Effects of exogenous tumour necrosis factor-alpha on the secretory function of the bovine reproductive tract depend on tumour necrosis factor-alpha concentrations

The aim of study was to correlate tumour necrosis factor-alpha (TNF) infused doses used with the TNF concentrations achieved and with the secretory function of both the ovary and the uterus in cows. We evaluated the concentrations of progesterone (P4), prostaglandin (PG)F(2alpha), PGE(2) nitric oxide (NO) and TNF in the jugular vein and vena cava caudalis as parameters of exogenous TNF action on the female reproductive tract. Aortae abdominalis of cows (n = 18) were infused with saline or two doses of TNF (luteolytic--1 microg or luteotrophic--10 microg). In the peripheral blood, 1 microg TNF concentrations achieved within the range of 30-45 pg/ml, and 10 microg TNF provoked a sharp increase in achieved concentrations at a range of 250-450 pg/mL). The TNF concentrations achieved in vena cava caudalis were five to six times higher than that in peripheral blood (p < 0.001). One microgram TNF increased PGF(2alpha) and NO (p < 0.001) and decreased P4 (p < 0.05). The higher TNF dose stimulated P4 and PGE(2) (p < 0.01). TNF infusion at luteolytic dose achieved its concentrations at the physiological range previously observed in cows. Luteotrophic TNF dose achieved the concentrations in vena cava caudalis that are much higher than physiological level and were previously noted in pathological circumstances (i.e. mastitis, metritis).

Stimulation of Fusobacterium nucleatum biofilm formation by Porphyromonas gingivalis

BACKGROUND/AIMS

Bacterial infection is a major cause of periapical periodontitis. Eradication of these microorganisms from apical lesions is essential to the success of endodontic treatment. The aim of this study was to clarify the molecular interaction between Fusobacterium nucleatum, Porphyromonas gingivalis and other microorganisms associated with periapical periodontitis.

METHODS

Microorganisms isolated from periapical lesions were inoculated into type-I collagen-coated polystyrene microtiter plates and maintained at 37 degrees C under anaerobic conditions for 2 days, after which, the quantity of organized biofilm on the plates was evaluated by crystal violet staining. Growth enhancement via soluble factor was evaluated by separated coculture using a 0.4-mum membrane filter.

RESULTS

F. nucleatum exhibited strong adherence to type-I collagen-coated polystyrene microplates. Biofilm formation by F. nucleatum was significantly enhanced by P. gingivalis. It was complemented by compartmentalized coculture with P. gingivalis. Enhancement of biofilm formation by P. gingivalis was only slightly reduced by inactivation of its autoinducer-2-producing gene luxS.

CONCLUSION

The results suggest that P. gingivalis enhances biofilm formation by F. nucleatum by releasing diffusible signaling molecules other than autoinducer-2.

Epidermal growth factor receptor gene mutation, amplification and protein expression in malignant pleural mesothelioma

Epidermal growth factor receptor (EGFR) is overexpressed in a variety of epithelial malignancies. In lung cancer cases, EGFR gene mutation at the kinase domain and EGFR gene amplification are reported to be predictors of the response to EGFR tyrosine kinase inhibitors. In malignant pleural mesothelioma (MPM), the role of EGFR is less clear. We studied EGFR gene mutation, amplification and protein expression in 25 Japanese patients with MPM. None had previously reported EGFR mutations detected by the TaqMan PCR assay. Using immunohistochemistry, 8/25 (32%) cases were positive for the EGFR protein. The cases of sarcomatous type and desmoplastic type were all negative. Fluorescence in situ hybridization analysis revealed three low polysomy cases and one high polysomy case. The low polysomy cases included one biphasic type and two epithelial types, and the high polysomy case was epithelial type. These four cases expressed EGFR protein. In MPM, EGFR seems to play a role in a limited subset of patients. To identify possible candidates for EGFR tyrosine kinase in inhibitor therapy, the information on the EGFR gene status may be valuable.

Colonization pattern of periodontal bacteria in Japanese children and their mothers

BACKGROUND AND OBJECTIVE

The purpose of this study was to determine the time of infection by anaerobic gram-negative rods associated with periodontal disease, and to clarify their transmission from mother to child.

MATERIAL AND METHODS

Seventy-eight Japanese children (including 10 siblings), aged from 3 to 9 years, and 68 mothers, were enrolled in this study. Colonization by 11 periodontal bacterial species was determined using polymerase chain reaction amplification of samples of subgingival plaque obtained from the children and their mothers.

