Tsuyoshi Saito

Expression of inflammatory cytokine genes in vivo by human alveolar bone-derived polymorphonuclear leukocytes isolated from chronically inflamed sites of bone resorption.

Alveolar bone-derived polymorphonuclear leukocytes (PMNs) were characterized for their ability to produce inflammatory cytokines such as interleukin-1α (IL-1α), IL-1β, tumor necrosis factor α(TNFα), and IL-6in vivo. Periapical exudates (PE) were collected from periapical lesions with chronic periapical periodontitis through root canals. Cells and noncellular supernatants were then isolated by centrifugation. The concentration of cytokines present in the noncellular supernatants were determined by ELISA. High concentrations of IL-1α, IL-1β, and IL-6 were detected in PE, however, TNFα was not. PE contains predominantly PMNs (>95% of residing cells) with a few percent of lymphocytes and/or macrophages. These alveolar bone-derived PMNs were purified by the Ficoll-Hypaque gradient method and were analyzed for cytokine mRNA expression using the cytokine-specific reverse-transcription polymerase chain reaction. Highly purified PMNs (>99.5%) isolated from PE expressed significant levels of mRNA for IL-α, IL-1β, and TNFα. IL-6 mRNA was not detected, although a high concentration of IL-6 was detected in supernatants of PE by ELISA. The IL-6 secretion in PE could be derived from macrophages, T lymphocytes, osteoblasts, or fibroblasts around periapical lesions. These data strongly suggest that human PMNs derived from alveolar bone can spontaneously produce IL-1α, IL-1β, and TNFα at sites of inflammation, and probably initiate inflammation and regulate augmentation of bone resorptionin vivo.

Production of Human-Inducible Nitric Oxide Synthase in Radicular Cysts

To examine if nitric oxide (NO) is produced in radicular cysts, NO synthase (NOS) production was analyzed. Periapical tissues were removed from patients at the time of endodontic surgery. Frozen tissue sections were histologically evaluated with hematoxylin-eosin staining. Production of human-inducible NOS (iNOS) in apical cysts was then immunohistochemically examined. Immunoreactive human iNOS was widely distributed in epithelial cells, endothelial cells, fibroblasts, macrophages, or polymorphonuclear leukocytes. Remarkably, iNOS-positive cells were significantly present around blood vessels, and cells residing apart from the blood vessels showed weak or no iNOS production, suggesting that only cells around blood vessels could be stimulated for iNOS synthesis. These data demonstrated the possibility that several, but not all, cells could be stimulated to synthesize iNOS in inflamed tissues. In the presence of iNOS, NO can be produced spontaneously in periapical lesions and may play a crucial role in the regulation of chronic infection.

A laboratory study of HBsAg detection using punctured blood on gingiva

歯科診療に関連する一連の処置は, 血液や唾液を排除しての診療は不可能であり, 歯科に来院する患者からの感染については十分な注意と予防が必要である。現在行われているHBs抗原検出検査は, 通常R. P. H. A. 法を用いた血清検査であるが, 静脈血の採血は歯科外来での応用には抵抗があるようである。そこで本研究では, 歯科外来で実施できるHBs検出法として耳朶および歯肉穿刺ロ紙血を応用し検出法を検討した結果, 次の結論を得た。1. ロ紙に吸着乾固させた血液を用い, その溶出液についてR. P. H. A. 法に準じた検査方法でHBs抗原の検出を行うことが可能であり, ロ紙血の溶出に5時間が必要であった。2. HBs抗原陽性者2名を含む22名について, 耳朶および歯肉から採取したロ紙血法と従来の血清法とを定性的に比較した結果, 全例で一致した。3. 定量検査をしてロ紙血を応用し且Bs抗原価の測定を行った結果, 血清法と同様に測定が可能であった。