Quantitative analysis of maxillary palatal masticatory mucosa thickness and anatomical morphology of palatal vault in Zhejiang province.

OBJECTIVE: To quantitatively analyze the maxillary palatal masticatory mucosa thickness and anatomical morphology of palatal vault in Zhejiang province. METHODS: Cone beam computed tomography (CBCT) images of 146 adult patients were collected from outpatients in Department of Stomatology, the First Affiliated Hospital, Zhejiang University School of Medicine. The images were reconstructed by adjusting the reference line and analyzed on the sagittal plane of the measured teeth. The thickness of masticatory mucosa from maxillary canine to second molar area was measured at the level of 3, 6, 9, 12 mm from the gingival margin. At the same time, the height and width of the palatal vault were measured, the position of the greater palatal foramen relative to the second molar, and the distance from the greater palatal foramen to the mid-palatal suture and the alveolar crest were determined. Spearman correlation analysis and multiple regression analysis were used to explore the influencing factors of the maxillary masticatory mucosa thickness. One-way analysis of variance and LSD multiple comparisons were used to analyze the difference in palatal mucosal thickness of each tooth position in different age groups. The sample t-test was used to analyze the differences in the mucosal thickness of each tooth position and the distance from the greater palatal foramen to the mid-palatal suture and the alveolar crest in different anatomical forms of the palatal vault. RESULTS: The mean palatal masticatory mucosa thickness from maxillary canines, first premolars, second premolars, first molar and second molar areas were (2.94±0.48), (3.28±0.49), (3.43±0.53), (3.01±0.55), (3.49±0.70) mm, respectively. The mucosa thickness of canines, first premolars and second premolars areas showed increasing at first and then decreasing trend. The mucosal thickness of the canines area was greatest at 6 mm from the gingival margin, and the thickness of the first and second premolars areas was greatest at 9 mm from the gingival margin. Premolars are thickest at 9 mm from the gingival margin. The thickness of the mucosa of the first molars area increased with the increase of the distance from the gingival margin, and the thickness of the mucosa of the second molars area was the thinnest at 6 mm, and then increased with the increase of the distance from the gingival margin. The main influencing factors of the mucosal thickness of canines, first premolars and first molars areas were age and palatal vault aspect ratio, the main influencing factor of the mucosal thickness of second premolars area was age, and the main influencing factor of the mucosal thickness of second molars area was palatal vault aspect ratio. There was no significant colinearity among the variables ( VIF<10). The results of the further stratified analysis showed that the mucosal thickness of the maxillary canine to the first molar area was positively correlated with age, and mucosal thickening is more pronounced in people aged 45 years old and above. The thickness of the canine mucosa in the high palate vault group was greater than that in the low palate vault group ( P<0.05), and the thickness of the second molar mucosa was smaller than that in the low palate vault group ( P<0.05). The greater palatal foramen was mostly located in the distal region of the second molar crown. The distance from the greater palatal foramen to the alveolar crest in the high palatal vault group was greater than that in the low palatal vault group ( P<0.05), while there was no significant difference between the two groups in the distance from the foramen magnum to the mid-palatal suture ( P>0.05). CONCLUSION: The most suitable donor site for autologous soft tissue graft may be 3-9 mm from the gingival margin of the first and second premolars area.

Enhanced Oral Absorption of Icaritin by Using Mixed Polymeric Micelles Prepared with a Creative Acid-Base Shift Method.

The purpose of this study was to develop mixed polymeric micelles with high drug loading capacity to improve the oral bioavailability of icaritin with Soluplus® and Poloxamer 407 using a creative acid-base shift (ABS) method, which exhibits the advantages of exclusion of organic solvents, high drug loading and ease of scaling-up. The feasibility of the ABS method was successfully demonstrated by studies of icaritin-loaded polymeric micelles (IPMs). The prepared IPMs were characterized to have a spherical shape with a size of 72.74 ± 0.51 nm, and 13.18% drug loading content. In vitro release tests confirmed the faster release of icaritin from IPMs compared to an oil suspension. Furthermore, bioavailability of icaritin in IPMs in beagle dogs displayed a 14.9-fold increase when compared with the oil suspension. Transcellular transport studies of IPMs across Caco-2 cell monolayers confirmed that the IPMs were endocytosed in their intact forms through macropinocytosis, clathrin-, and caveolae-mediated pathways. In conclusion, the results suggested that the mixed micelles of Soluplus® and Poloxamer 407 could be a feasible drug delivery system to enhance oral bioavailability of icaritin, and the ABS method might be a promising technology for the preparation of polymeric micelles to encapsulate poorly water-soluble weakly acidic and alkaline drugs.

