Inhibition of Escherichia coli O157:H7 on stainless steel using Pseudomonas veronii biofilms.

We produced a Pseudomonas veronii biofilm on the surface of a stainless steel that is inhibitory to Escherichia coli O157:H7. Pseudomonas veronii strain KACC 81051BP, isolated from lettuce, readily formed biofilm on the surface of stainless steel coupons (SSCs) immersed in tryptic soy broth at 25°C. Cells showed significantly (P ≤ 0·05) enhanced tolerance to desiccation stress (43% relative humidity (RH)) and retained antimicrobial activity against E. coli O157:H7. The number of E. coli O157:H7 (control; 4·1 ± 0·1 log CFU per coupon) on sterile SSCs decreased to 2·7 ± 0·2 log CFU per coupon after exposure to 43% RH at 25°C for 48 h, while the population of E. coli O157:H7 (4·1 ± 0·0 log CFU per coupon) on SSCs containing P. veronii biofilm decreased to below the theoretical detection limit (1·5 log CFU per coupon) within 24 h. The antimicrobial biofilm produced on stainless steel may have application in preventing cross-contamination by E. coli O157:H7 on other abiotic surfaces in food-contact environments. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of Escherichia coli O157:H7 on environmental surfaces of food manufacturing, transportation and storage facilities is a significant food safety concern because it can result in cross-contamination of food products. In this study, we developed a Pseudomonas veronii biofilm on the surface of a stainless steel that inhibits the growth of E. coli O157:H7. Since P. veronii in biofilm resists desiccation, it provides persistent antimicrobial activity. Information presented here provides novel and practical insights to developing biological strategies to inactivate E. coli O157:H7 on diverse surfaces in food processing and handling environments.

Obesity is inversely related to the risks of dental caries in Korean adults.

OBJECTIVE: This study investigated whether obesity is linked with dental caries. This study hypothesized that obesity may influence the number or prevalence of dental caries in Korean adults. SUBJECTS AND METHODS: Data were derived from Korea National Health and Nutrition Examination Survey performed at 2008-2010. Lifestyle, sociodemographic, and biochemical variables were analyzed. Indices related to obesity, sarcopenia, and metabolic syndrome were investigated. Finally, caries index and oral health behaviors were included for the analysis. RESULTS: The caries index was inversely associated with increasing body mass index (BMI) and body fat quartile (all p-values <.01). Subjects with high waist circumference who met the inclusion criteria of metabolic syndrome were less likely to have decayed tooth (p-value = .0009). Subjects with a BMI of 25 or more showed about 20% less prevalence of dental caries experience than normal individuals with a BMI of 18.5 to 23 glucose (odds ratio [95% confidence intervals] = 0.808 [0.684-0.956]). Similarly, subjects with total body fat in the highest quartile revealed about 20% less prevalence of caries experiences that those with body fat proportion in the lowest quartile (0.84 [0.672,1.049]). CONCLUSIONS: Obesity was inversely associated with occurrence or severity of dental caries in Korean adults.

Type 2 diabetes as a risk indicator for dental caries in Korean adults: the 2011-2012 Korea national health and nutrition examination survey.

OBJECTIVES: The associations between type 2 diabetes (T2D) and untreated dental caries was examined. This study hypothesized that there would be a positive association between T2D and the prevalence of decayed permanent teeth (DT) in representative Korean adults. METHODS: The information was derived from the Korea National Health and Nutrition Examination Survey conducted in 2011-2012. Sociodemographic and lifestyle variables, anthropometric and biochemical status, metabolic health and glucose tolerance status, oral health behaviors, and dental caries index were evaluated. RESULTS: The number of DT had a positive association with degree of fasting plasma glucose (FPG) level, and glycated hemoglobin (HbA1c) (p-value = 0.045 and 0.007, respectively). The levels of FPG and HbA1c increased with the number of DT (p for trend = 0.009 and 0.004, respectively). The prevalence of untreated caries uncontrolled T2D participants was about 26% higher than those with normal glucose tolerance levels after adjusting for potential confounders including diets and socioeconomic status (OR [95% CI] = 1.26 [1.02, 1.56]). CONCLUSIONS: T2D is an independent risk indicator for untreated caries in Korean adults.

The association between periodontitis and obstructive sleep apnea: a preliminary study.

