Secretory vesicle docking to the plasma membrane: molecular mechanism and functional significance

In regulated exocytic pathways, secretion occurs only in the presence of appropriate stimuli. Professional secretory cells harbour specific storage organelles that release bioactive substances with both controlled timing and quantity in response to the strength and period of stimulation. Although each secretory organelle is highly differentiated in multicellular organisms, the basic regulatory mechanism is thought to be conserved. In most instances, the secretagogue increases the intracellular Ca(2+) concentration from the resting level of approximately 100 nM to somewhere between approximately 10 and 100 microM. Although Ca(2+) sensors of the final fusion reaction, such as synaptotagmin, have been investigated intensively in synaptic vesicle exocytosis, there are other preceding rate-limiting steps influenced by Ca(2+) and other secretory signals, especially in the exocytosis of secretory granules whose time course is much slower than that of synaptic vesicles. The stable docking of secretory vesicles to the fusion site that is only seen in regulated exocytic pathways may represent one such critical step. Here, we review the molecular mechanism of docking, mainly based on recent findings on insulin granules in pancreatic beta cells, and propose a new concept for its functional significance in regulated exocytosis.

Antibacterial Activity and Shear Bond Strength of 4-Methacryloxyethyl Trimellitate Anhydride/Methyl Methacrylate-Tri-n-butyl Borane Resin Containing an Antibacterial Agent

OBJECTIVE

To produce an antibacterial adhesive for orthodontic bonding without compromising the mechanical property.

MATERIALS AND METHODS

We added benzalkonium chloride (BAC) to the Superbond C&B (4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane [4-META/MMA-TBB]), a resin that exhibits a strong bonding strength between enamel and bracket. BAC concentrations in the BAC composites were 0.25%, 0.75%, 1.25%, 1.75%, 2.5%, and 5% (wt/wt). Antibacterial activity of the BAC composite was measured by the disk diffusion method. BAC-composite discs were placed on the surface of the agar inoculated with Streptococcus mutans and Streptococcus sobrinus, and the plates were incubated at 37 degrees C. After 48 hours of incubation, the inhibition zone around each sample was measured and recorded. The BAC-modified composite was used to bond metal brackets to the phosphoric acid-etched enamel surface of human premolars. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours.

RESULTS

The BAC-composite samples showed significant (P < .0001) antibacterial activity compared with the control. Measurable zones of bacterial inhibition increased as the BAC content in test samples increased. The shear bond strength declined with the increase in BAC concentration in the composite. A significant difference was found between the control composite and composites containing 1.25%, 1.75%, 2.5%, and 5% BAC (P < .05). No significant difference was found between the control composite and composites containing 0.25% and 0.75% BAC. However, shear bond strengths of the modified composites ranged from 10.12 MPa to 20.94 MPa.

CONCLUSIONS

These results confirmed that BAC-modified 4-META/MMA-TBB resin has a possibility for clinical application as an orthodontic bonding adhesive.

Effects of aging on RANKL and OPG levels in gingival crevicular fluid during orthodontic tooth movement

OBJECTIVES

To compare the levels of the receptor activator of NFkB ligand (RANKL) and osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic tooth movement in juvenile and adult patients.

DESIGN

Fifteen juveniles and 15 adults served as subjects. GCF was collected from the distal cervical margins of the experimental and control teeth at 0, 1, 24, and 168 h after application of a retracting force. Enzyme-linked immunosorbent assay kits were used to determine RANKL and OPG levels in the GCF samples.

RESULTS

The amount of tooth movement for juveniles was larger than for adults after 168 h. Further, after 24 h RANKL levels were increased and those of OPG decreased in GCF samples from the compression side during orthodontic tooth movement in both juveniles and adults. The RANKL/OPG ratio in GCF from adult patients was lower than that in the juvenile patient samples.