Preparation, Characterization, and In Vivo Evaluation of Amorphous Icaritin Nanoparticles Prepared by a Reactive Precipitation Technique.

Icaritin is a promising anti-hepatoma drug that is currently being tested in a phase-III clinical trial. A novel combination of amorphization and nanonization was used to enhance the oral bioavailability of icaritin. Amorphous icaritin nanoparticles (AINs) were prepared by a reactive precipitation technique (RPT). Fourier transform infrared spectrometry was used to investigate the mechanism underlying the formation of amorphous nanoparticles. AINs were characterized via scanning electron microscopy, X-ray powder diffraction, and differential scanning calorimetry. Our prepared AINs were also evaluated for their dissolution rates in vitro and oral bioavailability. The resultant nanosized AINs (64 nm) were amorphous and exhibited a higher dissolution rate than that derived from a previous oil-suspension formulation. Fourier transform infrared spectroscopy (FTIR) revealed that the C=O groups from the hydrophilic chain of polymers and the OH groups from icaritin formed hydrogen bonds that inhibited AIN crystallization and aggregation. Furthermore, an oral administration assay in beagle dogs showed that Cmax and AUClast of the dried AINs formulation were 3.3-fold and 4.5-fold higher than those of the oil-suspension preparation (p < 0.01), respectively. Our results demonstrate that the preparation of amorphous drug nanoparticles via our RPT may be a promising technique for improving the oral bioavailability of poorly water-soluble drugs.

Expression of endoplasmic reticulum stress protein in rabbit condyle cartilage following anterior disk displacement.

OBJECTIVE: Anterior disk displacement (ADD) is a most common subtype of temporomandibular disorders (TMD), which is promoted by chondrocytes apoptosis. However, the signaling pathways that trigger apoptosis are still unknown. The aim of this study was to investigate the expression of endoplasmic reticulum (ER) stress-related proteins in the condylar cartilage of rabbits following ADD. METHODS: Sixty healthy adult rabbits were randomly assigned to the experimental and sham-operated control groups (n = 12). The experimental rabbits were subjected to surgical ADD in the right temporomandibular joints. The production of ER stress-related proteins C/EBP homologous protein (CHOP), glucose-regulated protein 78 (GRP78), cleaved caspase-3, and caspase-12 in cartilage was evaluated by immunohistochemistry, quantitative real-time PCR, and Western blot analysis. RESULTS: Our results showed that the expression of CHOP, GRP78, cleaved caspase-3, and caspase-12 increased significantly along with degenerative changes in cartilage after ADD. CONCLUSION: These results indicate that the ER stress pathway is activated in ADD cartilage and might promote the development of TMD.

Health-care access among adults with epilepsy: The U.S. National Health Interview Survey, 2010 and 2013.

INTRODUCTION: Community-based and other epidemiologic studies within the United States have identified substantial disparities in health care among adults with epilepsy. However, few data analyses addressing their health-care access are representative of the entire United States. This study aimed to examine national survey data about adults with epilepsy and to identify barriers to their health care. MATERIALS AND METHODS: We analyzed data from U.S. adults in the 2010 and the 2013 National Health Interview Surveys, multistage probability samples with supplemental questions on epilepsy. We defined active epilepsy as a history of physician-diagnosed epilepsy either currently under treatment or accompanied by seizures during the preceding year. We employed SAS-callable SUDAAN software to obtain weighted estimates of population proportions and rate ratios (RRs) adjusted for sex, age, and race/ethnicity. RESULTS: Compared to adults reporting no history of epilepsy, adults reporting active epilepsy were significantly more likely to be insured under Medicaid (RR=3.58) and less likely to have private health insurance (RR=0.58). Adults with active epilepsy were also less likely to be employed (RR=0.53) and much more likely to report being disabled (RR=6.14). They experience greater barriers to health-care access including an inability to afford medication (RR=2.40), mental health care (RR=3.23), eyeglasses (RR=2.36), or dental care (RR=1.98) and are more likely to report transportation as a barrier to health care (RR=5.28). CONCLUSIONS: These reported substantial disparities in, and barriers to, access to health care for adults with active epilepsy are amenable to intervention.

