Modulating stemness of mesenchymal stem cells from exfoliated deciduous and permanent teeth by IL-17 and bFGF.

Mesenchymal stem cells (MSCs) have been identified within dental pulp tissues of exfoliated deciduous (SHEDs) and permanent (DPSCs) teeth. Although differences in their proliferative and differentiation properties were revealed, variability in SHEDs and DPSCs responsiveness to growth factors and cytokines have not been studied before. Here, we investigated the influence of interleukin-17 (IL-17) and basic fibroblast growth factor (bFGF) on stemness features of SHEDs and DPSCs by analyzing their proliferation, clonogenicity, cell cycle progression, pluripotency markers expression and differentiation after 7-day treatment. Results indicated that IL-17 and bFGF differently affected SHEDs and DPSCs proliferation and clonogenicity, since bFGF increased proliferative and clonogenic potential of both cell types, while IL-17 similarly affected SHEDs, exerting no effects on adult counterparts DPSCs. In addition, both factors stimulated NANOG, OCT4, and SOX2 pluripotency markers expression in SHEDs and DPSCs showing diverse intracellular expression patterns dependent on MSCs type. As for the differentiation capacity, both factors displayed comparable effects on SHEDs and DPSCs, including stimulatory effect of IL-17 on early osteogenesis in contrast to the strong inhibitory effect showed for bFGF, while having no impact on SHEDs and DPSCs chondrogenesis. Moreover, bFGF combined with IL-17 reduced CD90 and stimulated CD73 expression on both types of MSCs, whereas each factor induced IL-6 expression indicating its' role in IL-17/bFGF-modulated properties of SHEDs and DPSCs. All these data demonstrated that dental pulp MSCs from primary and permanent teeth exert intrinsic features, providing novel evidence on how IL-17 and bFGF affect stem cell properties important for regeneration of dental pulp at different ages.

Analysis and prevention of ergonomic risk factors among dental students.

INTRODUCTION: Dentistry is a high-risk profession for the development of work-related disorders. Dental students are also exposed to several risk factors. The goal of the study was to determine and localise musculoskeletal pain during dental work, afterwards to measure electromyography signals from the muscles groups mostly affected by the musculoskeletal pain. Study was done in order to provide possible suggestions for the most effective preventive measures of MS pain among dental students. MATERIALS AND METHODS: In order to solve the objectives, the research was realised in two segments. In the first part of the study, specially designed questionnaires were used to determine the frequency of musculoskeletal pain, risk factors and preventive measures among students. The second part of the study included electromyography analyses of muscular activity of students during dental work. Inclinometers also were set up in the purpose of monitoring inclination of the spine. RESULTS: Results of the questionnaire study indicated that pain during work was frequent, 81.8% of all the subjects reported pain during work. The recorded muscle activity of the neck muscles indicated a high ergonomic risk, while the muscle activity of the shoulders and back muscles indicated a medium risk. Work with a back flexion of 20 degrees and more indicates that students are at risk. CONCLUSION: Dental students used to work in unnatural working position. High ergonomic risk occurred in neck muscles. Students should be aware of the potential risks during work and to learn how to prevent it. Regular physical activity is strongly suggested to the students in order to avoid ergonomic problems.

Assessment of risk factors and preventive measures and their relations to work-related musculoskeletal pain among dentists.

BACKGROUND: Dentists have a high prevalence of musculoskeletal (MS) pain, which is the most common symptom associated with work-related musculoskeletal disorders (WMSDs). To overcome this problem, identification of the risk factors and preventive measures for MS pain are of paramount importance to dentists in order to improve their quality of life and work. OBJECTIVES: The aims of this study were to recognize the risk factors for MS pain and their impact on dental work, as well as to identify preventive measures of MS pain among dentists. METHODS: Self-reporting questionnaire consisting of 78 questions was exclusively developed for the study and sent to 500 working active dentists in Serbia. RESULTS: Response rate was 71.2% (356 dentists). The prevalence of MS pain was 82.6% among dentists. The main risk factors for MS pain were advanced age, female dentists, presence of chronic diseases, long working hours, and high frequency of treated patients. The most effective preventive measures in preventing MS pain were massage treatments and physical activities. Followed by use of ergonomically designed equipment, correct and dynamic working positions, and an adequate workflow organization. CONCLUSION: The risk factors for MS pain and their impact on dental work should widely be disseminated among dentists. Importantly, proper implementation in everyday life of adequate preventive measures is essential for preventing MS pain and development of WMSDs.