CONCLUSION

Our results suggest that the age-related decrease in amount of tooth movement may be related to a decrease in RANKL/OPG ratio in GCF during the early stages of orthodontic tooth movement.

Modification of 4-META/MMA-TBB resin for safe debonding of orthodontic brackets--influence of the addition of degradable additives or fluoride compound

The purpose of this study was to evaluate the performance of modified 4-META/MMA-TBB resin cements (Superbond C&B) in terms of debonding orthodontic brackets easily and safely from enamel without the loss of proper bracket bond strength. Poly (DL-lactide-co-glycolide) (PLGA), calcium fluoride (CaF2), or alpha-tricalcium phosphate (alpha-TCP) was added to the polymer powder of 4-META/MMA-TBB resin, and the shear bond strength of orthodontic brackets to human enamel using modified resins was measured before and after 10,000-cycle thermal cycling test between 5 degrees C and 55 degrees C. The modified resins tended to provide lower bond strength compared with the original 4-META/MMA-TBB resin. However, alpha-TCP- or CaF2-modified resin showed no significant differences in bond strength before and after thermal cycling. Moreover, there was a tendency of more residual resin remaining on the tooth surface after debonding, thereby suggesting a lower risk of enamel fracture. In conclusion, alpha-TCP- or CaF2-modified 4-META/MMA-TBB resin seemed to allow easy and safe debonding of orthodontic brackets without loss of proper bracket bond strength.

RANKL increase in compressed periodontal ligament cells from root resorption

The ligand receptor activator of NFkappaB (RANKL) plays an important role in osteoclast formation. However, very little is known about the relationship between external apical root resorption during orthodontic treatment and RANKL. We hypothesized that compressive force is responsible for RANKL formation and up-regulation of osteoclastogenesis in periodontal ligament (PDL) cells from patients with severe orthodontically induced external apical root resorption. RANKL and osteoprotegerin (OPG) production, TRAP-positive cells, and resorptive pits were determined. The increase of RANKL and the decrease of OPG were greater in the severe root resorption group than in the non-resorption group. The numbers of TRAP-positive cells and resorptive pits were also increased in the severe root resorption group than in the non-resorption group. These results support the hypothesis that the compressed PDL cells obtained from tissues with severe external apical root resorption may produce a large amount of RANKL and up-regulate osteoclastogenesis.

Imaging immediate-early and strict-late promoter activity during oncolytic herpes simplex virus type 1 infection and replication in tumors

An increasing number of oncolytic viruses have been developed and studied for cancer therapy. In response to needs for non-invasive monitoring and imaging of oncolytic virotherapy, several different approaches, including a positron emission tomography-based method, a method using secreted marker peptides, and optical imaging-based methods, have been reported. Among these modalities, we utilized the luciferase-based bioluminescent assay/imaging systems to determine the kinetics and dynamics of a productive viral infection. The replication cycle of herpes simplex virus type 1 (HSV-1) is punctuated by a temporal cascade of three classes of viral genes: immediate-early (IE), early (E) and late (L) genes. U(L)39- and gamma(1)34.5-deleted, replication-conditional HSV-1 mutants that express firefly luciferase under the control of the IE4/5 or strict-late gC promoters were generated. These oncolytic viruses were examined in cultured cells and a mouse tumor model. IE promoter- and strict-late promoter-mediated luciferase expression was confirmed to indicate viral infection and replication, respectively. Incorporation of a strict-late promoter-driven luciferase cassette into oncolytic HSV-1 vectors would be useful for assessing tumor oncolysis in preclinical tumor treatment studies.

