Purine nucleoside phosphorylase activity and expression are upregulated in sites affected by periodontal disease.

BACKGROUND AND OBJECTIVE: Purine nucleoside phosphorylase (PNP) is an enzyme that catalyzes the reversible phosphorolysis of purine nucleosides, playing a key role in the purine salvage pathway. Activated T cells seem to rely heavily on PNP to remain functionally active and are particularly sensitive to PNP deficiency. The role of PNP in periodontal tissues has not been characterized thus far. The aim of this study therefore was to assess the activity and expression of PNP in the gingival tissues of periodontitis patients. MATERIAL AND METHODS: Ten patients consecutively admitted for treatment had their periodontal clinical variables recorded and their gingival crevicular fluid collected. After periodontal treatment the patients were seen once a month for plaque and bleeding control, and had their periodontal variables recorded and gingival crevicular fluid collected at 90 and 180 d. Purine nucleoside phosphorylase-specific activity was assessed using a spectrophotometer through the addition of the PNP substrate analog 2-amino-6mercapto-7-methyl purine riboside to the gingival crevicular fluid. In parallel, PNP expression was assessed by immunohistochemistry and real-time PCR in gingival biopsies and cell culture. RESULTS: Purine nucleoside phosphorylase activity was higher in the gingival crevicular fluid of periodontally diseased sites, which was positively correlated with improvements of the clinical variables. Treatment of periodontal disease induced a striking decrease of PNP activity in periodontally diseased sites. Expression of PNP was more pronounced in mononuclear cells and endothelial cells of the gingiva, and the mRNA levels were 5.7-fold higher in inflamed tissues compared with control samples. CONCLUSION: Purine nucleoside phosphorylase activity and expression are upregulated in periodontally diseased sites and can be detected in the gingival crevicular fluid.

[The challenge of teaching how to deliver care from the perspective of the graduation nursing course student]. / Desafio de ensinar a cuidar sob a ótica do aluno do curso de graduação em enfermagem.

This paper refers to teaching/learning in a subject named Fundaments of Human Care III--Care Module--at the Nursing School of the Universidade Federal do Rio Grande do Sul, under the vision of the undergraduate student. In 1996, the subject started at the fourth semester of the curriculum, constituted of its basic thematic, and in which the students learn about the genesis of human care process. The daily reports of the students during this module practice at the Pediatric Oncology Unit (POU) of a University Hospital, in Porto Alegre, RS, were submitted to phenomenological analysis, based on Merleau-Ponty (Martins, 1992). From this analysis emerged the significance expressed by the student of the experiences on the POU; the relation between teaching-practice; theoretical basis and care.