RESULTS

The detection rates of Porphyromonas gingivalis, Tannerella forsythensis and Treponema denticola increased in children after the age of 6 years. We found a high consistency in colonization by P. gingivalis, T. denticola, Prevotella intermedia and Prevotella nigrescens in 9 of the 10 siblings. The average number of bacterial species in plaque samples harboring Fusobacterium nucleatum and/or Fusobacterium periodonticum was significantly greater than in those without, in both children and mothers. Kappa statistical analysis revealed that the detection of Capnocytophaga gingivalis, Capnocytophaga ochracea, Campylobacter rectus and T. denticola in children was consistent with that in the mother.

CONCLUSION

Periodontal bacterial colonization in Japanese children increased with age and was associated with F. nucleatum and/or periodonticum, and the bacterial flora in children was similar to that in their mothers.

Inhibitory effect of cranberry polyphenol on biofilm formation and cysteine proteases of Porphyromonas gingivalis

BACKGROUND AND OBJECTIVE

The purpose of this study was to investigate the effects of cranberry polyphenol fraction on biofilm formation and activities of Arg-gingipain and Lys-gingipain in Porphyromonas gingivalis.

MATERIAL AND METHODS

The polyphenol fraction was prepared by using a glass column packed with Amberlite XAD 7HP and 70% aqueous ethanol as an elution solvent.

RESULTS

Synergistic biofilm formation by P. gingivalis and Fusobacterium nucleatum was significantly inhibited by the polyphenol fraction at a concentration of 250 microg/mL compared with untreated controls (p < 0.01). Arg-gingipain and Lys-gingipain activities in P. gingivalis ATCC 33277 and FDC 381 were inhibited significantly at a polyphenol fraction concentration of > or = 1 microg/mL (p < 0.05).

CONCLUSION

These findings indicate that the polyphenol fraction inhibits biofilm formation and the Arg-gingipain and Lys-gingipain activities of P. gingivalis.

Arg-gingipain A DNA vaccine prevents alveolar bone loss in mice

One major pathogenic factor of Porphyromonas gingivalis is Arg-gingipain (Rgp), an arginine-specific cysteine proteinase. To clarify the effect of rgpA DNA vaccine, we immunized BALB/c mice via the abdomen with a Gene Gun or via the nasal cavity weekly for 6 weeks. After immunization, the mice were challenged orally with P. gingivalis. Immunization elicited IgG responses against P. gingivalis in both groups. Nasal immunization also induced sIgA against P. gingivalis, although Gene Gun immunization did not. Reduction of alveolar bone loss was observed in both groups at 42 days following initial infection. This effect was more pronounced in the intranasal immunization group than in the Gene Gun group. The results of this study suggest that immunization with rgpA DNA vaccine via the nasal cavity is an effective method for preventing alveolar bone loss incurred by infection with P. gingivalis.

Professional oral health care by dental hygienists reduced respiratory infections in elderly persons requiring nursing care

OBJECTIVES

Respiratory infection is a major cause of death in the elderly. We have evaluated the role of professional oral health care (POHC) by dental hygienists in reducing respiratory infections in elderly persons requiring nursing care.

METHODS

Two populations of elderly persons, one receiving POHC and one not, were examined to determine numbers of microorganisms, potent pathogens of respiratory infection, enzymatic activity in saliva, fevers, prevalence of fatal aspiration pneumonia and prevalence of influenza.

RESULTS

In the first population, we found a high prevalence of potent respiratory pathogens such as Staphylococcus species, Pseudomonas aeruginosa and Candida albicans. Patients who received POHC showed a lower prevalence for these pathogens than those who did not. The ratio of fatal aspiration pneumonia in POHC patients was significantly lower than that in patients without POHC (non-POHC) over a 24-month period (P < 0.05). The prevalence of a fever of 37.8 degrees C or more in POHC patients was significantly lower than that in the non-POHC group (P < 0.05). In the second study population, we investigated the effects of POHC on infection with influenza over a 6-month period. In the POHC group, neuraminidase and trypsin-like protease activities decreased, and one of 98 patients was diagnosed with influenza; whereas, in the non-POHC group, nine of 92 patients were diagnosed with influenza. The relative risk of developing influenza while under POHC was 0.1 (95% CI 0.01-0.81, P = 0.008).