Bilayer metallic nanofilms as broadband antireflection coatings in terahertz optical systems.

We present the potential of ultrathin bilayer metallic nanofilms for use as broadband antireflection coatings in the terahertz frequency range. The metallic layers are modeled using a wave-impedance matching approach. The experimental and theoretical results are in good agreement. Further, a novel method using our broadband antireflection coatings is proposed to eliminate unwanted reflections that interfere with the important reflection from the sample in terahertz reflection measurement. The proposed method significantly improves the calculation of the optical properties of liquid and biological samples.

A randomized double-blind placebo-controlled study of the efficacy of Clinpro XT varnish and Gluma dentin desensitizer on dentin hypersensitivity.

PURPOSE: To evaluate the effect of Clinpro XT Varnish (VXT) paste-liquid, resin-modified glass-ionomer and the resinous dentin desensitizing varnish and Gluma Dentin Desensitizer (Gluma) in treating dentin hypersensitivity (DH). METHODS: This short-term (4-week) randomized, double-blind, placebo-controlled, split-mouth study included a total of 119 teeth from 31 individuals which were randomized into three groups: VXT, Gluma, and placebo (warm water). Dentin sensitivity was evaluated by subjects' perception of DH determined by pretreatment tooth sensitivity score (TSS) measured on a 0-10 visual analogue scale (VAS) after tactile (probe) or thermal/evaporative (blast of air) stimuli. TSS was scored at baseline, immediately after treatment (Day 0), after 1 week and after 4 weeks. RESULTS: For both stimuli, mean TSS was significantly decreased in the VXT and Gluma groups at all time points (all, P < 0.001) compared with baseline. Regarding comparisons of TSS between treatment groups, the VXT group had significantly lower mean TSS compared with the Gluma group (P< 0.05) and placebo control group (P< 0.05) at all time points after treatment regardless of stimuli. Group Effect, Time Effect, and Group x Time Effect were all significantly different (all, P < 0.001).

Computational fluid dynamics in root canal irrigation.

Root canal irrigation is an important step in root canal preparation procedures and has a great impact on the success rate of root canal treatment. Computational fluid dynamics (CFD) is a new method to study root canal irrigation. It can be used to simulate and visualize the process of root canal irrigation, and quantitatively evaluate the effect of root canal irrigation through parameters such as flow velocity and wall shear stress. In recent years, researchers have conducted extensive studies on the factors that influence root canal irrigation efficiency, such as the position of the irrigation needle, the size of root canal preparation, the types of irrigation needles, and so on. This article reviewed the development of root canal irrigation research methods, the steps of CFD simulation in root canal irrigation, and the application of CFD in root canal irrigation in recent years. It aimed to provide new research ideas for the application of CFD to root canal irrigation and to provide a reference for the clinical application of CFD simulation results.

Visualized analysis of hotspots and frontiers in diabetes-associated periodontal disease research: a bibliometric study.

Background: Diabetes-associated periodontal disease is caused by diabetes-enhanced host immune-inflammatory responses to bacterial insult. An increasing number of papers related to diabetes-associated periodontal disease have been published. This study analyzed research on diabetes-associated periodontal disease with bibliometrics methods. The objective of this study was to identify hotspots and frontiers in the diabetes-associated periodontal disease research field. Methods: Publications were extracted from the Web of Science core collection database, and the document types included were limited to articles and reviews. The bibliometric analysis software CiteSpace5 was used to analyze the number of articles, research fields, countries/regions, institutions, authors, keywords, and other information. Outcomes were visualized to analyze the hotspots and research frontiers of diabetes-associated periodontal disease. Results: A total of 3,572 articles were retrieved. Among the research fields, dentistry, oral surgery, and medicine accounted for the highest proportion of publications, and public, environmental, and occupational health had the highest betweenness centrality. The number of publications from the United States ranked first among all the countries, while Columbia University ranked first among all the institutions. Global cooperation was not frequent. Keyword analysis showed that inflammatory pathways were the hotspots. Burst words analysis indicated that early prevention was a research frontier. Conclusions: The bibliometric method helped identify research hotspots and frontiers. Inflammatory pathways were hotspots, and early prevention was a frontier in diabetes-associated periodontal disease.

