Luminescence of Rare Earth Doped Porous Silicon

Photoluminescence characteristics of porous silicon layers (PSLs) doped with Er or Yb ions are studied. 10μm thick PSLs with a luminescence centered at ∼ 0.8μm are formed by anodic etching of p-type silicon wafers of several Ω-cm resistivity. Rare-earth ions are electrochemically incorporated into PSLs. The Er3+-related luminescence at 1.54μm as well as the Yb3+-related luminescence at 1.0μm is observed at room temperature after annealing at high temperatures (>900°C). The Er-related luminescence is enhanced after annealing in O2, whereas the Yb3+-related luminescence needs oxygen-free atmosphere (H2) for the optical activation. The luminescence decay time of the rare earth ions as well as the host PSLs is measured and the energy transfer mechanism is discussed.

Proinflammatory effects of muramyldipeptide on human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Because human gingival fibroblasts (HGFs) are the predominant cells in periodontal tissues, we hypothesized that HGFs are contributed to receptors for components of bacteria. In this study, we focused on expression and function of nucleotide binding oligomerization domain 2 (NOD2) in HGFs, which is a mammalian cytosolic pathogen recognition molecule.

MATERIAL AND METHODS

Expression of NOD2 in HGFs was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry. Production of interleukin (IL)-6, IL-8, cc chemokine ligand2, cxc chemokine ligand10 (CXCL10) and CXCL11 from HGFs was examined by enzyme-linked immunosorbent assay (ELISA). We used RT-PCR and immunohistochemistry to detect the NOD2 expression in human gingival tissues.

RESULTS

We found clear NOD2 expression in HGFs. Upon stimulation with NOD2 agonist, muramyldipeptide (MDP), production of proinflammatory cytokines was enhanced. Moreover, MDP-induced production of proinflammatory cytokines was inhibited in a different manner by mitogen-activated protein kinase inhibitors and phosphatidylinositol 3-kinase inhibitor. Furthermore, MDP enhanced CXCL10 and CXCL11 productions by tumor necrosis factor-alpha (TNF-alpha)- or interferon-gamma (IFN-gamma)-stimulated HGFs, although MDP alone did not induce these chemokines. TNF-alpha and IFN-gamma increased NOD2 expression in HGFs. In addition, we detected NOD2 expression in mononuclear cells and HGFs in periodontally diseased tissues.

CONCLUSION

These findings indicate that MDP which induces production of cytokines and chemokines from HGFs is related to the pathogenesis of periodontal disease.

Human gingival fibroblasts express functional chemokine receptor CXCR6

We have reported that CXCL16, a recently discovered transmembrane chemokine, is expressed in human gingival fibroblasts (HGF). However, it is not known whether HGF express CXCR6, the receptor for CXCL16, or CXCL16 affects HGF biology. We have shown that HGF expressed CXCR6 by reverse transcription-polymerase chain reaction and flow cytometric analysis. Moreover, we elucidated that tumour necrosis factor (TNF)-alpha and cytosine-guanine dinucleotide (CpG) DNA (Toll-like receptor-9 ligand) treatment enhanced CXCR6 expression by HGF. Interleukin (IL)-4, IL-13 and CpG DNA up-regulated CXCR6 expression by TNF-alpha-stimulated HGF. On the other hand, IL-1beta and interferon-gamma inhibited CXCR6 expression on TNF-alpha-treated HGF. CXCL16 treatment induced HGF proliferation and phosphorylation of extracellular regulated kinase (ERK) and protein kinase B (AKT) in HGF. In conclusion, HGF expressed CXCR6 functionally, because CXCL16 induced HGF proliferation and ERK and AKT phosphorylation in HGF. These results indicate that CXCL16 may play an important role in the pathogenesis and remodelling in periodontally diseased tissues.

CC chemokine ligand 17 in periodontal diseases: expression in diseased tissues and production by human gingival fibroblasts

BACKGROUND AND OBJECTIVE

It has been reported that T helper 2 (Th2) cells are related to exacerbation of periodontal disease. However, it is uncertain how the migration of Th2 cells is controlled. In this study, we examined the expression of CC chemokine ligand 17 (CCL17), which is a Th2 chemokine, in periodontal tissues. Moreover, we investigated the effects of cytokines and toll-like receptor (TLR) ligands on the production of CCL17 by human gingival fibroblasts (HGFs).

MATERIAL AND METHODS

We used immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) to detect CCL17 in periodontal tissues. HGFs were exposed to cytokines and TLR ligands. Expression of CCL17 was examined by RT-PCR and enzyme-linked immunosorbent assay. We used signal transduction inhibitors in some experiments.

