Particular attention is given to studies undertaken by us and others on the implication of PPARalpha and beta in rodent epidermal differentiation.