Posture in dentists: Sitting vs. standing positions during dentistry work--An EMG study.

INTRODUCTION: Adequate working posture is important for overall health. Inappropriate posture may increase fatigue, decrease efficiency, and eventually lead to injuries. OBJECTIVE: The purpose was to examine posture positions used during dentistry work. METHODS: In order to quantify different posture positions, we recorded muscle activity and positions of body segments. The position (inclination) data of the back was used to assess two postures: sitting and standing during standard dental interventions. RESULTS: During standard interventions, whether sitting or standing, a tilt of less than 20 degrees was most prevalent in the forward and lateral flexion directions. Amplitude of electromyography signals corresponding to the level of muscle activity were higher in sitting compared with the electromyography in standing position for all muscle groups on the left and right side of the body. Significant difference between muscle activity in two working postures was evident in splenius capitis muscle on the left (p = 0.032), on the right side of the body (p = 0.049) and in muscle activity of mastoid muscle on the left side (p = 0.029). CONCLUSION: These findings show that risk for increased fatigue and possible injures can be reduced by combining the sitting and standing occupational postures.

Different methods for subgingival application of chlorhexidine in the treatment of patients with chronic periodontitis.

OBJECTIVE: The aim of this study was to evaluate clinical efficacy of different chlorhexidine gluconate (CHX) preparations applied subgingivally as an adjunct to scaling and root planing (SRP). MATERIAL AND METHODS: A total of 120 periodontal pockets was included in this randomized, controlled, split mouth designed study. According to protocols used in treatment, periodontal pockets were assigned to experimental and control groups as follows: CHX solution as an addition to SRP versus control SRP group; CHX gel as an addition to SRP versus control SRP; CHX chip as an addition to SRP versus control SRP group. Following clinical parameters were recorded at baseline, one and three months after the baseline: plaque index (PI), probing pocket depth (PPD), bleeding index (BI) and clinical attachment level (CAL). RESULTS: The most significant improvements were found concerning PI in CHX solution with SRP and CHX gel with SRP groups over controls at one month recall, as well as concerning BI and PPD in CHX chip with SRP group over SRP alone at three-month recall. CONCLUSION: Results of this study favour combination therapy using CHX chip as an adjunct to SRP due to greater improvements in BI and PPD compared to those obtained by SRP alone in the treatment of chronic periodontitis.

Polyinosinic/Polycytidylic Acid-mediated changes in maternal and fetal disposition of lopinavir in rats.

Maintenance of optimal lopinavir (LPV) concentration is essential for effective antiretroviral therapy and prevention of mother-to-child transmission of human immunodeficiency virus. However, little is known about the effects of inflammation on the pharmacokinetics of this protease inhibitor and drug transporter substrate, particularly during gestation. Our objective was to study the effect of polyinosinic/polycytidylic acid [poly(I:C)], a viral mimetic, on key maternal drug transporters, and to examine the effect on maternal and fetal disposition of LPV in rats. Poly(I:C) (5.0 mg/kg i.p.) or saline vehicle was administered to pregnant Sprague-Dawley rats on gestational days 17-18. At 24 hours postinjection, all rats were administered LPV (10 mg/kg i.v.), and plasma and tissues were collected at 5-120 minutes postadministration. Plasma interferon-γ (IFN-γ) levels were measured by enzyme-linked immunosorbent assay, and transporter expression was measured via real-time polymerase chain reaction. Maternal plasma, hepatic, placental, and fetal LPV concentrations were determined by liquid chromatography-tandem mass spectrometry. Administration of poly(I:C) induced IFN-γ plasma levels and downregulated the expression of several important ATP-binding cassette (ABC) drug efflux transporters in the placenta and liver of pregnant rats, compared with controls (P < 0.05). Maternal LPV plasma concentration and area under the concentration-versus-time curve were significantly increased in the poly(I:C) group. Plasma protein binding was also significantly higher in poly(I:C)-treated rats. Pronounced increases in hepatic, placental, and fetal LPV tissue:unbound plasma concentrations were seen in the poly(I:C) group; however, absolute tissue concentrations were not changed. Since the majority of commonly used and clinically important antiretroviral drugs are known to be ABC transporter substrates, inflammation-mediated changes in transporter expression could affect their maternal disposition and fetal exposure.