BACKGROUND AND OBJECTIVE: Periodontitis is becoming a highly prevalent disease worldwide. Obstructive sleep apnea (OSA) is a common disorder that is characterized by repeated disruptions in breathing during sleep, and mouth breathing is a common characteristic among patients with OSA. We aimed to assess the hypothesis that OSA is associated with the onset and progression of periodontal disease. MATERIAL AND METHODS: This is a cross-sectional study of a total of 687 participants (460 men and 227 women), 47-77 years of age, who were examined between August 2009 and September 2010 as part of the Korean Genome and Epidemiology Study. The participants underwent standard polysomnography, clinical periodontal examination and health-screening examinations. Periodontitis was defined as clinical attachment level (CAL) ≥ 6 mm and probing pocket depth ≥ 4 mm. OSA was determined using the apnea-hypopnea index (AHI), and an AHI score of ≥ 5 was the cut-off used to indicate the presence of OSA. RESULTS: The results showed that 17.5% of the participants had periodontitis, 46.6% had OSA and 60.0% who were diagnosed with periodontitis had OSA. In our study, old age, male gender, current smoking status, mouth breathing during sleep and high AHI were identified as risk factors for periodontitis. OSA was positively associated with periodontitis [odds ratio (OR) = 1.84, 95% confidence interval (CI) = 1.18-2.87], probing pocket depth (OR = 2.22, 95% CI = 1.30-3.77) and CAL (OR = 1.86, 95% CI = 1.07-3.21) in a dose-response manner. Additionally, OSA was positively associated with periodontitis (OR = 2.51, 95% CI = 1.37-4.62) in subjects ≥ 55 years of age, but not in subjects < 55 years of age. CONCLUSION: There is a significant association between OSA and periodontal disease. Further research is needed to clarify the causal relationship between the two conditions.

Association of total tooth loss with socio-behavioural health indicators in Korean elderly.

This study examined the association between total tooth loss, and socio-behavioural factors and general health indicators in elderly Koreans using national databases. Cross-sectional data for this study were from the third Korean National Health and Nutrition Examination Survey (KNHANES III), which was conducted among non-institutionalised civilians by the Korean Ministry of Health and Welfare in 2005. KNHANES III used a stratified, multistage probability sampling design on a representative of total South Korean population, according to geographical areas, age and sex groups. Among them, 1091 subjects aged 65 years and above were identified as potential participants in this study. The dependent variable in this study was the self-reported total tooth loss. The independent variables consisted of the following four categories: demographic information, socio-behavioural factors, psychological factors and general health indicators. The data were weighted to adjust for the sampling complexity, and SPSS version 14 for Windows software was used for data analysis. There were significant differences in total tooth loss odds according to the socio-behavioural backgrounds (education and smoking), psychological conditions (perceived oral health) and general health status (diabetes and body mass index as underweight). This suggests that the total tooth loss is associated with the socio-economic status, health-related behaviour and general health. However, more extensive longitudinal data and research will be needed to better explain the relationship between the total tooth loss and these variables.

Subjective food intake ability in relation to the Mixing Ability Index in Korean adults.

This study examined the association between the subjective food intake ability (FIA) using a questionnaire with 30 types of foods and the objective Mixing Ability Index (MAI) using a two-coloured wax cube. A total of 147 subjects (32 males, 115 females, mean age: 54.9 +/- 20.7) were enrolled in this study. The FIA for 30 food types and the key food intake ability (KFIA) for five key food types were obtained using a self-assessed questionnaire to evaluate the subjective chewing ability. The objective chewing ability was evaluated by asking the subjects to chew a wax cube for 10 strokes. The MAI was calculated by image analysis of the chewed wax cube. The Pearson's correlation between the subjective FIA and objective MAI was analysed according to age and number of post-canine teeth lost. The FIA for the 30 foods and five key food types showed a moderate correlation with the MAI (r = 0.51, 0.55, respectively, P < 0.01). The KFIA of the denture wearing group (r = 0.44, P < 0.01) and over 60-year-old group (r = 0.49, P < 0.01) showed a significantly higher correlation with the MAI than the other groups. In conclusion, there was a moderate correlation between the subjective FIA and objective MAI in Korean adults.

Automated Detection of TMJ Osteoarthritis Based on Artificial Intelligence.