[The effect of four immunosuppressive drugs on oral manifestations after organ transplantation].

PURPOSE: To assess the prevalence of oral manifestations in a group of allogenic liver, kidney or haematopoietic stem cell transplantation recipients and patients, and analyze the possible oral manifestations associated with the use of 4 immunosuppressive drugs. METHODS: One hundred and eighteen patients submitted to liver, kidney and hematopoietic stem cell transplantation who used tacrolimus， sirolimus，cyclosporine or mycophenolate mofetil were enrolled. Through a questionnaire survey and oral examination, their oral manifestations were recorded, and the possible statistical associations with immunosuppressive drugs were analyzed using SPSS 21.0 software package. RESULTS: The prevalence of oral lichenoid lesions and cheilitis for the group of patients using tacrolimus after transplantation was significantly lower than the group of patients who did not used the agent(P＜0.01). The prevalence of oral lichenoid lesions for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P＜0.05), and the prevalence of cheilitis for the group of patients who used cyclosporine was significantly higher than the group of patients who did not used the drug(P＜0.01). The prevalence of oral lichenoid lesions and cheilitis for the group of patients who used tacrolimus was significantly lower than the group of patients who used cyclosporine(P＜0.01). The group of patients who used mycophenolate mofetil after transplantation had a significantly lower prevalence of dry mouth than the group of patients who did not used the drug(P＜0.01). The prevalence of oral manifestations in patients with sirolimus after transplantation was not significantly reduced. CONCLUSIONS: The use of tacrolimus improved the symptoms of oral lichenoid lesions and cheilitis and the effect was better than cyclosporine after transplantation. The use of mycophenolate mofetil improved dry mouth after organ transplantation.

Co-modification with MSC membrane and PDA prevents Fe3O4-induced pulmonary toxicity in mice via AMPK-ULK1 axis.

Fe3O4 nanoparticles are widely used in the diagnosis and treatment of diseases due to their superparamagnetism, but their toxicity in vivo, which can result in apoptosis or autophagy, cannot be ignored. It has been reported that polydopamine (PDA) modification can reduce the toxicity of Fe3O4 and increase its biocompatibility. However, more research is warranted to further improve the modification method. We therefore developed a new method to coat Fe3O4@PDA nanoparticles with the mesenchymal stem cell membrane (MSCM) and evaluated the toxicity of the modified particles in the lungs of mice. We found that the MSCM modification significantly reduced lung injury induced by Fe3O4 particles in mice. Compared with Fe3O4@PDA nanoparticles, co-modification with MSCM and PDA significantly reduced autophagy and apoptosis in mouse lung tissue, and reduced activation of autophagy mediated by the AMPK-ULK1 pathway axis. Thus, co-modification with MSCM and PDA prevents Fe3O4-induced pulmonary toxicity in mice by inhibiting autophagy, apoptosis, and oxidative stress.

Investigation of an Improved Side-Vented Needle and Corresponding Irrigation Strategy for Root Canal Therapy with CFD Method.