Fluorescence X-ray absorption spectroscopy using a Ge pixel array detector: application to high-temperature superconducting thin-film single crystals

A Ge pixel array detector with 100 segments was applied to fluorescence X-ray absorption spectroscopy, probing the local structure of high-temperature superconducting thin-film single crystals (100 nm in thickness). Independent monitoring of pixel signals allows real-time inspection of artifacts owing to substrate diffractions. By optimizing the grazing-incidence angle theta and adjusting the azimuthal angle phi, smooth extended X-ray absorption fine structure (EXAFS) oscillations were obtained for strained (La,Sr)2CuO4 thin-film single crystals grown by molecular beam epitaxy. The results of EXAFS data analysis show that the local structure (CuO6 octahedron) in (La,Sr)2CuO4 thin films grown on LaSrAlO4 and SrTiO3 substrates is uniaxially distorted changing the tetragonality by approximately 5 x 10(-3) in accordance with the crystallographic lattice mismatch. It is demonstrated that the local structure of thin-film single crystals can be probed with high accuracy at low temperature without interference from substrates.

Substance P stimulates release of RANKL via COX-2 expression in human dental pulp cells

OBJECTIVE

Our previous study found that substance P (SP), a sensory neuropeptide, was expressed in the dental pulp of rats during experimental tooth movement. We examined the effects of SP on the production of prostaglandin (PG) E2 and the receptor activator of nuclear factor- B ligand (RANKL) by human dental pulp fi broblast-like (HDPF) cells.

MATERIALS AND METHODS

SP was added to cultured HDPF cells at concentrations ranging from of 10(-4) to 10(-12) mol/L. PGE2 and soluble RANKL (sRANKL) levels were determined using enzyme-linked immunosorbent assay kits. Gene expression was confi rmed by RT-PCR analysis. Pit formation assays using dentin slices were carried out to examine the effect of SP on osteoclastogenesis.

RESULTS

The levels of PGE2 and sRANKL increased in the presence of SP, though the increases were greater in the experimental groups in both a time- and concentration-dependent manner, and the increase of RANKL was partially mediated by PGE2. The gene expression of cyclooxygenase (COX)-2 and RANKL was up-regulated, and conditioned medium samples obtained from HDPF cells treated with SP induced bone resorption.

CONCLUSIONS

SP stimulated the production of PGE2 and RANKL, and promoted bone resorption. Therefore, SP may be involved in pulpal inflammation and root resorption during orthodontic tooth movement.

Epidermal growth factor receptor mutations and gene amplification in Japanese non-small cell lung cancer patients treated with gefitinib

17063

Background: To evaluate relationship between epidermal growth factor receptor (EGFR) gene status and clinical outcome in patients with non-small-cell lung cancer (NSCLC) treated with gefitinib. Also, to examine an involvement of human papilloma virus (HPV) in EGFR status of these patients. Methods: Twenty seven patients with NSCLC who had relapsed after surgery and received gefitinib were included. Genomic DNA was extracted from the 12 paraffin and the 15 frozen surgical specimens. PCR and sequencing for genotyping were done for EGFR (exon 18–21) and ERBB2 (exon 19–22) and KRAS (exon 1). Gene amplification for EGFR was analyzed by quantitative real-time PCR. HPV was detected by PCR and in-situ PCR. Results: Nine patients (33%) had EGFR mutations; seven patients had deletion mutations in exon 19, one patient had missense mutations (L858R) in exon 21. Two patients had missense mutations (G719S, exon 18 and L838P, exon 21) No mutations were identified in ERBB2 and KRAS. EGFR copy number in the tumor cells ranged from 1.1 to 9.7, and increased EGFR copy numbers (≥3) were observed in six patients ( 22.2%). Two patients (7%) had HPV, and had no mutation and no amplification. Response rate (67% {six of nine patients} v 18% {three of 17 patients}; p = 0.012) was significantly better in patients with EGFR mutations than in patients with wild-type EGFR. Overall survival (median 17 v 9 months) was better in patients with EGFR mutations than in patients with wild-type EGFR. EGFR copy number and presence of HPV were not associated with clinical outcome. Conclusions: EGFR mutations were significantly associated with better clinical outcome in gefitinib treated NSCLC patients.

No significant financial relationships to disclose.

