Relationship between halitosis and periodontal disease - associated oral bacteria in tongue coatings

AIM

The objective of our study was to investigate the relationship between halitosis and oral bacteria in tongue coating (TC) and saliva samples from patients with halitosis, and to evaluate the effect of tongue cleaning on halitosis.

METHODS

Ninety-four participants complaining of oral malodour were included in the study. Organoleptic (OR) values, volatile sulphur compound (VSC) concentrations determined by gas chromatography and TC scores were used as clinical parameters of halitosis. Quantitative real-time polymerase chain reactions were used to determine the numbers of periodontal disease-associated oral bacteria.

RESULTS

There was a significant correlation between TC scores and OR values, methylmercaptan (CH3 SH) concentrations and VSC concentrations (Spearman's rank-correlation coefficient test, P < 0.01). There was also a positive correlation between the clinical parameters of halitosis and total bacterial numbers and Prevotella intermedia, Fusobacterium nucleatum and Campylobacter rectus concentrations in the TC samples. However, there was no similar correlation with respect to the saliva samples. The participants were sub-divided into two groups based on whether they had the habit of tongue cleaning or not. The participants with the habit of tongue cleaning had significantly lower OR scores, VSC concentrations and P. intermedia, F. nucleatum and C. rectus levels than the other participants (Mann-Whitney U-test, P < 0.05).

CONCLUSION

These results suggested that periodontal disease-associated oral bacteria in TCs are closely related to halitosis and that tongue cleaning may be an effective method for improving halitosis.

Diet and density dependent competition affect larval performance and oviposition site selection in the mosquito species Aedes albopictus (Diptera: Culicidae)

Background

Oviposition-site choice is an essential component of the life history of all mosquito species. According to the oviposition-preference offspring-performance (P-P) hypothesis, if optimizing offspring performance and fitness ensures high overall reproductive fitness for a given species, the female should accurately assess details of the heterogeneous environment and lay her eggs preferentially in sites with conditions more suitable to offspring.

Methods

We empirically tested the P-P hypothesis using the mosquito species Aedes albopictus by artificially manipulating two habitat conditions: diet (measured as mg of food added to a container) and conspecific density (CD; number of pre-existing larvae of the same species). Immature development (larval mortality, development time to pupation and time to emergence) and fitness (measured as wing length) were monitored from first instar through adult emergence using a factorial experimental design over two ascending gradients of diet (2.0, 3.6, 7.2 and 20 mg food/300 ml water) and CD (0, 20, 40 and 80 larvae/300 ml water). Treatments that exerted the most contrasting values of larval performance were recreated in a second experiment consisting of single-female oviposition site selection assay.

Results

Development time decreased as food concentration increased, except from 7.2 mg to 20.0 mg (Two-Way CR ANOVA Post-Hoc test, P > 0.1). Development time decreased also as conspecific density increased from zero to 80 larvae (Two-Way CR ANOVA Post-Hoc test, P < 0.5). Combined, these results support the role of density-dependent competition for resources as a limiting factor for mosquito larval performance. Oviposition assays indicated that female mosquitoes select for larval habitats with conspecifics and that larval density was more important than diet in driving selection for oviposition sites.

Conclusions

This study supports predictions of the P-P hypothesis and provides a mechanistic understanding of the underlying factors driving mosquito oviposition site selection.

The Development and Implementation of a Cognitive-Based Intervention Aimed at Culturally Diverse Women at Risk for HIV/AIDS

The development and implementation of a culturally and gender sensitive, cognitive behavioral-intervention program aimed at preventing high-risk sexual and drug-use behaviors among culturally diverse women at risk for HIV/AIDS is described. The intervention stressed education, cultural/social barriers to change, and assertiveness/negotiation skill building. Methodological problems and their solutions are presented. The article stresses ways to recruit poor at-risk women, how to reduce attrition using incentives such as providing transportation, having food and child care at the intervention sessions, financial rewards, and a tracking system that includes many friends and family members of the participant. Preliminary findings indicated that the intervention was successful in promoting knowledge about HIV/AIDS. At the end of the six-week intervention protocol, the intervention group compared to the control group showed significant improvements in HIV/AIDS knowledge items dealing with clinical aspects of the disease, transmission knowledge, and partner risk knowledge. Knowledge, along with motivation to reduce risk and negotiation skills are essential in changing behaviors that put one at risk.

