Eosinophil cationic protein and histamine production by neutrophils from patients with periodontitis

1 Background

Periodontitis develops through an inflammatory process caused by an infection at the microbial biofilm, followed by tissue destruction mediated by leukocytes, which cause clinically significant destruction of connective tissue and bone. Several elements derived from the bacteria cause the inflammatory response and the release of mediators involved in destruction of the periodontium. There are number of inflammatory mediators released by leukocytes, mainly neutrophils, upon bacterial challenge. Neutrophils produce and release eosinophil cationic protein (ECP) and histamine, two important inflammatory mediators; however, their role has not been characterized in periodontal inflammation. Thus, the purpose of this study is to investigate whether neutrophils from patients with periodontitis can produce ECP and histamine in response to lipopolysaccharides (LPSs).

2 Methods

ECP and histamine production in response to LPSs was analyzed by enzyme‐linked immunosorbent assay. Expression of the histidine decarboxylase and ECP was also analyzed by flow cytometry and fluorescence microscopy in neutrophils from patients with periodontitis in response to LPS.

3 Results

It was found that neutrophils from patients with periodontitis express higher levels of histidine decarboxylase and ECP than those from healthy volunteers, and they also release higher levels of histamine.

4 Conclusion

Findings described could represent new knowledge indicating neutrophils as a source of histamine and ECP in the progression of periodontitis.     

Physicochemical properties and transport behaviour of piribedil: Considerations on its membrane-crossing potential

The lipophilicity (expressed by log P_oct) and H-bond donor acidity (expressed by Δ log P_oct-hep) of the dopaminergic agonist piribedil in different ionization states were investigated in order to assess its capacity for crossing membranes. The present study showed that piribedil has a relatively high lipophilicity (log P_oct = 2.84) and is a non- or very weak H-bond donor (Δ log P_oct-hep = 0.75), implying optimal properties for transmembranal transport. Based on its microscopic ionization behaviour as studied by ¹³C-NMR spectroscopy and (log P − log P⁺) value (5.04) (a measure of the stability of the ionic vs neutral species in a lipidic phase), protonation proved to be very unfavourable in water-saturated octanol due to the hindrance of solvation by the two bulky groups adjacent to the piperazinyl amino group. In addition, transport of piribedil across a lipophilic membrane was studied according to first-order kinetics in a three-compartment model. The effects of lipophilic counterions on the partitioning behaviour and transfer kinetics were examined and shown to be non-existent at equimolar concentrations.     

Long-term effects of heavy metals in food on developmental stages of Aiolopus thalassinus (Saltatoria: Acrididae)

Newly hatched F₁ nymphs of Aiolopus thalassinus (Fabr.) were fed on food treated with various concentrations of HgCl₂, CdCl₂, and PbCl₂ until the end of adult life. Toxicological observations were followed in the F₁ generation and in the F₂ generation derived from the heavy metal-loaded F₁ parents.The highest concentration of the heavy metals caused 100% mortality of the F₁ adults within four weeks. The nymphal duration of the F₁ and F₂ generations was significantly prolonged after Hg and Cd exposure, but the F₁ of the group treated with lead was not affected. The fresh body weight of adults was significantly reduced in the F₁ generation of most treatments and in the resulting untreated F₂. The lifespan of the F₁ adults was shortened. In the F₂ generation, although the lifespan was somewhat longer, generally it was still shorter than that of the control adults. The mean egg number laid by F₁ adults fed on food contaminated with Hg or Cd was decreased. This decrease was more pronounced in the case of Cd than Hg. In the females fed on food treated with Pb the reduction of the number of egg pods was not remarkable. The hatchability of the eggs laid by F₁ females was significantly reduced as compared to the control. The viability of the eggs laid by F₂ adults was somewhat decreased due to either a reduced number of egg pods or to a lower rate of hatchability, especially in the case of Cd. The treated adults frequently displayed weakness in their legs, difficulties in walking, tremors, and nervous movements. In 1% of the F₁ adults, the wings were abnormally developed being outstretched and bent downward. The last instar nymphs hatching from eggs laid from F₁ adults in PbCl₂-treated soil failed to moult to adults.