Interferon‐γ, Interleukins‐6 and ‐4, and Factor XIII‐A as Indirect Markers of the Classical and Alternative Macrophage Activation Pathways in Chronic Periodontitis

Background: Macrophages account for 5% to 30% of the inflammatory infiltrate in periodontitis and are activated by the classic and alternative pathways. These pathways are identified by indirect markers, among which interferon (IFN)‐γ and interleukin‐6 (IL)‐6 of the classic pathway and IL‐4 of the alternative pathway have been studied widely. Recently, factor XIII‐A (FXIII‐A) was reported to be a good marker of alternative pathway activation. The aim of this study is to determine the macrophage activation pathways involved in chronic periodontitis (CP) by the detection of the indirect markers IFN‐γ, IL‐6, FXIII‐A, and IL‐4. Methods: Biopsies were taken from patients with CP (n = 10) and healthy individuals (n = 10) for analysis of IFN‐γ, IL‐6, IL‐4, and FXIII‐A by Western blot (WB), immunohistochemistry (IHC), and enzyme‐linked immunosorbent assay (ELISA). The same biopsies of healthy and diseased gingival tissue were used, and the expressions of these markers were compared between healthy individuals and those with CP. Results: The presence of macrophages was detected by CD68+ immunohistochemistry and their IFN‐γ, IL‐6, IL‐4, and FXIII‐A markers by WB, IHC, and ELISA in all samples of healthy and diseased tissue. IL‐6, IL‐4, and FXIII‐A were significantly higher in patients with CP, whereas FXIII‐A was higher in healthy individuals. Conclusion: The presence of IFN‐γ, IL‐6, IL‐4, and FXIII‐A in healthy individuals and in patients with CP suggests that macrophages may be activated by both classic and alternative pathways in health and in periodontal disease.     

Epidemiology of migraine

One-year migraine prevalence rates in the general population for Western countries vary from 4% to 9% in men and from 11% to 25% in women. Non-Western countries report lower figures. Incidence rates for people under 30 years of age vary from 1.5 to 6 per 1000 person-years in men and from 3 to 24 per 1000 person-years in women. Data on the prevalence of migraine in general, on the gender ratio and on the variations in prevalence in the different age ranges are fairly comparable and can be regarded as very close to reality. On the contrary, data on the incidence of migraine, on the prevalence of different migraine subtypes, such as migraine with aura and the so-called migrainous disorder, and on the frequency of migraine attacks show a striking discordance that somewhat undermines their reliability. The main critical points in prevalence and incidence studies are migraine definition and the methodological approaches used for case screening. Even if International Headache Society (IHS) classification is certainly an improvement over previous tools used in epidemiological studies, the diagnostic criteria for migraine without aura are quite scanty and not easily remembered by subjects belonging to the general population, and those for migraine with aura appear not only difficult to translate for use in a questionnaire or an interview, but also too loose. In particular, the lack of any low-end limit for aura duration may cause an overestimation of migraine with aura prevalence.     

Selective Cumulative Inhibition of Platelet Thromboxane Production by Low-dose Aspirin in Healthy Subjects

Acetylation of platelet cyclooxygenase by oral aspirin is dose dependent and cumulative with repeated administration. However, no single dose of aspirin has been found to be completely selective of platelet thromboxane (TX) synthesis inhibition in man. We determined the dose dependence, cumulative nature and selectivity of aspirin effects on platelet TXB₂ and renal prostaglandin (PG) and prostacyclin (PGI₂) production. We measured, by radioimmunoassay, serum TXB₂ levels after whole blood clotting and urinary excretion of PGE₂, PGF_2α, and 6-keto-PGF_1α, before and after single or repeated oral aspirin doses given to 46 healthy subjects. Single doses of 6-100 mg aspirin resulted in a linear (r = 0.92, P < 0.01) inhibition of platelet TXB₂ production, ranging from 12 to 95% after 24 h. A daily dose of 0.45 mg/kg given for 7 d produced a cumulative and virtually complete inhibition of platelet TXB₂ production, without significantly reducing the urinary excretion of PGE₂, PGF_2α, and 6-keto-PGF_1α in both healthy men and women. The platelet inhibitory effect of this regimen was maintained unaltered throughout 1 mo of therapy, with no evidence of cumulative inhibition of renal PG-synthesis. Moreover, furosemide-induced renal PGI₂ synthesis and renin release were unaffected by chronic low-dose aspirin. Following cessation of aspirin therapy, platelet TXB₂ production returned toward control values at a similar rate as after a single higher dose.     

Overexpressed cyclin D3 contributes to retaining the growth inhibitor p27 in the cytoplasm of thyroid tumor cells

The majority of thyroid carcinomas maintain the expression of the cell growth suppressor p27, an inhibitor of cyclin-dependent kinase-2 (Cdk2). However, we find that 80% of p27-expressing tumors show an uncommon cytoplasmic localization of p27 protein, associated with high Cdk2 activity. To reproduce such a situation, a mutant p27 devoid of its COOH-terminal nuclear-localization signal was generated (p27-NLS). p27-NLS accumulates in the cytoplasm and fails to induce growth arrest in 2 different cell lines, indicating that cytoplasm-residing p27 is inactive as a growth inhibitor, presumably because it does not interact with nuclear Cdk2. Overexpression of cyclin D3 may account in part for p27 cytoplasmic localization. In thyroid tumors and cell lines, cyclin D3 expression was associated with cytoplasmic localization of p27. Moreover, expression of cyclin D3 in thyroid carcinoma cells induced cytoplasmic retention of cotransfected p27 and rescued p27-imposed growth arrest. Endogenous p27 also localized prevalently to the cytoplasm in normal thyrocytes engineered to stably overexpress cyclin D3 (PC-D3 cells). In these cells, cyclin D3 induced the formation of cytoplasmic p27-cyclin D3-Cdk complexes, which titrated p27 away from intranuclear complexes that contain cyclins A-E and Cdk2. Our results demonstrate a novel mechanism that may contribute to overcoming the p27 inhibitory threshold in transformed thyroid cells.