Levels of RANKL and OPG in gingival crevicular fluid during orthodontic tooth movement and effect of compression force on releases from periodontal ligament cells in vitro

OBJECTIVE

To determine the levels of the receptor activator of NFkB ligand (RANKL) and osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic tooth movement. A second objective was to investigate the effect of compression force on RANKL and OPG production from human periodontal ligament (hPDL) cells.

DESIGN

Ten adolescent patients were included. GCF was collected at the distal cervical margins of the experimental and control teeth 0, 1, 24, and 168 h after the retracting force was applied. Thisin vitro study was performed to examine the secretion of RANKL and OPG from hPDL cells following a compression force (0, 0.5, 1.0, 2.0, or 3.0 g/cm(2) for 48 h). Enzyme-linked immunosorbent assay (ELISA) kits were used to determine RANKL and OPG levels in the GCF and the conditioned medium.

RESULTS

GCF levels of RANKL were significantly higher, and the levels of OPG significantly lower, in the experimental canines than in the control teeth at 24 h, but there were no such significant differences at 0, 1, or 168 h. In vitro study indicated that the compression force significantly increased the secretion of RANKL and decreased that of OPG in hPDL cells in a time- and force magnitude-dependent manner. The compression-stimulated secretion of RANKL increased approximately 16.7-fold and that of OPG decreased 2.9-fold, as compared with the control.

CONCLUSIONS

The results obtained suggest that the changes of amount of RANKL and OPG may be involved in bone resorption as a response to compression force.

Low-energy irradiation stimulates formation of osteoclast-like cells via RANK expression in vitro

Low-energy laser irradiation (Ga-Al-As semiconductor laser, output 50 mW) was applied to rat osteoclast precursor cells for 1, 3, 6, or 10 min at 24-h intervals during the culture period. The number of tartrate-resistant acid phosphatase positive multinucleate cells was increased by approximately 1.3-fold in the 3- and 6-min irradiation groups. Further, osteoclasts appeared on day 2 in the laser irradiation groups but not until day 3 in the control groups. In immunohistochemical staining for receptor activator of NF-kappaB (RANK), the laser irradiation groups showed significantly greater amounts of staining in comparison with the control group on days 2 and 3. Reverse transcription-polymerase chain reaction results also showed that the expressions of RANK were upregulated. In the pit formation assay, resorption pits were significantly more abundant in the laser irradiation groups than in the controls. The present results suggest that low-energy laser irradiation facilitates differentiation and activation of osteoclasts via RANK expression.

Shear bond strength of calcium phosphate ceramic brackets to human enamel

The aim of this study was to examine the shear bond strength between Hyaline brackets, a new type of calcium phosphate ceramic bracket, and human enamel using various types of adhesive resin and to investigate the effectiveness of a silane-coupling agent to bond Hyaline to human enamel. Kurasper F, Light Bond, Super Bond C&B, and Transbond XT were used as adhesive resins, and Porcelain Liner M was used as the silane-coupling agent. The Hyaline bracket was bonded to human enamel using one of the above adhesive resins according to the manufacturer's instructions. After applying the Porcelain Liner M to Hyaline, the Hyaline bracket was also bonded to enamel using one of the above adhesive resins according to the manufacturer's instructions. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours. Three types of adhesive resin, Kurasper F, Light Bond, and Super Bond C&B, produced clinically acceptable shear bond strength with and without Porcelain Liner M. Transbond XT produced significantly lower bond strength to enamel with or without Porcelain Liner M (P < .05). The application of Porcelain Liner M was not useful for improving the bond strength of Hyaline to enamel. The adhesive remnant indices were not significantly different among four adhesive resins. In conclusion, adhesive resins such as Kurasper F, Light bond, and Super Bond C&B are useful for bonding esthetic Hyaline brackets to human enamel.