The purpose of this study was to develop a diagnostic tool to automatically detect temporomandibular joint osteoarthritis (TMJOA) from cone beam computed tomography (CBCT) images with artificial intelligence. CBCT images of patients diagnosed with temporomandibular disorder were included for image preparation. Single-shot detection, an object detection model, was trained with 3,514 sagittal CBCT images of the temporomandibular joint that showed signs of osseous changes in the mandibular condyle. The region of interest (condylar head) was defined and classified into 2 categories-indeterminate for TMJOA and TMJOA-according to image analysis criteria for the diagnosis of temporomandibular disorder. The model was tested with 2 sets of 300 images in total. The average accuracy, precision, recall, and F1 score over the 2 test sets were 0.86, 0.85, 0.84, and 0.84, respectively. Automated detection of TMJOA from sagittal CBCT images is possible by using a deep neural networks model. It may be used to support clinicians with diagnosis and decision making for treatments of TMJOA.

Temporal Control of WNT Activity Regulates Tooth Number in Fish.

Wnts determine cell polarity, cell proliferation, and cell differentiation during embryogenesis and play an essential role during tooth development initiation and morphogenesis. Wnt/ß-catenin signaling has a time-dependent role in development because various signaling molecules that mutually interact are involved in the pathway, and tight regulation of the pathway is essential for normal development. Studies investigating how the Wnt/ß-catenin signaling pathway controls the different stages of tooth development are rare. Specifically, the effects of Wnt/ß-catenin signaling loss of function on different stages of tooth development are currently unknown. Here, we report the stage-dependent role of Wnt/ß-catenin signaling in tooth development. In vivo loss and gain of function of Wnt/ß-catenin signaling were implemented through the genetic overexpression of DKK1 with heat shock-inducible transgenic models and the pharmacologic inhibition of ß-catenin destruction complex formation in zebrafish, respectively. We demonstrated that transient inhibition of Wnt/ß-catenin signaling interrupted tooth development in a stage-dependent manner and conditional activation of Wnt/ß-catenin signaling during 4V morphogenesis inhibited the development of 3V. These findings suggest that Wnt/ß-catenin signaling plays an important role in the morphogenesis of teeth and the initiation of sequential tooth development in a stage-dependent manner.

Effect of Irradiance and Exposure Duration on Temperature and Degree of Conversion of Dual-Cure Resin Cement for Ceramic Restorations.

This study investigated the effects of irradiance and exposure duration on dual-cured resin cements irradiated through ceramic restorative materials. A single light-curing unit was calibrated to three different irradiances (500, 1000, and 1500 mW/cm2) and irradiated to three different attenuating materials (transparent acryl, lithium disilicate, zirconia) with 1-mm thicknesses for 20 or 60 seconds. The changes in irradiance and temperature were measured with a radiometer (or digital thermometer) under the attenuating materials. The degree of conversion (DC) of dual-cure resin cement after irradiation at different irradiances and exposure durations was measured with Fourier transform near infrared spectroscopy. Two-way analysis of variance revealed that irradiance ( p<0.001) and exposure duration ( p<0.001) significantly affected temperature and DC. All groups showed higher DCs with increased exposure times ( p<0.05), but there were no statistically significant differences between the groups irradiated with 1000 mW/cm2 and 1500 mW/cm2 ( p>0.05). Higher-intensity irradiances yielded higher temperatures ( p<0.05), but exposure time did not affect temperature when materials were irradiated at 500 mW/cm2 ( p>0.05).

NAMPT Is an Essential Regulator of RA-Mediated Periodontal Inflammation.