Maternal bacterial infections impact expression of drug transporters in human placenta.

BACKGROUND: Several efflux and uptake transporters in the placenta are involved in the transmembrane transport of endogenous substrates and xenobiotics. Their expression and function may be altered in maternal complications associated with inflammation. Our objective was to examine the effect of chorioamnionitis, a bacterial intra-amniotic infection on the expression of clinically important transporters in human placenta. METHODS: Human placental samples were collected from preterm and term pregnancies diagnosed with chorioamnionitis infection and were gestational age-matched with samples from pregnancies with no obstetric complications, using predefined exclusion criteria. Transporter protein expression was quantified using Western blots while cytokine and transporter mRNA expression was measured via real-time polymerase chain reaction. RESULTS: mRNA levels of pro-inflammatory cytokines IL-6, IL-1ß and TNF-α were markedly elevated by 2.5- to 3-fold in preterm placentas with infection, relative to preterm controls (p<0.05). Expression of ABCG2 and SLCO2B1 was downregulated by 48 to 57% (p<0.05) in placentas from women with infection and preterm parturition, relative to preterm healthy controls. Protein and mRNA expression changes were generally consistent. At term, ABCG2 mRNA and SLCO2B1 protein expression levels were significantly downregulated, relative to controls. Significant changes in ABCB1 and SLCO4A1 expression were not observed, however ABCB1 transcript levels strongly correlated with IL-6, IL-1ß and TNF-α expression (p<0.001), potentially suggesting involvement of cytokine-mediated regulation. CONCLUSIONS: Collectively, these data show that maternal infections impact the expression of key drug transporters in placenta, suggesting that materno-fetal drug transport may be altered by changes in placental expression of ABC and OATP transporters.

[Oral Health in Children with Asthma].

INTRODUCTION: It has been suggested that asthmatic patients may have a higher risk for oral diseases, both as a result of the medical condition and effects of medications. OBJECTIVE: The aim of the study was to determine the oral health status of children with asthma and to evaluate the oral health parameters according to the medications and severity of the disease. METHODS: The study group consisted of 158 children with asthma and 100 healthy control subjects aged 2-18 years. The diagnosis of dental caries was performed using the Decayed, Missing, and Filled Teeth (DMFT/dmft) criteria. The oral hygiene, periodontal status and gingival health were assessed with the Simplified Oral Hygiene Index (Greene-Vermillion), Community Periodontal Index of Treatment Needs and Gingival Index (Löe-Silness), respectively. RESULTS: Thirty (19%) patients with asthma and 43 (43%) healthy children were caries-free (p<0.001). There were no significant differences between asthmatic and control children in caries experience (for children with asthma mean DMFT=2.1±1.8, mean dmft=4.2±3.3; for healthy children mean DMFT=2.5±0.9, mean dmft=5.2±1.3). Level of asthma control did not have influence on dental health, while dose of inhaled corticosteroid had impact on primary dentition. Periodontal status and gingival health did not differ between asthmatic and control children. However, children with asthma had poorer oral hygiene (p<0.001). CONCLUSION: Results of the study do not show a relationship between asthma and oral diseases. However, further improvement could be made in educating children and parents on the importance of good oral hygiene and prevention of oral diseases.

The influence of different therapeutic modalities and platelet rich plasma on apexogenesis: a preliminary study in monkeys.