CONCLUSION

These results suggest that POHC by dental hygienists is effective in preventing respiratory infections in elderly persons requiring nursing care.

The effects of tetracycline, minocycline, doxycycline and ofloxacin on Prevotella intermedia biofilm

Prevotella intermedia, a black-pigmented, anaerobic, gram-negative bacterium, is associated with various type of periodontitis. Antibiotic treatments via a systemic or local route have been reported as being useful for treating periodontal disease. The purpose of this study was to examine the effects of four antibiotics, tetracycline (TET), minocycline (MINO), doxycycline (DOXY) and ofloxacin (OFLX) on P. intermedia biofilms at minimum inhibitory concentrations (MIC) from one-fold to 100-fold. MICs were determined for planktonic cells. Biofilm formation was determined with the crystal violet stain method and the bioactivities in the biofilms were determined with the adenosine triphosphate (ATP) -bioluminescent assay using a 96-well culture plate. At one-fold MIC, DOXY inhibited biofilm formation by P. intermedia ATCC 25611. Other antibiotics at one-fold MIC had no effects on the biofilm formation of tested bacterial strains. In P. intermedia ATCC 25611 biofilms, all the antibiotics tested showed inhibitory activities at five- to 100-fold MICs. In the biofilms of P. intermedia strains, except ATCC 25611, treated with three tetracycline antibiotics, the bioactivities were significantly increased, indicating the difficulties involved in designing antibiotic therapy for periodontal disease.

Enucleated L929 mouse fibroblasts support invasion and multiplication of Shigella flexneri 5a

Invasive bacteria can induce their own uptake and specify their intracellular localization; hence it is commonly assumed that proximate modulation of host cell transcription is not required for infection. However, bacteria can also modulate, directly or indirectly, the transcription of many host cell genes, whose role in the infection may be difficult to determine by global gene expression. Is the host cell nucleus proximately required for intracellular infection and, if so, for which pathogens and at what stages of infection? Enucleated cells were previously infected with Toxoplasma gondii, Chlamydia psittaci, C. trachomatis, or Rickettsia prowazekii. We enucleated L929 mouse fibroblasts by centrifugation in the presence of cytochalasin B, and compared the infection with Shigella flexneri M90T 5a of nucleated and enucleated cells. Percent infection and bacterial loads were estimated with a gentamicin suppression assay in cultures fixed and stained at different times after infection. Enucleation reduced by about half the percent of infected cells, a finding that may reflect the reduced endocytic ability of L929 cytoplasts. However, average numbers of bacteria and frequency distributions of bacterial numbers per cell at different times were similar in enucleated and nucleated cells. Bacteria with actin-rich tails were detected in both cytoplasts and nucleated cells. Lastly, cytoplasts were similarly infected 2 and 24 h after enucleation, suggesting that short-lived mRNAs were not involved in the infection. Productive S. flexneri infection could thus take place in cells unable to modulate gene transcription, RNA processing, or nucleus-dependent signaling cascades.

Prime-boost vaccination with plasmid DNA and a chimeric adenovirus type 5 vector with type 35 fiber induces protective immunity against HIV

Immunization involving a DNA vaccine prime followed by an adenovirus type 5 (Ad5) boost elicited a protective immune response against SHIV challenge in monkeys. However, the hepatocellular tropism of Ad5 limits the safety of this viral vector. This study examines the safety and immunogenicity of a replication-defective chimeric Ad5 vector with the Ad35 fiber (Ad5/35) in BALB/c mice and rhesus monkeys. This novel Ad5/35 vector showed minimal hepatotoxicity after intramuscular administration with the novel Ad5/35 vector. In addition, an Ad5/35 vector expressing HIV Env gp160 protein (Ad5/35-HIV) generated strong HIV-specific immune responses in both animal models. Priming with a DNA vaccine followed by Ad5/35-HIV boosting yielded protection against a gp160-expressing vaccinia virus challenge in BALB/c mice. The Ad5/35-HIV vector was significantly less susceptible to the pre-existing Ad5 immunity than a comparable Ad5 vector. These findings indicate that an Ad5/35 vector-based HIV vaccine may be of considerable value for clinical use.