Relationship between substance P and interleukin-1beta in gingival crevicular fluid during orthodontic tooth movement in adults

Metabolism by peptidases plays an important role in modulating the levels of biologically-active neuropeptides, while that of substance P (SP), a component of gingival crevicular fluid (GCF), may potentiate the inflammatory process in orthodontic tooth movement. The aim of this study was two-fold: (1) to investigate GCF levels of SP and interleukin-1beta (IL-1beta) during human orthodontic tooth movement, and (2) to determine the correlation coefficients between SP and IL-1beta levels in the GCF. The subjects were 3 males, with a mean age of 21.3 +/- 2.8 years old, and 6 females, with a mean age of 23.1 +/- 2.4 years, undergoing orthodontic movement of a single tooth, with the contralateral tooth used as the control. GCF was sampled at the control and treatment (compression) sites before and 1, 4, 8, 24, 72, 120, and 168 hours after initiation of orthodontic treatment. Prevention of plaque-induced inflammation allowed assessment of the dynamics of mechanically stimulated SP and IL-1beta levels in the GCF, which were determined using enzyme-linked immunosorbent assay (ELISA) kits. GCF levels of SP and IL-1beta for the treated teeth were significantly higher (P < 0.001) than for the corresponding control teeth from 8 to 72 hours, and peaked at 24 hours. These results show that the amounts of SP and IL-1beta in GCF increase with orthodontic tooth movement, and indicate that such increases may be involved in inflammation in response to mechanical stress.

Relationship between masticatory function and internal structure of the mandible based on computed tomography findings

INTRODUCTION

The purposes of this study were to investigate bone mineral density as a part of bone construction in human skulls and to examine the relationship between dentofacial morphology and masticatory function by using computed tomography (CT) findings. Changes in bone mineral density in the mandible because of loss of masticatory function were tested in rats by experimentally producing an environment that inhibited mastication by the molars.

METHODS

Data for the human study were obtained from 27 modern male Japanese skulls (mean age, 28 years) from the University of Tokyo. Cortical bone thickness (CBT) and CT value (CV) were measured by each CT scan of the first and molars. For the animal study, a metal cap was inserted between the maxillary and mandibular incisors to prevent the molars from biting in 6-week-old male Wistar rats. The rats were killed after 2, 4, or 6 weeks, and bone mineral density was measured in cancellous and cortical bone equivalent to the first molar region by using peripheral quantitative computed tomography.

RESULTS

In the human skull study, significant negative correlations were observed between CV in the regions of the buccal side of the second molar and the angle between the Frankfort horizontal and mandibular planes. Significant negative correlations were also observed between the gonial angle and CV in the buccal and basal sides. In the animal study, cancellous bone mineral density began to decline 4 weeks after the start of the experiment in the masticatory hypofunction group compared with the control group. By week 6, cancellous bone density had declined by 11.6% on the buccal side, 16.7% on the lingual side, 12.3% at the bifurcation of the root, and 38.1% at the root apex. Cortical bone density declined by 8% to 12% on the lingual side.

CONCLUSIONS

The results support our hypothesis that a functional adaptive response by the mandible to mechanical stress resulting from mastication occurs not only in the muscle insertion area, but also in mandibular alveolar bone in the molar region.

External validation of the biodegradability prediction model CATABOL using data sets of existing and new chemicals under the Japanese Chemical Substances Control Law

External validation of the biodegradability prediction model CATABOL was conducted using test data of 338 existing chemicals and 1123 new chemicals under the Japanese Chemical Substances Control Law. CATABOL predicts that 1089 chemicals will have a BOD < 60% while 925 (85%) actually have an observed BOD<60%. The percentage of chemicals with an observed BOD value <60% tends to increase as the predicted BOD values decrease. In contrast, 340 chemicals were predicted to have a BOD > or = 60% and 234 (69%) actually had an observed BOD > or = 60%. The prediction of poor biodegradability was more accurate than the predictions of high biodegradability. The features of chemical structures affecting CATABOL predictability were also investigated.