Recent studies have indicated a potential correlation between rheumatoid arthritis (RA) and periodontal inflammation. We undertook this study to verify whether RA mediates periodontitis-like phenotypes in experimental mouse models of RA and to explore the role of nicotinamide phosphoribosyltransferase (NAMPT) in periodontal inflammation during RA pathogenesis. Periodontal inflammation and alveolar bone loss have been reported in mice with collagen-induced arthritis (CIA) and in genetically modified tumor necrosis factor-α (TNF-α) transgenic (TG) mouse models. Among the adipokines examined in our study, NAMPT expression was markedly upregulated in the periodontal ligament (PDL) tissues in RA mouse models and in human PDL cells stimulated by the proinflammatory cytokines, interleukin (IL) 1ß and TNF-α. When NAMPT was overexpressed with the Nampt-synthesizing adenovirus vector (Ad- Nampt), the PDL cells exhibited an increased expression of cytokines (IL6), chemokines (IL8 and chemokine [C-C motif] ligand 5 [CCL5]), inflammatory mediators (cyclooxygenase 2 [COX-2]), and matrix-degrading enzymes (matrix metalloproteinase [MMP] 1 and MMP3). Inhibition of NAMPT by the intracellular NAMPT (iNAMPT) inhibitor, FK866, or by the sirtuin inhibitor, nicotinamide, in PDL cells led to inhibition of the IL1ß or Ad- Nampt-induced upregulation of catabolic factors, whereas treatment with recombinant NAMPT protein or blockade of extracellular NAMPT (eNAMPT) with blocking antibody did not. Moreover, NAMPT inhibition by the intraperitoneal or intragingival injection of FK866 in CIA mice inhibited periodontal tissue damage, under conditions of RA. Thus, our results verified the co-occurrence of RA and periodontal inflammation using experimental mouse models of RA, suggesting that iNAMPT in PDL cells plays a pivotal role in the pathogenesis of RA-mediated periodontal inflammation by regulating the expression levels of catabolic genes, such as IL6, IL8, CCL5, COX-2, MMP1, and MMP3.

Characterization and partial purification of liver glucose transporter GLUT2.

GLUT2, the major facilitative glucose transporter isoform expressed in hepatocytes, pancreatic beta-cells, and absorptive epithelial cells, is unique not only with its low affinity and broad substrate specificity as a glucose transporter, but also with its implied function as a glucose-sensor. As a first essential step toward structural and biochemical elucidation of these unique, GLUT2 functions, we describe here the differential solubilization and DEAE-column chromatography of rat hepatocyte GLUT2 protein and its reconstitution into liposomes. The reconstituted GLUT2 bound cytochalasin B in a saturable manner with an apparent dissociation constant (K(d)) of 2.3 x 10(-6) M and a total binding capacity (B(T)) of 8.1 nmol per mg protein. The binding was completely abolished by 2% mercury chloride, but not affected by cytochalasin E. Significantly, the binding was also not affected by 500 mM D-glucose or 3-O-methyl D-glucose (3OMG). The purified GLUT2 catalyzed mercury chloride-sensitive 3OMG uptake, and cytochalasin B inhibited this 3OMG uptake. The inhibition was dose-dependent with respect to cytochalasin B, but was independent of 3OMG concentrations. These findings demonstrate that our solubilized GLUT2 reconstituted in liposomes is at least 60% pure and functional, and that GLUT2 is indeed unique in that its cytochalasin B binding is not affected by its substrate (D-glucose) binding. Our partially purified GLUT2 reconstituted in vesicles will be useful in biochemical and structural elucidation of GLUT2 as a glucose transporter and as a possible glucose sensor.

Water-soluble lipopolymer as a gene carrier to corpus cavernosum.

Adenovirus or naked plasmid DNA (pDNA) has been used to deliver the therapeutic gene into corpus cavernosum. However, the potential risks of viral vector and inefficiency of naked pDNA have limited their clinical application. In this study, water-soluble lipopolymer (WSLP) was evaluated as a gene carrier to corpus cavernosum. The WSLP/pDNA complex was transfected to smooth muscle cells in vitro. WSLP had high transfection efficiency, which was comparable to poly(ethylenimine) (PEI). In addition, WSLP had much less cytotoxicity than PEI, suggesting that WSLP is a safer carrier than PEI. To evaluate the transfection efficiency to corpus cavernosum, the WSLP/pDNA complex was injected into the rat corpus cavernosum. As a result, the WSLP/pDNA complex showed higher transfection efficiency than naked pDNA. In addition, the gene expression was dependent upon the dose of the complex. The results suggest that WSLP may be useful for gene therapy of erectile dysfunction.

A pilot-scale photocatalyst-membrane hybrid reactor: performance and characterization.