RESULTS

Both CCL17 and its receptor, CC chemokine receptor 4 (CCR4), were expressed in diseased periodontal tissues. A combination of tumour necrosis factor alpha (TNF-alpha) and interleukin (IL)-4/IL-13 increased CCL17 expression. Moreover, treatment of HGFs with a low dose of interferon-gamma (IFN-gamma) in combination with TNF-alpha and IL-4 or IL-13 had synergistic effects on the production of CCL17, whereas a high dose of IFN-gamma inhibited CCL17 production. Furthermore, Escherichia coli (E. coli) lipopolysaccharide (TLR4 ligand) and Pam3CSK4 (TLR2 ligand) inhibited CCL17 production by TNF-alpha + IL-4-stimulated HGFs, while CpG DNA (TLR9 ligand) enhanced TNF-alpha + IL-4 induced-CCL17 production by HGFs. Furthermore, a c-Jun NH2 terminal kinase (JNK) inhibitor, a phosphatidylinositol-3-kinase (PI3K) inhibitor and a nuclear factor kappa B (NF-kappa B) inhibitor inhibited CCL17 production by HGFs.

CONCLUSION

These results suggest that the CCL17 produced by HGFs may be involved in the migration of Th2 cells into inflamed tissues, and provide evidence that CCL17 production is controlled by cytokines and TLR ligands in periodontal disease.

Adrenomedullin suppresses tumour necrosis factor alpha-induced CXC chemokine ligand 10 production by human gingival fibroblasts

Periodontal disease is an inflammatory disorder characterized by the involvement of chemokines that are important for the recruitment of leucocytes. Several cytokines, including tumour necrosis factor alpha (TNF-alpha), are involved in regulating levels of chemokines in periodontal disease. CXC chemokine ligand 10 (CXCL10) is a chemokine related to the migration of T helper 1 cells. In this study, we examined CXCL10 expression in human gingival fibroblasts (HGFs). Moreover, we investigated the effects of adrenomedullin (AM), which is a multi-functional regulatory peptide, on the production of CXCL10 by HGFs. We revealed that TNF-alpha stimulation induced CXCL10 production by HGFs. HGFs expressed AM and AM receptors, calcitonin-receptor-like receptor (CRLR) and receptor-activity-modifying protein (RAMP) 2, mRNAs constitutively. AM treatment supressed CXCL10 production by TNF-alpha-stimulated HGFs. Moreover, we elucidated that AM produced by HGFs inhibited CXCL10 production by HGFs, because AM antagonist enhanced CXCL10 production by HGFs. TNF-alpha treatment enhanced CRLR and RAMP2 mRNA expression in HGFs. Furthermore, AM is expressed in human periodontal tissues, including both inflamed and clinically healthy tissues. These results suggest that the CXCL10 produced by HGFs may be involved in the migration of leucocytes into inflamed tissues and related to exacerbation of periodontal disease. AM might be a therapeutic target of periodontal disease, because AM can inhibit CXCL10 production by HGFs.

CXC chemokine ligand 16 in periodontal diseases: expression in diseased tissues and production by cytokine-stimulated human gingival fibroblasts

Periodontal disease is an inflammatory disorder characterized by the involvement of chemokines that are important for the recruitment of leucocytes. Several cytokines are involved in regulating levels of chemokines in periodontal disease. CXCL16 is a chemokine related to the migration of T helper 1 (Th1) cells and natural killer (NK) cells. In this study, we examined its expression in periodontal tissues. Moreover, we investigated the effects of cytokines on the production of CXCL16 by human gingival fibroblast (HGF). Reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry revealed that CXCL16 and its receptor, CXCR6, were expressed at the mRNA and protein levels in diseased tissues. Proinflammatory cytokines [interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma] increased the mRNA expression and release of CXCL16 in a dose-dependent manner. Moreover, treatment of HGFs with IFN-gamma in combination with IL-1beta had a synergistic effect on the production of CXCL16. On the other hand, IL-4 and IL-13 inhibited the IL-1beta-induced CXCL16 production by HGFs. Inhibitors of A disintegrin and metalloprotease (ADAM)10 and ADAM17, a recently identified protease of CXCL16, reduced the amount of CXCL16 released from HGFs. These results suggest that the CXCL16 produced by HGFs may be involved in the migration of leucocytes into inflamed tissues, and provide evidence that CXCL16 production is controlled by cytokines in periodontal disease.