Inflammation in periodontal tissues in response to mechanical forces

Orthodontic forces are known to produce mechanical damage and inflammatory reactions in the periodontium and dental pulp, as well as inflammatory mediators, e.g. prostaglandins, interleukin (IL)-1, IL-6, tumor necrosis factor alpha, and receptor activator of nuclear factor kappaB ligand, in the periodontal ligament (PDL) and dental pulp. We have studied the effects of aging on the production of inflammatory mediators in the PDL using in vitro and in vitro methods and found that aging of PDL tissues may be an important factor in the severity of periodontal disease through a higher production of inflammatory mediators in response to mechanical forces. Further, the levels of inflammatory mediators in gingival crevicular fluid, an osmotically mediated inflammatory exudates found in the gingival sulcus, have been shown to be significantly elevated during orthodontic treatment. In order to reduce inflammation, low-level laser therapy has been recently studied in vitro and in vitro by many investigators as a substitute for anti-inflammatory drugs. Clinical and experimental studies have shown that low-level laser irradiation reduces orthodontic post-adjustment inflammation. We believe that orthodontic forces (mechanical forces) may play an important role in periodontal inflammation and that low-level laser therapy may be useful for its inhibition.

Bonding durability of using self-etching primer with 4-META/ MMA-TBB resin cement to bond orthodontic brackets

This study determines the bonding durability when a self-etching primer is used with Superbond C&B (a 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butyl borane resin) to bond orthodontic brackets to enamel. Thermocycling test was used to assess bonding durability. Metal brackets were bonded to the phosphoric acid-etched or Megabond self-etching primer-treated enamel surface of human premolars using Superbond C&B. The shear bond strengths were measured after immersion in water at 37 degrees C for 24 hours or after 2000 or 5000 cycles of thermocycling between 5 degrees C and 55 degrees C. Data were analyzed using 2-way analysis of variance and Fisher's protected least significant difference test for multiple comparisons. There was no significant difference in shear bond strength between phosphoric acid and Megabond self-etching primer treatment before the thermocycling test. After 2000 and 5000 thermal cycles, significant decreases in shear bond strength were observed with phosphoric acid etching. On the contrary, no significant differences in shear bond strength were observed after 2000 and 5000 thermal cycles with Megabond self-etching primer. The adhesive remnant indices were not significantly different between phosphoric acid etching and Megabond self-etching primer treatment either before or after thermal cycles. This study suggested that when used with Superbond C&B in bonding orthodontic brackets, Megabond self-etching primer is superior to phosphoric acid as an enamel preparation agent in providing durable bond strength.

Simultaneous visualization of rDNA clusters and the nucleolus by combining fluorescence in situ hybridization and silver staining

We designed two procedures to visualize simultaneously clusters of ribosomal RNA genes (rDNA) and the nucleolus in plant cells. The procedures combine fluorescence in situ hybridization (FISH) to visualize the rDNA clusters and silver staining to observe the nucleolus. When FISH is followed by silver staining, many minute FISH signals are localized in the nucleolus, and several large FISH signals are seen on the nucleolar periphery. When FISH was applied to the specimens with silver nitrate staining, large FISH signals were visualized in the nucleoplasm associated with the nucleolar periphery, but no signals were seen in the nucleoli. Thus, the two combinations of FISH and silver staining provided different details regarding the arrangement of rDNA clusters in the nucleolus of plant cells.

Angiotensin-II-induced oxidative stress elicits hypoadiponectinaemia in rats

AIMS/HYPOTHESIS

Hypertension, endothelial dysfunction and insulin resistance are associated conditions that share oxidative stress and vascular inflammation as common features. Adiponectin is an abundant plasma adipokine that plays a physiological role in modulating lipid metabolism and exerts a potent anti-inflammatory activity. We hypothesised that adiponectin levels decrease in response to oxidative stress and that this may promote the development of hypertension, endothelial dysfunction and insulin resistance.