Amelogenin enhances the osteogenic differentiation of mesenchymal stem cells derived from bone marrow

Amelogenins are the major constituent of developing extracellular enamel matrix proteins and are understood to have an exclusively epithelial origin. Recent studies have demonstrated that amelogenins can be detected in other tissues, including bone marrow mesenchymal stem cells (MSCs), but the role of amelogenins in MSCs remains unclear. The purpose of this study was to examine the effect of recombinant human full-length amelogenin (rh174) on the osteogenic differentiation of cultured human MSCs. MSCs isolated from human bone marrow were cultured in osteoblastic differentiation medium with 0, 10 or 100 ng/ml rh174. The mRNA levels of bone markers were examined by real-time PCR analysis. Alkaline phosphatase (ALP) activity and calcium concentration were determined. Mineralization was evaluated by alizarin red staining. The mRNA levels of ALP, type I collagen, osteopontin and bone sialoprotein in the MSCs treated with rh174 became significantly higher than those in non-treated controls. Treatment of MSCs with rh174 also enhanced ALP activity and calcium concentration, resulting in enhanced mineralization, as denoted by high intensity of alizarin red staining. In conclusion, the present study showed that rh174 enhances the mineralization accompanied by the upregulation of bone markers in human bone marrow MSCs during osteogenic differentiation, suggesting a certain role of amelogenin in the modulation of osteogenic differentiation of MSCs.

Ecological patterns of blood-feeding by kissing-bugs (Hemiptera: Reduviidae: Triatominae)

Host use by vectors is important in understanding the transmission of zoonotic diseases, which can affect humans, wildlife and domestic animals. Here, a synthesis of host exploitation patterns by kissing-bugs, vectors of Chagas disease, is presented. For this synthesis, an extensive literature review restricted to feeding sources analysed by precipitin tests was conducted. Modern tools from community ecology and multivariate statistics were used to determine patterns of segregation in host use. Rather than innate preferences for host species, host use by kissing-bugs is influenced by the habitats they colonise. One of the major limitations of studies on kissing-bug foraging has been the exclusive focus on the dominant vector species. We propose that expanding foraging studies to consider the community of vectors will substantially increase the understanding of Chagas disease transmission ecology. Our results indicate that host accessibility is a major factor that shapes the blood-foraging patterns of kissing-bugs. Therefore, from an applied perspective, measures that are directed at disrupting the contact between humans and kissing-bugs, such as housing improvement, are among the most desirable strategies for Chagas disease control.

Assay of photoinhibition and heat inhibition of photosystem II in higher plants

When thylakoids of higher plant chloroplasts are exposed to excessive light or moderate heat stress, photosystem II reaction center-binding protein D1 is damaged. The photodamage of the D1 protein is caused by reactive oxygen species, mostly singlet oxygen, and also by endogenous cationic radicals generated by the photochemical reactions of photosystem II. Moreover, it was shown recently that the damage to the D1 protein by moderate heat stress is due to reactive oxygen species produced by lipid peroxidation near photosystem II. To maintain photosystem II activity, the oxidatively damaged D1 protein must be replaced by a newly synthesized copy, and thus degradation and removal of the photo- or heat-damaged D1 protein are essential for maintaining the viability of photosystem II. In this chapter, we describe the methods for assaying photoinhibition and heat inhibition of photosystem II in higher plant materials.

Quality control of photosystem II: FtsH hexamers are localized near photosystem II at grana for the swift repair of damage

The reaction center-binding D1 protein of Photosystem II is oxidatively damaged by excessive visible light or moderate heat stress. The metalloprotease FtsH has been suggested as responsible for the degradation of the D1 protein. We have analyzed the distribution and subunit structures of FtsH in spinach thylakoids and various membrane fractions derived from the thylakoids using clear native polyacrylamide gel electrophoresis and Western blot analysis. FtsH was found not only in the stroma thylakoids but also in the Photosystem II-enriched grana membranes. Monomeric, dimeric, and hexameric FtsH proteases were present as major subunit structures in thylakoids, whereas only hexameric FtsH proteases were detected in Triton X-100-solubilized Photosystem II membranes. Importantly, among the membrane fractions examined, hexameric FtsH proteases were most abundant in the Photosystem II membranes. In accordance with this finding, D1 degradation took place in the Photosystem II membranes under light stress. Sucrose density gradient centrifugation analysis of thylakoids and the Photosystem II membranes solubilized with n-dodecyl-β-d-maltoside and a chemical cross-linking study of thylakoids showed localization of FtsH near the Photosystem II light-harvesting chlorophyll-protein supercomplexes in the grana. These results suggest that part of the FtsH hexamers are juxtapositioned to PSII complexes in the grana in darkness, carrying out immediate degradation of the photodamaged D1 protein under light stress.