Proinflammatory effects of tumour necrosis factor-like weak inducer of apoptosis (TWEAK) on human gingival fibroblasts

Tumour necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK), a member of the TNF family, is a multi-functional cytokine that regulates cellular proliferation, angiogenesis, inflammation and apoptosis. In this study, we investigated TWEAK expression in periodontally diseased tissues and the effect of TWEAK on human gingival fibroblasts (HGF). Reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry revealed that TWEAK and the TWEAK receptor, fibroblast growth factor-inducible 14 (Fn14), mRNA and protein were expressed in periodontally diseased tissues. HGF expressed Fn14 and produced interleukin (IL)-8 and vascular endothelial growth factor (VEGF) production upon TWEAK stimulation in a dose-dependent manner. The IL-8 and VEGF production induced by TWEAK was augmented synergistically by simultaneous stimulation with transforming growth factor (TGF)-beta1 or IL-1beta. IL-1beta and TGF-beta1 enhanced Fn14 expression in a dose-dependent manner. Moreover, TWEAK induced intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression on HGF in a dose-dependent manner. The ICAM-1 expression induced by TWEAK was augmented by TGF-beta1. On the other hand, the TWEAK-induced VCAM-1 expression was inhibited by TGF-beta1. Phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappaB (NF-kappaB) inhibitor inhibit both ICAM-1 and VCAM-1 expression induced by TWEAK. However, mitogen-activated protein kinase (MEK) and c-Jun NH2-terminal kinase (JNK) inhibitor enhanced only VCAM-1 expression on HGF. These results suggest that TWEAK may be involved in the pathophysiology of periodontal disease. Moreover, in combination with IL-1beta or TGF-beta1, TWEAK may be related to the exacerbation of periodontal disease to induce proinflammatory cytokines and adherent molecules by HGF.

Innate immune peptide LL-37 displays distinct expression pattern from beta-defensins in inflamed gingival tissue

Anti-microbial peptides produced from mucosal epithelium appear to play pivotal roles in the host innate immune defence system in the oral cavity. In particular, human beta-defensins (hBDs) and the cathelicidin-type anti-microbial peptide, LL-37, were reported to kill periodontal disease-associated bacteria. In contrast to well-studied hBDs, little is known about the expression profiles of LL-37 in gingival tissue. In this study, the anti-microbial peptides expressed in gingival tissue were analysed using immunohistochemistry and enxyme-linked immunosorbent assay (ELISA). Immunohistochemistry revealed that neutrophils expressed only LL-37, but not hBD-2 or hBD-3, and that such expression was prominent in the inflammatory lesions when compared to healthy gingivae which showed very few or no LL-37 expressing neutrophils. Gingival epithelial cells (GEC), however, expressed all three examined anti-microbial peptides, irrespective of the presence or absence of inflammation. Moreover, as determined by ELISA, the concentration of LL-37 in the gingival tissue homogenates determined was correlated positively with the depth of the gingival crevice. Stimulation with periodontal bacteria in vitro induced both hBD-2 and LL-37 expressions by GEC, whereas peripheral blood neutrophils produced only LL-37 production, but not hBD-2, in response to the bacterial stimulation. These findings suggest that LL-37 displays distinct expression patterns from those of hBDs in gingival tissue.

Cytokines differentially regulate ICAM-1 and VCAM-1 expression on human gingival fibroblasts

The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) on human gingival fibroblasts (HGF) may be important for migration and retention of inflammatory cells in periodontally diseased tissue. This study aimed to assess which cytokines regulate ICAM-1 and VCAM-1 expression on HGF. Tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma enhanced both ICAM-1 and VCAM-1 expression on HGF. Interleukin (IL)-1beta mainly up-regulated ICAM-1 expression. On the other hand, IL-4 and IL-13 enhanced only VCAM-1 expression on HGF. IL-10 did not modulate both ICAM-1 and VCAM-1 expression. Transforming growth factor (TGF)-beta1 enhanced ICAM-1 expression. However, TGF-beta1 inhibited the VCAM-1 expression induced by TNF-alpha or IL-4. Both ICAM-1 and VCAM-1 expression by HGF was inhibited by nuclear factor-kappaB (NF-kappaB) activation inhibitor (MG-132). Mitogen-activated protein kinases (MAPK) inhibitors did not influence ICAM-1 expression induced by TNF-alpha. Interestingly, VCAM-1 expression was enhanced by MEK inhibitor (PD98059) and c-Jun NH2-terminal kinase (JNK) inhibitor (SP600125). These results mean that the balance of cytokines in periodontally diseased tissue may be essential for control of ICAM-1 and VCAM-1 expression on HGF, and the balance of ICAM-1 and VCAM-1 expression might be important for regulation of leucocytes infiltration and retention in periodontally diseased tissue.