METHODS

Rats were infused with angiotensin II (AngII) or its vehicle, either alone or in combination with tempo1 (4-hydroxy-2,2,6,6-tetramethyl piperidinoxyl), a membrane-permeable metal-independent superoxide dismutase mimetic, or tetrahydrobiopterin (BH4), one of the most potent naturally occurring reducing agents and an essential cofactor for nitric oxide synthase activity. Heart rate, systolic blood pressure, body weight and serum levels of adiponectin were measured on day 7 of treatment, and then the animals were killed. Vessel tone and superoxide production were measured ex vivo in thoracic vascular rings. The expression of adiponectin mRNA in adipose tissue was assessed by Northern blotting, and in 3T3-L1 adipocytes exposed to H2O2 by real-time PCR. The expression of NAD(P)H oxidase subunit mRNAs in the rats was assessed by RT-PCR and real-time PCR.

RESULTS

Hypertension and endothelial dysfunction were induced in rats by infusion of AngII and reversed by administration of tempol. Plasma concentrations of adiponectin and adipose tissue levels of adiponectin mRNA were decreased in AngII-infused rats, and this effect was prevented by cotreatment with tempol or BH4. The production of superoxide anions (O2-) was significantly increased in the aortae of AngII-treated rats, and this increase was prevented by the administration of tempol or BH4. Levels of mRNAs that encode NAD(P)H oxidase components, including p22phox, gp91phox, p47phox and Rac1, were similarly increased in adipose tissue, aortae and hearts of AngII-infused rats. Cotreatment of rats with tempol or BH4 reversed AngII-induced increases in NAD(P)H oxidase subunit mRNAs. Fully differentiated 3T3-L1 adipocytes, also exhibited diminished adiponectin mRNA levels when exposed to low concentrations of H2O2.

CONCLUSIONS/INTERPRETATION

Our results demonstrate that AngII-induced oxidative stress and endothelial dysfunction are accompanied by a decrease in adiponectin gene expression. Since antioxidants were observed to prevent the actions of AngII, and H2O2 on its own suppressed adiponectin expression, we conclude that adiponectin gene expression is negatively modulated by oxidative stress. Plasma adiponectin levels may provide a useful indicator of oxidative stress in vivo, and suppressed levels may contribute to the proinflammatory and metabolic derangements associated with type 2 diabetes, coronary artery disease and the metabolic syndrome.

Levels of t-PA and PAI-2 in gingival crevicular fluid during orthodontic tooth movement in adults

BACKGROUND

The regulation of plasminogen activation is a key element in controlling proteolytic events in the extracellular matrix.

OBJECTIVE

The aim of this study was to investigate gingival crevicular fluid (GCF) levels of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI -2) during orthodontic tooth movement in adults.

METHODS

Five male subjects (Mean age: 22.5 +/- 2.8 years) and five female subjects (Mean age: 23.4 +/- 3.9 years) were used. Each subject had one upper canine retracted into an extraction space. The contralateral and opposing canines, which were not moved, served as controls. GCF was collected at the distal cervical margins of the experimental and control teeth 0, 1, 24, and 168 hours after a retracting force was placed. GCF levels of t-PA and PAI-2 were determined by commercially available ELISA kits.

RESULTS

After 24 hours of tooth movement the levels of t-PA and PAI-2 in the GCF were significantly higher from the experimental canines compared with the control teeth. There were no significant experimental-control differences at 0, 1, and 168 hours. There were no differences in the total protein levels up to 168 hours after orthodontic tooth movement.

CONCLUSIONS

These results indicate that the amounts of t-PA and PAI-2 in the GCF increase with orthodontic tooth movement, and suggest that such increases may be involved in extracellular matrix degradation in response to mechanical stress. Failure to detect elevated levels of t-PA and PAI-2 at 168 hours was attributed to decay of the force retracting the canines.