BACKGROUND AND OBJECTIVE: This research aimed to present an improved side-vented needle and explore its availability as well as the corresponding irrigation strategy. METHODS: A CFD model was used to simulate the irrigant flow in a simplified prepared round root canal with an apical delta respectively with different needles for irrigation. The needle types include flat end-tip needle, original side-vented needle, and improved side-vented needle. Different insertion depths and inlet velocities were contrastively studied, as well as the gap size between the bulb at the end tip of the improved side-vented needle and the root canal. The study includes a total of 13 schemes. Velocity, pressure, and shear stress in the root canal were measured to contrast the internal flow-field details and irrigation efficiencies between different schemes. RESULTS: Poor irrigation replacement appeared in the schemes without enough needle insertion no matter which kind of needle has been used, though relatively lower pressure emerged at the apical foramen. On the contrary, deepening needle insertion not only brings better irrigant replacement but also higher apical foramen pressure. The original side-vented needle tends to make lower pressure at the apical foramen and simultaneously worse irrigant replacement as compared to the flat end-tip needle. The fluid entering the apical anatomy part deceases a lot as the original side-vented needle was replaced by the improved one. The scheme using the improved side-vented needle with gap size ratio and inlet velocity respectively equaling 5.0% and 5.50m/s can be considered the best one. CONCLUSIONS: The improved side-vented needle can ensure acceptable irrigant replacement performance without leading to a high-pressure level at the apical foramen. The gap between the bulb and the wall of the root canal is very crucial for the pressure at the apical. The ideal irrigation strategy is ensuring the gap equals zero. However, it is a little hard to realize during the whole procedure of the root canal preparation except the final step. Consequently, another strategy that keeping the value of gap size ratio as small as possible such as less than 15% and simultaneously ensuring lower-velocity coming fluid, is necessary in the non-final irrigation.

Deep Red Emissive Carbonized Polymer Dots with Unprecedented Narrow Full Width at Half Maximum.

Development of high-performance carbon dots (CDs) with emission wavelength longer than 660 nm (deep red emission) is critical in deep-tissue bioimaging, yet it is still a major challenge to obtain CDs with both narrow full width at half maximum (FWHM) and high deep red/near-infrared emission yield. Here, deep red emissive carbonized polymer dots (CPDs) with unprecedented FWHM of 20 nm are synthesized. The purified CPDs in dimethyl sulfoxide (DMSO) solution possess quantum yield (QY) as high as 59% under 413 nm excitation, as well as recorded QY of 31% under 660 nm excitation in the deep red fluorescent window. Detailed characterizations identify that CPDs have unique polymer characteristics, consisting of carbon cores and the shells of polymer chains, and π conjugated system formed with N heterocycles and aromatic rings governs the single photoluminescence (PL) center, which is responsible for high QY in deep red emissive CPDs with narrow FWHM. The CPDs exhibit strong absorption and emission in the deep red light region, low toxicity, and good biocompatibility, making them an efficient probe for both one-photon and two-photon bioimaging. CPDs are rapidly excreted via the kidney system and hepatobiliary system.

Efficacy of Fe3O4@polydopamine nanoparticle-labeled human umbilical cord Wharton's jelly-derived mesenchymal stem cells in the treatment of streptozotocin-induced diabetes in rats.

Diabetes mellitus (DM) is characterized by the irreversible destruction of insulin-secreting pancreatic ß-islet cells and requires life-long exogenous insulin therapy. Umbilical cord Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) have been shown to improve islet function in animal models of diabetes. However, inadequate MSC homing to injured sites has limited their efficacy. Since efficient cell therapy heavily relies on appropriate homing to target tissues, increasing the specificity to the target organ and the extent of homing of the injected WJ-MSCs is paramount to successful clinical outcomes. Therefore, in this study, we synthesized Fe3O4@polydopamine nanoparticle (NP)-labeled MSCs and evaluated their therapeutic efficacy in a clinically relevant rat model of streptozotocin-induced diabetes using an external magnetic field. We found that NPs were successfully incorporated into WJ-MSCs and did not negatively affect stem cell properties. Magnetic targeting of WJ-MSCs contributed to long-term cell retention in pancreatic tissue and improved the islet function of diabetic rats, compared to injection of WJ-MSC alone. In addition, anti-inflammatory effects and the anti-apoptotic capacity of WJ-MSCs appeared to play a major role in the functional and structural recovery of the pancreas. Thus, therapy relying on the magnetic targeting of WJ-MSCs may serve as an effective approach for DM treatment.

Sandwich magnetically imprinted immunosensor for electrochemiluminescence ultrasensing diethylstilbestrol based on enhanced luminescence of Ru@SiO2 by CdTe@ZnS quantum dots.