Increase of CCL20 expression by human gingival fibroblasts upon stimulation with cytokines and bacterial endotoxin

We have demonstrated recently that CCL20 was expressed in periodontal diseased tissues and abundant CCR6 positive T cells infiltrated in periodontally diseased tissue. However, it is uncertain which cells can elicit CCL20 production. In the present study, we examined the properties of CCL20 production by human gingival fibroblasts (HGF) culture. Here, we report that interleukin-1 beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and Escherichia coli lipopolysaccharide (LPS) can significantly induce the production of CCL20 by HGF. We found that TNF-alpha and E. coli LPS enhanced the production of CCL20 by HGF treated with IL-1beta. In contrast, interferon-gamma (IFN-gamma) dramatically diminished CCL20 production induced by IL-1beta. Moreover, we demonstrated that nuclear factor-kappaB (NF-kappaB), p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK) play an important role in mediating the production of CCL20 induced by IL-1beta and TNF-alpha. On the other hand, we found that not only NF-kappaB, p38 MAPK and ERK but also c-Jun NH2-terminal kinase (JNK) are involved in CCL20 production induced by E. coli LPS. Finally, we found that HGF express CCR6, CCL20 receptor, and CCL20 induced vascular endothelial growth factor (VEGF) by HGF. Taken together, these findings that HGF will be a source of CCL20 in periodontal tissue, and the CCL20 production will be controlled by proinflammatory cytokine and bacterial LPS in periodontally diseased tissue. Thus, CCL20 by HGF might be involved in inflammatory cells infiltration, and promote the progression of periodontal disease.

CXCL12 and CXCR4 expression by human gingival fibroblasts in periodontal disease

CXCL12 is a CXC chemokine that is related to lymphocyte infiltration and angiogenesis in inflammatory sites such as arthritis. However, the expression and roles of CXCL12 in periodontal disease are uncertain. The aim of this study was to assess the expression of CXCL12 and its receptor, CXCR4, in periodontal tissue and to investigate the properties of CXCL12 and CXCR4 expression by human gingival fibroblasts (HGF). RT-PCR analysis revealed that CXCL12 and CXCR4 mRNA were expressed in both normal gingival tissues and periodontal diseased tissues. Immunohistochemistry disclosed that CXCL12 was expressed and CXCR4 positive cells were found in both normal and periodontal diseased gingival tissues. Our in vitro experiments elucidated that HGF constitutively produced CXCL12, and the levels were enhanced by stimulation with tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), regulated upon activation normal T cell expressed and secreted (RANTES) and macrophage inflammatory protein 3(alpha) (MIP-3(alpha)). On the other hand, heat killed Porphyromonas gingivalis (P. gingivalis) and P. gingivalis LPS reduced the CXCL12 production by HGF. Flow cytometry analysis clarified that CXCR4 was highly expressed on HGF, and CXCR4 expression was abrogated by TNF-alpha, IFN-gamma and P. gingivalis LPS. Moreover, CXCL12 induced vascular endothelial growth factor (VEGF) production by HGF. Our results demonstrated that CXCL12 might be related to CXCR4+ cells infiltration and angiogenesis both in normal periodontal tissues and periodontal diseased tissue. P. gingivalis, a known periodontal pathogen, inhibits the production of CXCL12 and the expression of CXCR4 by HGF. This fact means that P. gingivalis may inhibit CXCR4+ cells infiltration and neovascularization in periodontal tissue and escape from the immune response.

Contamination of room door handles by methicillin-sensitive/methicillin-resistant Staphylococcus aureus

We investigated the contamination of room door handles by Staphylococcus aureus in wards of a university hospital. Door handles in 53 (27.0%) of 196 rooms were contaminated by methicillin-sensitive Staphylococcus aureus (MSSA) and/or methicillin-resistant Staphylococcus aureus (MRSA); MSSA was detected on door handles of 41 rooms (20.9%), MRSA on door handles of 17 rooms (8.7%), and MSSA and MRSA on the same door handles of five rooms (2.6%). The density of MSSA contamination was 1-2.6x10(4) colony forming units (cfu)/door handle, and that of MRSA was 1-6.0x10(3) cfu/door handle. The MRSA contamination rate on door handles of rooms with patients with MRSA was 19.0% (4/21 rooms) while that on door handles of rooms with patients without MRSA was 7.4% (13/175); the difference was not significant. These results suggest extensive contamination of MSSA and MRSA in the hospital environment.

[An autopsy case of a gastric cancer associated with elevated AFP, CEA and CA19-9]

A 48-year-old male developed gastric cancer (Borrmann III) with lung and liver metastases. Laboratory examination revealed a markedly elevated AFP (24, 241 ng/ml), CEA (9739.8 ng/ml), and CA-19-9 (726U/ml). Nevertheless, he underwent a subtotal gastrectomy for the hemostasis of a bleeding malignant lesion. Histological examination showed a moderately differentiated adenocarcinoma. A PAP for an AFP and a CEA disclosed positive staining. In addition, An autopsy revealed metastases to the liver and lungs with a positive result of PAP for AFP and CEA. Further, CA19-9 also was confirmed weakly in these same tissues, histochemically. Therefore this gastric cancer was considered an AFP, CEA, and CA19-9-producing tumor. Gastric cancer with 3 elevated tumor markers in the same patient is rare and its mechanism may elucidate the origin of gastric cancer and the resulting differentiation in the foregut.