253 GENE SILENCING OF CYCLOOXYGENASE-2 mRNA BY RNA INTERFERENCE IN BOVINE CUMULUS - GRANULOSA CELLS

Recently, interference RNA (RNAi), inducing inhibition of the specific gene expression, attracted a lot of attention. Many researchers have reported that the 21-mer small interference RNA (siRNA) is introduced into target cells and then siRNA can suppress the gene expression. RNAi is a useful tool for functional analysis of specific genes. However, there is little information about RNAi for the analysis of gene function in reproductive physiology in ruminants. Thus, this study was aimed at evaluating RNAi for the analysis of cyclooxygenase-2 (Cox-2) mRNA expression in bovine cumulus-granulosa (CG) cells as well as prostaglandin F2� (PGF2�) production. We investigated both the effective concentration of Cox-2 siRNA and the effect of the introduction time of siRNA on Cox-2 mRNA expression. Bovine CG cells were collected at slaughterhouse and cultured in 4-well dishes. After the cells reached confluency, two experiments were conducted. In the present study, Cox-2 siRNA was simply added to culture medium with lipofectamine" 2000 (Invitrogen Japan K. K., Tokyo, Japan) as the transfection reagent. In experiment 1, the concentration of 0, 100, 250, and 500 pM of Cox-2 siRNA was introduced into the CG cells. After 24 h of introduction, the amount of mRNA expression for Cox-2 was measured by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. In experiment 2, 250 pM siRNA for Cox-2 was introduced into CG cells for 0, 3, 6, 12, and 24 h. After culture, the amount of mRNA expression for Cox-2 was measured and the culture medium was collected to determine PGF2� concentration by enzyme immunoassay. The Cox-2 mRNA expression was not affected by 100 pM siRNA introduced into CG cells for 24 h, but 250 and 500 pM Cox-2 siRNA significantly reduced the Cox-2 mRNA expression (10% of that of the 0 pM siRNA group). Moreover, the suppressive effect of 250 pM siRNA was observed at 6 h after introduction (60% of that of the 0 pM siRNA group at 0 h) and the reduction of mRNA expression by RNAi became more obvious over 12 h (10% of that of the 0 pM siRNA group at 0 h). On the other hand, the PGF2� concentration in the culture medium was not significantly different at 12 h after siRNA introduction, however, the PGF2� concentration of the RNAi treatment group at 24 h was significantly lower than that of the 0 pM siRNA group at the same time point. These results suggest that gene silencing by Cox-2 siRNA is a means of analyzing the function and expression of specific genes in bovine CG cells. This study was supported by the Japan Society for the Promotion of Science for Young Scientists.

Poly(A)+ RNA and cytoskeleton during cyst formation in the cap ray of Acetabularia peniculus

The configuration and distribution of polyadenylated RNA (poly(A)+ RNA) during cyst formation in the cap rays of Acetabularia peniculus were demonstrated by fluorescence in situ hybridization using oligo(dT) as a probe, and the spatial and functional relationships between poly(A)+ RNA and microtubules or actin filaments were examined by immunofluorescence microscopy and cytoskeletal inhibitor treatment. Poly(A)+ RNA striations were present in the cytoplasm of early cap rays and associated with longitudinal actin bundles. Cytochalasin D destroyed the actin filaments and caused a dispersal of the striations. Poly(A)+ RNA striations occurred in the cytoplasm of the cap rays up to the stage when secondary nuclei migrated into the cap rays, but they disappeared after the secondary nuclei were settled in their positions. At that time, a mass of poly(A)+ RNA was present around each of the secondary nuclei and accumulated rRNA. This mass colocalized with microtubules radiating from the surface of each secondary nucleus and disappeared when the microtubules were depolymerized by butamifos, which did not affect the configuration of actin filaments. These masses of poly(A)+ RNA continued to exist even after the cap ray cytoplasm divided into cyst domains. Thus two distinct forms of poly(A)+ RNA population, striations and masses, appear in turn at consecutive stages of cyst formation and are associated with distinct cytoskeletal elements, actin filaments and microtubules, respectively.