BACKGROUND: Traumatic injuries of permanent teeth with incomplete root formation are frequent during childhood. Adequate therapy is important for the further destiny of teeth with damaged pulp. OBJECTIVES: To evaluate the effect of pulpotomy and high pulpotomy on the pulp and on root development, and the effect of platelet rich plasma (PRP) with hydroxyapatite (HAP) as a carrier and hydroxyapatite alone on apexogenesis. MATERIAL AND METHODS: The study included eight monkeys (Cercopithecus aethiops) in which high pulpotomies were performed on the mandibular lateral incisors and canines, and pulpotomies were performed on the mandibular central incisors and premolars. The materials used in the study were commercial HAP (Apatec®, Stomygen) and PRP (prepared at the Torlak Institute of Immunology and Virology, Belgrade, Serbia.). Histological and radiological evaluations were done six months after the treatment. RESULTS: Considering the differences between HAP+PRP treated teeth in the pulpotomy group and teeth in the high pulpotomy group, two times more root growth retardation was observed in the high pulpotomy group. In the high pulpotomy group, root growth retardation was less common in HAP+PRP treated teeth (42.9%) than in HAP treated teeth (50%). In the pulpotomy group, retardation of root development was also less common in HAP+PRP treated teeth (25%) compared to HAP treated teeth (50%). There were differences between the pulpotomy and high pulpotomy groups, but without statistical significance. CONCLUSIONS: The application of endogenous growth factors in conjunction with the preservation of dental pulp vitality can result in a good outcome for pulp therapy of injured teeth, which means successfully completed apexogenesis.

Antioxidative status of saliva before and after non-surgical periodontal treatment.

INTRODUCTION: Oxidative stress and antioxidants play an important role in the pathogenesis of inflammatory disease, including chronic periodontitis (CP). Saliva contains enzymatic (glutathione peroxidase - GPx, superoxide dismutase - SOD, etc.) and non-enzymatic (albumin - ALB, uric acid - UA, glutathione, etc.) antioxidants. OBJECTIVE: The aims of this study were to investigate: a) level of SOD, GPx, UA, ALB and total antioxidative status (TAS) of saliva in CP patients before and after non-surgical treatment, and b) correlations between clinical periodontal parameters and levels of salivary antioxidants. METHODS: Saliva was collected from 21 CP patients before and after non-surgical treatment. The condition of periodontium was assessed by plaque index, gingival index, bleeding on probing, probing depth and clinical attachment loss. Level of investigated antioxidants (except GPx) and TAS was determined using colorimetric method and commercial kits. GPx activity was determined using UV method and commercial kits. RESULTS: After the treatment significant increase of UA, ALB, Gpx, TAS was detected (p<0.01) and decrease of SOD activity (p>0.05). A significant correlation was observed between GPx and PI (r=0.575, p=0.008), SOD and GI (r=0.525, p=0.017) before therapy, and SOD and bleeding on probing (BP) (r=0.59, p=0.006), TAS and BP (r=0.453, p=0.045) after therapy. CONCLUSION: These data suggest that levels of salivary antioxidants generally increase after non-surgical periodontal treatment. Correlation between some clinical periodontal parameters and level of salivary antioxidants was found.

Inflammation-mediated changes in drug transporter expression/activity: implications for therapeutic drug response.

Inflammation plays a critical role in host defense, maintaining cellular and tissue integrity following chemical, physical and biological insults. Inflammation presents in a variety of acute and chronic disease states and can contribute to disease resolution or progression depending upon the type, magnitude and duration of response. Importantly, it has been shown to modulate pharmacokinetic processes leading to variability in therapeutic drug response. Membrane-associated drug transporters are important determinants of drug disposition and pharmacokinetics and we, among others, have identified inflammation-mediated changes in their expression and regulation. Here, we discuss the current state of knowledge on drug transporter expression during acute and chronic inflammatory conditions and postulate how the altered expression of these transporters may modify the pharmacokinetics and pharmacodynamics of clinically important therapeutics. As understanding determinants of interpatient variability in therapeutic drug response is essential to the practice of medicine, this area of research warrants future clinical focus.

Long-term survival in idiopathic pulmonary arterial hypertension associated with massive pulmonary artery dilation.

The present report describes two patients with long-term survival after being diagnosed with idiopathic pulmonary arterial hypertension more than 20 years earlier. Both patients were treated with calcium channel blockers for several years and are currently maintained on bosentan, an oral endothelin receptor antagonist. Severe dilation of the main pulmonary arteries is present in both patients and may be related to long-term survival with idiopathic pulmonary arterial hypertension.