We developed and tested a pilot-scale photocatalyst-membrane hybrid reactor for water treatment. The performance of the pilot-scale reactor was evaluated by monitoring the degradation efficiency of several organic pollutants and the membrane suction pressure at different operating conditions. The concentration of humic acids rather increased in the initial period of UV illumination and then decreased gradually, which could be ascribed to the photoinduced desorption of humic acids from the TiO2 surface. The decoloring rate of methylene blue was faster than that of rhodamine B, whereas the order of mineralization rates of the dyes was reversed. 4-chlorophenol of 100 ppb was fully degraded under UV irradiation in 2 hours, which suggests that this hybrid reactor would be more suitable in removing micropollutants in water. The reactor was operated with either continuous or intermittent suction mode. In a continuous suction mode, the formation of TiO2 cake layers on the membrane surface occurred and caused a substantial increase in suction pressure. However, no further fouling (or suction pressure build-up) took place with an intermittent suction mode with the 9-min suction and 3-min pause period. The photocatalyst-membrane hybrid reactor system developed in this study could be an attractive option for controlling micropollutants in water.

A randomised controlled trial of cemented and cementless femoral components for metal-on-metal hip resurfacing: a bone mineral density study.

The primary purpose of this study of metal-on-metal (MoM) hip resurfacing was to compare the effect of using a cementless or cemented femoral component on the subsequent bone mineral density (BMD) of the femoral neck. This was a single-centre, prospective, double-blinded control trial which randomised 120 patients (105 men and 15 women) with a mean age of 49.4 years (21 to 68) to receive either a cemented or cementless femoral component. Follow-up was to two years. Outcome measures included total and six-point region-of-interest BMD of the femoral neck, radiological measurements of acetabular inclination, neck-shaft and stem-shaft angles, and functional outcome scores including the Harris hip score, the Western Ontario and McMaster Universities Osteoarthritis Index and the University of California at Los Angeles activity scale. In total, 17 patients were lost to follow-up leaving 103 patients at two years. There were no revisions in the cementless group and three revisions (5%) in the cemented group (two because of hip pain and one for pseudotumour). The total BMD was significantly higher in the cementless group at six months (p < 0.001) and one year (p = 0.01) than in the cemented group, although there was a loss of statistical significance in the difference at two years (p = 0.155). All patient outcomes improved significantly: there were no significant differences between the two groups. The results show better preservation of femoral neck BMD with a cementless femoral component after two years of follow-up. Further investigation is needed to establish whether this translates into improved survivorship.

COUP-TFII Stimulates Dentin Sialophosphoprotein Expression and Mineralization in Odontoblasts.

Chicken ovalbumin upstream promoter transcription factor 2 (COUP-TFII), an orphan nuclear receptor belonging to the steroid-thyroid hormone receptor superfamily, plays an important role in cell fate determination of various tissues. However, the specific role of COUP-TFII in tooth development has not yet been elucidated. In the present study, we aimed to explore the role of COUP-TFII in dentin sialophosphoprotein (DSPP) expression and matrix mineralization in odontoblast-lineage cells. In primary human dental pulp cells (HDPCs) and murine dental papilla-derived cells (MDPC-23) cultured in a mineralizing medium, the expression of COUP-TFII was induced along with the increased odontoblast-specific dentin matrix protein-1 (DMP-1) and DSPP expression. Endogenous expression of COUP-TFII in maxillary second molar germs of rats showed an increasing tendency as development of the tooth progressed. Also, COUP-TFII protein was detected in greater quantity in the odontoblastic layer of second molar germs than in that of third molar germs of rats. Overexpression of COUP-TFII using an adenoviral system upregulated the expression of odontoblast-specific genes with increased alkaline phosphatase activity and matrix mineralization in odontoblast-lineage cells. In contrast, knockdown of COUP-TFII using small interfering RNA decreased the expression of odontoblast-specific genes, which reduced matrix mineralization. Mechanistic studies revealed that COUP-TFII increased DSPP transcription by direct binding on the DSPP promoter. In addition, COUP-TFII physically interacted with the homeodomain transcription factor Msx2 and antagonistically regulated the Msx2 effect on DSPP promoter activity. Taken together, these results suggest that COUP-TFII has a stimulatory role in DSPP expression and matrix mineralization in odontoblast-lineage cells.

Mandibular reconstruction using a titanium plate: the impact of radiation therapy on plate preservation.