Phytoestrogen metabolites are much more active than phytoestrogens themselves in increasing prostaglandin F(2alpha) synthesis via prostaglanin F(2alpha) synthase-like 2 stimulation in bovine endometrium

Phytoestrogens have recently been suggested to be the cause of infertility by stimulating luteolytic prostaglandin (PG) F(2alpha) secretion from endometrium in cattle. The purpose of this study was to examine the enzymatic and molecular mechanisms involved in the preferential induction of PGF(2alpha) synthesis by phytoestrogens, and whether phytoestrogens influence endometrial cell viability. Cultured bovine endometrial epithelial and stromal cells were exposed to phytoestrogens (daidzein and genistein) and their metabolites (equol and p-ethyl phenol) for 24h. Prostaglandin F(2alpha) and PGE2 were stimulated by phytoestrogens in both stromal and epithelial cells, with a preference for PGF(2alpha) synthesis in epithelial cells (P<0.001). Although RT-PCR and Western Blot analyses did not reveal the influence of phytoestrogens on either gene expression or protein level of cyclooxygenase-2 (COX-2) and PGE2 synthase (PGES) in stromal and epithelial cells (P>0.05), the stimulative effects of equol and p-ethyl phenol on PGF(2alpha) synthase-like 2 (PGFSL2) gene expression and protein level were observed only in epithelial cells (P<0.05). The same compounds did not affect PGFSL2 gene expression and protein in stromal cells (P>0.05). Exposure to phytoestrogens and their metabolites decreased cell viability in both stromal and epithelial cells. Stromal cell viability decreased to 50% of the control and was more evident than that in epithelial cells (P<0.001). The overall results suggest that infertility in cattle, caused by phytoestrogen-dependent preferential stimulation of luteolytic PGF(2alpha) synthesis, is caused by increasing PGFSL2 in epithelial cells, and by decreasing stromal cell viability, which are the main source of luteotropic PGE2 production.

Regulation of prostaglandin synthesis by interleukin-1alpha in bovine endometrium during the estrous cycle

Interleukin (IL)-1 has been suggested to participate in regulation of many reproductive functions. To investigate the possible role of IL-1alpha as a local regulator in bovine endometrium, we determined the effects of IL-1alpha on prostaglandin (PG) E2 and PGF(2alpha) output by the bovine endometrium at different stages of the estrous cycle. The expressions of IL-1alpha and IL-1 receptor type 1 (IL-1RT1) mRNA in bovine endometrium were also studied. Bovine uteri were classified into six stages (estrus: day 0; early luteal: days 2-3; developing luteal: days 5-6; mid luteal: days 8-12; late luteal: days 15-17; and follicular: days 19-21). After 1h of pre-incubation, endometrial tissues (20-30mg) were exposed to 0 or 10ng/ml IL-1alpha for 4h. IL-1alpha significantly stimulated PGE2 output throughout the luteal stages, with the highest response during the mid luteal stage, while it did not stimulate PGE2 output during the estrus and the follicular stage. On the other hand, IL-1alpha significantly enhanced PGF(2alpha) output throughout the estrous cycle except in the endometrium from the mid luteal stage, with the highest response at the follicular stage (P<0.001). The treatment of endometrial tissue with IL-1alpha resulted in an increase of the PGE2:PGF(2alpha) ratio at the mid luteal stage, and in a decrease during the late luteal and follicular stages of the estrous cycle. A semiquantitative reverse transcription-polymerase chain reaction revealed that IL-1alpha and IL-1RT1 mRNA are expressed in the endometrium throughout the estrous cycle. IL-1alpha mRNA expression was greater in the early luteal stage than in the estrus, late luteal, and follicular stages (P<0.05). IL-1RT1 mRNA was greater in the late luteal stage than in the other stages (P<0.05). The overall results suggest that IL-1alpha is produced in bovine endometrium throughout the estrous cycle, and plays some roles not only in maintenance of CL, but also in luteolysis by regulating the local PGE2:PGF(2alpha) ratio in bovine endometrium during the estrous cycle.

Immunization by Arg-gingipain A DNA vaccine protects mice against an invasive Porphyromonas gingivalis infection through regulation of interferon-gamma production

We previously demonstrated that a Porphyromonas gingivalis rgpA DNA vaccine induced protective immune responses against P. gingivalis infection in mice. In the present study, reduction in lethality against infection by lethal doses of P. gingivalis was observed in the rgpA DNA vaccine-immunized mice. Cytokine levels in the mouse model with nonlethal doses of infection by P. gingivalis were evaluated to analyze the mechanism of protection by immunization with the rgpA DNA vaccine. After nonlethal challenge with invasive P. gingivalis W50, production of interleukin (IL)-2, IL-4, IL-5 and IL-12 was elevated; however, interferon (IFN)-gamma was lower in the serum of the DNA vaccine-immunized mice than in the serum of nonimmunized mice. The regulation of IFN-gamma production elicited by immunization with the rgpA DNA vaccine may play a significant role in protection against P. gingivalis infection in mice.