Impact of polyinosinic/polycytidylic acid on placental and hepatobiliary drug transporters in pregnant rats.

Although inflammation is known to impose changes in the expression and activity of drug transporters, little is known about the impact of inflammatory stimuli on these transporters during pregnancy. Our objective was to study the effect of viral-induced inflammation on key maternal hepatic and placental drug transporters and their endogenous substrates. Acute inflammation was induced in pregnant Sprague-Dawley rats (gestation day 17-18, n = 5-6/group) by single intraperitoneal doses of polyinosinic/polycytidylic acid [poly(I:C)] (2.5 or 5.0 mg/kg) with saline as a control. Tissues were harvested 24 h later. Expression of transporters was measured via real-time polymerase chain reaction and Western blotting. Maternal plasma levels of cytokines, bile acids, and bilirubin and fetal levels of bile acids were examined. Plasma concentrations of interferon-γ, tumor necrosis factor-α, and interleukin-6 were significantly induced in poly(I:C)-treated rats, compared with controls (p < 0.001). Significant down-regulation of placental Abcb1a/b, Abcc1, Abcc3, Abcg2, Slco1a4, and Slco4a1 mRNA and of hepatic Abcc2, Abcg2, Slco1a4, Slc10a1, and Cyp3a2 mRNA was observed in poly(I:C)-treated rats. Hepatic Abcb1b and Abcc3 mRNA levels were significantly induced. Hepatic protein levels of P-glycoprotein, multidrug resistance-associated protein 2, and breast cancer resistance protein were significantly down-regulated relative to those for controls (p < 0.05). Total bile acids in maternal plasma were significantly increased at the higher dose of poly(I:C). In summary, the poly(I:C) model of viral infection imposes significant changes in the expression of key drug transporters in placental and hepatic tissues of pregnant rats. Because many clinically important endogenous and exogenous compounds are substrates of these transporters, inflammation-mediated changes in transporter expression could affect their maternal disposition and fetal exposure.

[The use of beta-tricalcium phosphate and bovine bone matrix in the guided tissue regeneration treatment of deep infra-bony defects].

INTRODUCTION: The primary goal of bone regeneration procedures with application of various regenerative biologic agents and biomaterials is to facilitate the formation of periodontal tissues lost as a result of periodontitis. OBJECTIVE: The aim of the study was to compare clinical outcome of the guided tissue regeneration (GTR) treatment with the use of beta-tricalcium phosphate and with bovine bone matrix in human deep intra-osseous defects. METHODS: Twenty-one systemically healthy subjects with moderate to advanced periodontitis, between 30 and 56 years of age, 11 females and 10 males, were selected. Patients having two similar inter-proximal defects with pocket probing depths following initial therapy greater than 5 mm were recruited for the study. Experimental sites were grafted with pure beta-tricalcium phosphate biomaterial (Cerasorb) and a biomembrane, while control sites were treated with bovine-bone hydroxiapatite xenograft (Bio-oss) and a biomembrane. Immediately before surgery and 12 months after surgery, pocket probing depth (PPD), epithelial attachment level (EAL) and gingival recession (GR) were evaluated. RESULTS: In the experimental group PPD amounted to 6.76 +/- 0.83 mm before surgery, and decreased significantly to 2.67 +/- 0.48 mm 12 months following surgery, while in the control group PPD significantly decreased from 7.14 +/- 0.65 mm presurgically to 2.85 +/- 0.57 mm postsurgically. After one year, EAL gain was 2.76 +/- 0.99 mm in the experimental group, and 3.24 +/- 0.16 mm in the control group. After twelve months postoperatively GR amounted to 1.33 +/- 0.79 mm in the experimental group and to 1.05 +/- 0.80 mm in the control group. No statistically significant differences for PPD reduction, EAL gain and GR increase were detected between the groups. CONCLUSION: Results from the present study indicate that GTR treatment of deep intra-osseous defects with Bio-oss and Cerasorb resulted in clinically and statistically significant improvement of EAL gain and PPD reduction. A GR was slightly increased, with no statistical significance.

Effect of endotoxin on the expression of placental drug transporters and glyburide disposition in pregnant rats.