PURPOSE: To evaluate the soft tissue and bone tolerance of radiation therapy (RT) in patients undergoing radical composite resection and mandibular reconstruction using a bridging titanium plate with myocutaneous flap closure. METHODS AND MATERIALS: From 1990 to 1994, 47 patients with primary or recurrent oral cavity or oropharyngeal carcinomas were treated with radical composite resection and mandibular reconstruction using a bridging titanium plate with myocutaneous flap closure. Eleven patients received no RT (no RT), 10 patients received RT greater than 10 months from the time of surgery (remote RT), and 26 patients received RT within 12 weeks of surgery (perioperative RT). The radiation dose to the reconstructed mandible ranged from 45 to 75 Gy (median 63 Gy). The effect of the titanium plate on the radiation dose was measured using film dosimetry and soft tissue and bone-equivalent materials. The median follow-up was 17 months (range: 3-50 months). RESULTS: Late complications included four patients with osteomyelitis or necrosis, two plate exposures requiring flap revision, one chronic infection, two cases of chronic pain, two fistulae, and one case of trismus and malocclusion. The crude incidence of late complications by treatment was: (a) no RT: 3 of 11 patients (27%); (b) remote RT: 2 of 10 patients (20%); and (c) perioperative RT: 9 of 26 patients (35%). One patient in the no-RT group lost the plate due to chronic pain. Five patients in the perioperative RT group also had plate loss, four due to osteomyelitis and/or necrosis, and one due to pain related to a recurrent tumor. No patients in the remote RT group had plate loss. The actuarial prosthesis preservation rate at 2 years was 88% for the no RT, 100% for the remote RT, and 57% for the perioperative RT groups (p = 0.05). Phantom dose measurements showed that for parallel opposed 6 MV photon beams, there was no significant increase in the dose proximal or distal to the plate in either a soft tissue- or bone-equivalent phantom. CONCLUSIONS: The impact of radiation therapy on plate preservation after mandibular reconstructive surgery using a titanium plate may be dependent on the timing of RT relative to surgery. Significantly more mandibular reconstruction plates were lost when the involved mandible received RT in the perioperative period than when RT was delivered beyond 10 months from surgery or when no RT was given. The use of alloplastic implants such as titanium plates in conjunction with myocutaneous flap coverage for mandibular reconstruction is attractive because it allows immediate reconstruction of the defect and promotes a good functional and cosmetic result; however, administration of perioperative RT may result in a higher plate failure rate.

Increased bioavailability of propranolol in rats by retaining thermally gelling liquid suppositories in the rectum.

Mucoadhesive liquid suppositories were prepared by adding mucoadhesive polymers (0.6%) to a formulation of thermally gelling suppositories that contained poloxamer 407 (15%), poloxamer 188 (15%) and propranolol HCl (2%). Hydroxypropylcellulose (HPC), polyvinylpyrrolidone (PVP), carbopol, polycarbophil and sodium alginate were examined as mucoadhesive polymers. The characteristics of the suppositories differed depending on the choice of mucoadhesive polymer. For example, the gelation temperature was between 30 and 36 degrees C, the mucoadhesive force was between 430 and 5800 dyne/cm2, the apparent first-order release rate constant in phosphate buffer, pH 6.8, was between 0.399 and 0.271 h-1, the migration distance of the suppository in the rectum 4 h after administration was between 1 and 5 cm, and the bioavailability of propranolol was between 60.9 and 84.7%. Rectal bioavailability increased as the mucoadhesive force increased (r=0.984, p<0.0005), and the migration distance decreased (r=-0.951, p<0.005). No relationship was found between the bioavailability and the gelation temperature, drug release or irritation of the rectal mucosal membrane by the suppository. Therefore, retaining propranolol at the dosed site in the rectum by the addition of appropriate mucoadhesives to the formulation of liquid suppositories appears to be a very important factor in avoiding first-pass hepatic elimination and thereby increasing the bioavailability of the drug. Among the mucoadhesive polymers examined, sodium alginate and polycarbophil exhibited the largest mucoadhesive force and the smallest intrarectal migration resulting in the largest bioavailability of propranolol (84.7 and 82.3%, respectively). In contrast to other polymers, sodium alginate alone caused no irritation of the rectal mucosal membrane. Thus, poloxamer liquid suppositories containing sodium alginate appears to be a preferred formulation for drugs that are sensitive to extensive first-pass metabolism.

Clonazepam release from core-shell type nanoparticles of poly(epsilon-caprolactone)/poly(ethylene glycol)/poly(epsilon-caprolactone) triblock copolymers.