Detection of heat shock proteins but not superantigen by isolated oral bacteria from patients with Behcet's disease

We isolated bacteria from periodontal sites and mixed saliva in eight patients with Behcet's disease and surveyed them to determine whether they produced heat shock proteins (HSPs) and superantigen. Cultivable bacterial compositions from periodontal sites and saliva were examined by anaerobic culture using blood agar plates. Gram-negative anaerobic rods such as Prevotella intermedia, Fusobacterium nucleatum, and Capnocytophaga species were predominant in the isolates from the subgingival plaque samples. The Streptococcus mitis group was the most common type isolated from the saliva samples. To detect the production of HSPs, Western blot analyses were performed using a polyclonal rabbit antibody to Escherichia coli DnaK and a monoclonal antibody to Helicobacter pylori Gro-EL. Sonic extracts of 27 of the strains (79.4%) reacted with the antibody against E. coli DnaK. Nine of these 34 strains (26.5%) were found to produce HSPs that reacted with antibody to H. pylori Gro-EL. A total of 54 isolates were examined for superantigen activity against human peripheral leukocytes. Twenty-five gram-negative clinical strains isolated from chronic periodontitis lesions and 20 ATCC strains of microorganisms were also examined. We could not detect any superantigen activity in 500x diluted supernatant of the strains isolated from the eight patients with Behcet's disease. The present study indicates that the anaerobic strains isolated from the oral cavity of these patients produce HSPs, the production being related to Bechet's disease.

Salivary bisphenol-A levels detected by ELISA after restoration with composite resin

Bisphenol-A diglycidylether methacrylate (Bis-GMA), which is synthesized from bisphenol-A (BPA), a compound with exogenous endocrine disrupter action, is widely used as a dental material. During clinical filling with sealants and composite resins, the compounds are solidified by polymerization and then used. However, it has been noted that unpolymerized monomers may become dissolved in saliva. In this study using a competitive ELISA system, we investigated the changes in the BPA concentration in saliva after restoration with composite resins. Commercial composite resins from nine companies were tested. Mixed saliva was collected from 21 subjects. Based on the dynamics of salivary BPA detected by this ELISA system, we concluded that several tens to 100 ng/ml of BPA were contained in saliva after filling teeth with composite resin but that sufficient gargling can remove it from the oral cavity. Our data suggest that sufficient gargling after treatment is important for risk management.

Signal transduction and cellular functions of the TEL/ARG oncoprotein

The TEL/ARG oncogene is formed by t(1;12)(q25;p13) reciprocal translocation and is associated with human leukemia. We have previously demonstrated that the expression of TEL/ARG in Ba/F3 cells results in prolonged viability and hyper-responsiveness to IL-3. To determine the molecular mechanisms, a series of mutants of TEL/ARG were generated, and each cDNA was expressed in Ba/F3 or CHO cells. The PNT domain in TEL and K317 in ARG were essential for both signaling and biological effects. The SH3 domain in ARG was required for hyper-responsiveness to IL-3, but not for prolonged viability. The opposite was true for the SH2 domain in ARG. Mutation of Y314 in TEL, a putative GRB2-binding site, led to reduced viability, and loss of hyper-responsiveness to IL-3. All biological functions were profoundly impaired with deletion of the C-terminus in ARG, despite maintaining high levels of its kinase activity. When expressed in CHO cells, wild-type TEL/ARG induced the formation of fillopodia, in a fashion dependent on the C-terminal portion and intact kinase activity. Thus, these results suggest several critical domains within TEL/ARG necessary for function, and indicate that the signaling pathways necessary for viability, growth factor hyper-responsiveness and cytoskeletal reorganization are likely to be separate.

Histatin 5 inhibits apoptosis in human gingival fibroblasts induced by porphyromonas gingivalis cell-surface polysaccharide

The cell-surface components of Porphyromonas gingivalis have various biological activities. In the present study, we investigated the virulence of several cell-surface components prepared from P. gingivalis in human gingival fibroblasts (HGF). Furthermore the preventive effect of salivary protein histatin 5 was investigated. P. gingivalis polysaccharide (PS) significantly inhibited HGF proliferation, but lipopolysaccharide and outer-membrane protein did not. By using ELISA analysis, DNA fragmentation in HGFs was observed intracellularly when treated with the PS. These results suggest that the PS of P. gingivalis can induce apoptosis in HGF. Pretreatment of PS with histatin 5 restrained the inhibitory effect of PS on HGF proliferation. Histatin 5 also suppressed the apoptotic cell death in HGF induced by PS stimulation. The present study suggests that the PS of P. gingivalis can modulate the cell population in periodontal tissue, causing periodontitis by inducing HGF cell death through apoptosis. Also histatin 5 can inhibit the PS activity and may play an important part in the regulation of inflammatory periodontal diseases.