Regulation of muscle genes by moderate exercise

Moderate-intensity exercise at the lactate threshold (LT) is considered to be a safe and effective training regimen for improving metabolic syndrome. The aim of the current study was to investigate the effects of moderate exercise performed at the LT on skeletal muscle gene expression. 6 healthy men participated in cycle ergometer training at LT, 60 min/d, 5 d/wk for 12 wks. Muscle samples were collected after 5 d of training, and then 2 d after training at wks 6 and 12. Quantitative real-time PCR analysis revealed that the expression of peroxisome proliferator activated receptor co-activated 1alpha was significantly increased at 1 h after the training session on day 5. Moreover, using serial analysis gene expression, we found that moderate training for 6 and 12 wks simultaneously induced the expression of a number of metabolic genes involved in the TCA cycle, beta-oxidation, and electron transport. Furthermore, several genes encoding antioxidant enzymes and contractile apparatus were induced. The expression levels of 233 novel transcripts were also altered in response to moderate exercise. Thus, moderate training at the LT is a sufficient stimulus to induce the expression of numerous genes implicated in the development of metabolic syndrome, transcripts involved in the contractile apparatus, and novel transcripts.

Acute salinity challenges in Mozambique and Nile tilapia: differential responses of plasma prolactin, growth hormone and branchial expression of ion transporters

The responses of Mozambique and Nile tilapia acclimated to fresh water (FW) and brackish water (BW; 17 per thousand) were compared following acute salinity challenges. In both species, plasma osmolality increased to above 450 mOsm by 2h after transfer from FW to seawater (SW); these increases in osmolality were accompanied by unexpected increases in plasma prolactin (PRL). Likewise, PRL receptor gene expression in the gill also increased in both species. In Nile tilapia, hyperosmotic transfers (FW to BW and SW) resulted in increased plasma growth hormone (GH) and in branchial GH receptor gene expression, responses that were absent in Mozambique tilapia. Branchial gene expression of osmotic stress transcription factor 1 (OSTF1) increased in both species following transfer from FW to SW, whereas transfer from BW to SW induced OSTF1 expression only in the Nile tilapia. Branchial expression of Na(+)/Cl(-) cotransporter was higher in FW in both species than in BW. Branchial gene expression of Na(+)/K(+)/2Cl(-) cotransporter (NKCC) increased after transfer from BW to SW in Mozambique tilapia, whereas expression was reduced in the Nile tilapia following the same transfer. The difference in the SW adaptability of these species may be related to a limited capacity of Nile tilapia to up-regulate NKCC gene expression, which is likely to be an essential component in the recruitment of SW-type chloride cells. The differential responses of GH and OSTF1 may also be associated with the disparate SW adaptability of these two tilapiine species.

Effects of mechanical stimuli on the synthesis of superficial zone protein in chondrocytes

Superficial zone protein (SZP) has been demonstrated to contribute to the boundary lubrication in synovial joints. This study was designed to clarify the modulation of SZP expression by mechanical stress in articular chondrocytes. Cyclic tensile strains of 7 and 21% cell elongation were applied to cultured chondrocytes obtained from porcine mandibular condylar cartilage. The mRNA levels of SZP, IL-1 beta, and TGF-beta1 were examined by a quantitative real-time PCR analysis. Protein level of SZP was examined by Western blotting. The SZP mRNA level was significantly upregulated after 12, 24, and 48 h by 7% elongation. Although SZP mRNA level was upregulated by 21% elongation after 12 h, it decreased to a lower level than the control after 48 h. The TGF-beta1 mRNA level exhibited an almost similar change to SZP. The IL-1 beta mRNA level was not changed markedly by 7% elongation. However, the IL-1 beta mRNA level was significantly increased by a 12-h application of 21% elongation. Western blot analysis revealed that the SZP expression was increased by 7% elongation, but decreased remarkably by 21% elongation. It is suggested from these findings that the SZP expression level in the chondrocytes is enhanced by optimal mechanical stimuli, but inhibited by excessive loading partly affected by TGF-beta1 and IL-1 beta, leading to the deterioration of joint lubrication.