The triblock copolymer based on poly(epsilon-caprolactone) (PCL) as hydrophobic part and poly(ethylene glycol) (PEG) as hydrophilic one was synthesized and characterized. Core-shell type nanoparticles of poly(epsilon-caprolactone)/poly(ethylene glycol)/poly(epsilon-caprolactone) (CEC) block copolymer were prepared by a dialysis technique. According to the amphiphilic characters, CEC block copolymer can self-associate at certain concentration and their critical association concentration (CAC) was determined by fluorescence probe technique. CAC value of the CEC-2 block copolymer was evaluated as 0.0030 g/l. CAC values of CEC block copolymer decreased with the increase of PCL chain length, i.e. the shorter the PCL chain length, the higher the CAC values. From the observation of transmission electron microscopy (TEM), the morphologies of CEC-2 core-shell type nanoparticles were spherical shapes. Particle size of CEC-2 nanoparticles was 32.3+/-17.3 nm as a monomodal and narrow distribution. Particle size, drug loading, and drug release rate of CEC-2 nanoparticles were changed by the initial solvents and the molecular weight of CEC. The degradation behavior of CEC-2 nanoparticles was observed by 1H NMR spectroscopy. It was suggested that clonazepam (CNZ) release kinetics were dominantly governed by diffusion mechanism.

The evaluation of working casts prepared from digital impressions.

OBJECTIVE: The aim of this study is to evaluate the reproducibility of working casts of a digital impression system by comparing them with the original, virtual, and rapid prototyping casts. MATERIALS AND METHODS: A total of 54 cast sets in clinically stable occlusion were used. They were scanned by an iTero intraoral scanner and converted into STL format virtual casts. Rapid prototyping casts and polyurethane casts were fabricated from the iTero milling system based on the virtual casts. Several horizontal and vertical measurements were performed from the four types of casts, that is, original stone casts, virtual casts, rapid prototyping casts, and polyurethane casts of iTero. Measurement error, intraclass correlation coefficient (ICC), and differences among the casts were calculated and compared. RESULTS: Casts from iTero milling machines exhibited greater dimensional differences and lower ICC values than did other casts. In addition, many of the measurements of the iTero working casts showed statistically significant differences in comparison to the three other types of casts. In contrast, there were no statistically significant differences between the virtual and original casts. CONCLUSION: Virtual casts made by the iTero intraoral scanner exhibited excellent reproducibility. However, the casts from the iTero milling machine showed greater dimensional differences and lower reproducibility compared to other types of casts.

A guanidinylated bioreducible polymer as a novel gene carrier to the corpus cavernosum of mice with high-cholesterol diet-induced erectile dysfunction.

A prerequisite for the successful clinical application of gene therapy in erectile dysfunction (ED) is the availability of safe and efficient gene delivery systems. The aim of this study was to examine the effectiveness of guanidinylated bioreducible polymer (GBP) polyplexes for gene delivery systems, which take advantage of the biodegradability of reducible disulfide bonds and the cell-penetrating ability of guanidine groups. For in vitro transfection experiments, we used mouse cavernous endothelial cells and A7r5 rat vascular smooth muscle cells. For in vivo experiments, we used a mouse model of hypercholesterolaemic ED in which 2-month-old male C57BL/6 mice were fed a diet containing 4% cholesterol and 1% cholic acid for 3 months. Animals or cells were treated with pCMV-Luc, poly(ethyleneimine) (PEI)25k/pCMV-Luc polyplex (weight ratio: 1) and GBP/pCMV-Luc polyplexes (weight ratio: 20, 40, 60 and 80). Gene expression was evaluated by luciferase assay, and the gene expression area was evaluated by immunohistochemistry. GBP had greater transfection efficiency as the weight ratio increased. GBP had sevenfold higher gene delivery efficiency in A7r5 cells at a weight ratio of 80 than did PEI25k. Moreover, the gene expression was more profoundly induced by GBP/pCMV-Luc than by pCMV-Luc in both the corpus cavernosum tissue of hypercholesterolaemic mice and in mouse cavernous endothelial cells, although the expression levels induced by the GBP gene delivery system were lower than those induced by the PEI25k gene delivery system. GBP revealed no considerable cytotoxicity to A7r5 cells and mouse cavernous endothelial cells (relative cell viability: 95 and 88% respectively), whereas PEI25k resulted in high cytotoxicity. Interestingly, immunofluorescent double staining revealed that luciferase expression induced by the GBP polyplex mainly overlapped with cavernous endothelial cells, but rarely with smooth muscle cells. The GBP-based non-viral gene expression system may be useful for the development of gene therapy in vasculogenic ED.