Inhibitory effects of cranberry juice on attachment of oral streptococci and biofilm formation

Cranberry juice is known to inhibit bacterial adhesion. We examined the inhibitory effect of cranberry juice on the adhesion of oral streptococci strains labeled with [3H]-thymidine to saliva-coated hydroxyapatite beads (s-HA). When the bacterial cells were momentarily exposed to cranberry juice, their adherence to s-HA decreased significantly compared with the control (P < 0.01). Their hydrophobicity also decreased dependently with the concentration of cranberry juice. We also evaluated the inhibitory effect of cranberry juice on biofilm formation. By using a microplate system, we found that the high molecular mass constituents of cranberry juice inhibited the biofilm formation of the tested streptococci. The inhibitory activity was related to the reduction of the hydrophobicity. The present findings suggest that cranberry juice component(s) can inhibit colonization by oral streptococci to the tooth surface and can thus slow development of dental plaque.

A comparison of the antibacterial efficacies of essential oils against oral pathogens

Cariogenic bacteria and periodontopathic bacteria are present in dental plaque as biofilms. In this study, we investigated the antibacterial effects of essential oils on the following oral bacteria: Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Streptococcus mutans, and Streptococcus sobrinus. We tested manuka oil, tea tree oil, eucalyptus oil, lavandula oil, and romarinus oil and determined their minimum inhibitory concentration and minimum bactericidal concentration. The essential oils inhibited the growth of the bacteria tested, manuka oil being the most effective. Minimum bactericidal concentration values showed that lavandula oil acts bacteriostatically, and the remaining oils, bactericidally. Periodontopathic bacterial strains tested were killed completely by exposure for 30 s to 0.2% manuka oil, tea tree oil or eucalyptus oil. Tea tree oil and manuka oil showed significant adhesion-inhibiting activity against P. gingivalis. All the essential oils tested inhibited the adhesion of S. mutans. This study showed that, among the essential oils tested, manuka oil and tea tree oil in particular had strong antibacterial activity against periodontopathic and cariogenic bacteria. From the viewpoint of safety, we also examined the effects of these essential oils on cultured human umbilical vein endothelial cells and found that, at a concentration of 0.2%, they had little effect on cultured cells.

Daily nasal inoculation with the insulin gene ameliorates diabetes in mice

The present study examined the feasibility of liposome-mediated gene transfer via nasal administration, for treating insulin-dependent diabetes mellitus. The rat insulin gene was packed under control of the CMV promoter, complexed with DC-chol/DOPE-based liposomes and administered daily via the nasal route in mice made severely diabetic by streptozocin. Sustained expression of the insulin gene was achieved and insulinopenia, ketonuria and death were prevented. Hyperglycemia and body weight reduction were significantly suppressed without evidence of hypoglycemia throughout the experimental period. RT-PCR and FISH analysis indicated that insulin was produced in the alveolar epithelial cells of the lung. Liposome-mediated in vivo gene transfer via nasal administration may provide an efficacious route for delivery of hormonal and other gene products into the blood stream.

Involvement of periodontopathic biofilm in vascular diseases

Oral bacteria inhabit biofilms, which are firm clusters adhering in layers to surfaces and are not easily eliminated by immune responses and are resistant to antimicrobial agents. Dental plaque is one such biofilm. In the past 10 years, subgingival plaque bacteria forming biofilms have been increasingly reported to be involved in systemic diseases. A close relationship between microbial infections and vascular disease has also been reported in the past two decades. The present review discusses the significance of the ecologic characteristics of biofilms formed by periodontopathic bacteria in order to further clarify the associations between periodontal disease and systemic disease. We focus on the relationships between periodontal disease-associated bacteria forming biofilms and vascular diseases including atherosclerosis and carotid coronary stenotic artery disease, and we discuss the direct and indirect effects on vascular diseases of lipopolysaccharides as well as heat shock proteins produced by periodontopathic bacteria.