On average, 80% of pregnant women consume over-the-counter and/or prescription medications. The placenta is a crucial organ that can restrict fetal drug exposure. ATP-binding cassette (ABC) drug transporters play an important role in the placenta because they limit the transplacental transfer of xenobiotics. However, the impact of infection or inflammation on placental drug transporters is not well established. Thus, we examined the impact of endotox-in-induced inflammation on the placental expression of several key drug transporters in rats and its impact on fetal exposure to a drug substrate. Real-time polymerase chain reaction results demonstrated a significant time- and dose-dependent down-regulation of breast cancer resistance protein/Abcg2 mRNA in the placentas of endotoxin-treated rats with a corresponding decrease in protein levels. Likewise, the mRNA levels of several other ABC transporters (Abcb1a, Abcb1b, Abcc1, Abcc2, Abcc3) and members of the organic anion-transporting polypeptides (Slco1a4, Slco2b1, Slco4a1) were down-regulated. A biodistribution study was carried out with glyburide, a hypoglycemic sulfonylurea substrate of both ABC efflux and Oatp uptake transporters. Although administration of endotoxin resulted in comparable plasma concentrations of glyburide, a pronounced increase in the accumulation of glyburide was seen in the fetuses of endotoxin-treated rats (162% of controls, p < 0.01). Glyburide plasma protein binding was not affected by endotoxin treatment. Overall, our results demonstrated a significant reduction in the placental expression of several important drug transporters during endotoxin-induced inflammation. Alterations in glyburide distribution highlight the potential importance of both influx and efflux placental transporters in impacting fetal drug exposure.

[Histological evaluation of platelet rich plasma and hydroxyapatite in apexogenesis: study on experimental animals].

BACKGROUND/AIM: There are very few data about the effects of endogenous growth factors in vital pulp therapy, and still they are often controversial. The aim of the study was to evaluate the effects of platelet rich plasma (PRP) in conjugation with hydroxyapatite (HAP), as pulp capping materials, to root and periodontium formation. METHODS: Eight young monkeys (Cercopithecus Aethiops) with permanent dentition and incomplete root formation were involved in this study. After pulpotomy, the pulp lesion was capped with calcium hydroxide (control), hydroxyapatite (experimental group I) or hydroxyapatite in conjugation with PRP (experimental group II). Six months later, the animals were sacrificed, the tissue was removed en block, and prepared for the histological analysis in a routine way. RESULTS: The results of the histological analysis revealed that healing process was characterised by dentin bridge formation, maintained morphological and functional integrity of dental pulp and complete formation of dental root and surrounding periodontium. The inflammatory reaction was scored as mild to moderate, in almost all the samples in all groups, suggesting the biocompatibility of the used materials. CONCLUSION: Materials used in this study are convenient as capping agents, contributing maintaining the integrity of the pulp tissue and facilitating root and periodontium forma tion. According to histological data it could be suggested that hydroxyapatite in conjugation with endogenous growth factors, represents superior alternative to other materials used in this study.

Regulation of drug transporters during infection and inflammation.

Inflammation-induced changes in the pharmacokinetics and dynamics of numerous drugs have been reported. Altered drug disposition during inflammatory disease has traditionally been ascribed primarily to changes in drug metabolism and protein binding. Emerging evidence within the last decade, however, has demonstrated that the inflammatory response affects the expression of several important drug transporters and these changes significantly impact the disposition and activity of drug substrates.

How rats process spatiotemporal information in the face of distraction.

How rats process spatiotemporal information in the face of distraction was assessed. Rats were trained on a time-place learning task in which the location of food availability depended on the amount of time elapsed since the beginning of the training session. In each training session each of four levers provided food pellets for 5 min on an intermittent schedule. In probe sessions interspersed with the final training sessions, the rats were presented with a second highly preferred food source-a piece of cheese-at various times into the session. Rats choose the correct lever after the cheese distraction, but it appeared that their internal clock had stopped during the cheese consumption period. Thus rats' internal clock, like that of pigeons, displays the properties of 'stop', 'reset', and 'restart'. Rat-pigeon differences in timing processes may be restricted to circadian or time of day timing. Present results also suggest that rats process spatial and temporal information separately.