A molecularly imprinted magnetic sensor with electroluminescent tags (MIP-ECL sensor) was developed for ultrasensing diethylstilbestrol (DES). A strategy is exploited to enhance ECL emission of the [Ru(bpy)3]2 +-tripropyl amine (TPrA) system by CdTe@ZnS quantum-dots (QDs) through energy transfer. Magnetically molecularly imprinted nanoparticles (MMIPs NPs) based on Fe3O4@SiO2 carriers are artificial, easily reproducible, and could replace easily inactivated first antibodies for capturing more DES molecules. Functionalized bio-conjugates of single antibody-CdTe@ZnS (Ab-CdTe@ZnS) are for the first time loaded on signal labels of Ru(bpy)32 +-doped silica nanocomposites (Ru@SiO2) for signal amplification. The final bio-conjugated signal probes are denoted as Ab-DES/CdTe@ZnS-Ru@SiO2. MMIPs beads that have captured antigens are bio-conjugated with antibody-labeled luminescent probes by specific immunoreactive reaction, and then the luminescent immunocomplex generates ECL signal on the magnetic electrode. The logarithm of ECL intensities depend linearly on the logarithm of DES concentrations in the range from 4.8 × 10- 4 to 36.0 nM with a detection limit of 0.025 pM. This novel assay is much more sensitive than other MIP sensors, and achieves lower cost and more enhanced stability than other immunosensors. The sensor is significantly potential and has been applied to DES detection in actual environment.

[Effects of pit and fissure sealant combined with fluorine protective paint on prevention of children caries aged 5-8 years old].

PURPOSE: To investigate the effect of pit and fissure sealant combined with fluorine protective paint on prevention of children caries aged 5-8 years old. METHODS: Convenience sampling method was used to select 120 children who received oral health care in the First Affiliated Hospital of Zhejiang University and Hangzhou Dental Hospital from January 2014 to January 2017. They were grouped by random number table method: the control group (60 cases, 109 teeth) underwent pit and fissure sealant, and the experimental group (60 cases, 112 teeth) underwent pit and fissure sealant combined with fluorine protective paint. The patients were followed up for 2 years to compare the incident of dental caries. SPSS20.0 software package was used to analyze the data. RESULTS: The incidence of dental caries in the experiment group (2.68%) was significantly lower than that in the control group (10.09%) (P<0.05).The incidence of adjacent caries in the experiment group (1.79%) was significantly lower than that in the control group (9.17%) (P<0.05). At 1 and 2 years after sealing, the shedding rate(0.00%, 3.33%) of the sealant in the experiment group was significantly lower than that in the control group (10.00%, 15.00%)(P<0.05).The mean caries of the experiment group was significantly lower than that of the control group(P<0.05). CONCLUSIONS: The effect of combined pit and fissure sealant and fluoride protective paint on the prevention of dental caries in children aged 5-8 years old is ideal, which can reduce the incidence of dental caries and adjacent caries, reduce the mean caries, and keep the sealant intact. It is worthy of clinical promotion.

Role and mechanism of the nod-like receptor family pyrin domain-containing 3 inflammasome in oral disease.

OBJECTIVE: To summarize evidence and data from experimental studies regarding the role and mechanism of the Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in the pathogenesis of several representative oral diseases. MATERIALS AND METHODS: A literature search of PubMed and EBSCO was performed. The literature was searched using a combination of keywords, e.g., NLRP3 inflammasome, inflammation, microorganisms, oral inflammatory diseases, and oral immunological diseases. RESULTS: The initiation and activation of the NLRP3 inflammasome are associated with the pathogenesis and progression of several representative oral diseases, including periodontitis, oral lichen planus, dental pulp disease, and oral cavity squamous cell carcinoma. CONCLUSIONS: The NLRP3 inflammasome plays a crucial role in the progression of inflammatory and adaptive immune responses. The possible role of the NLRP3 inflammasome in several oral diseases, including not only periodontitis and pulpitis but also mucosal diseases and oral cavity squamous cell carcinoma, may involve the aberrant regulation of inflammatory and immune responses. Understanding the cellular and molecular biology of the NLRP3 inflammasome is necessary because the NLRP3 inflammasome may be a potential therapeutic target for the treatment and prevention of oral inflammatory and immunological diseases.

Size effect of nano-hydroxyapatite on proliferation of odontoblast-like MDPC-23 cells.

Nano-hydroxyapatite (nano-HAP) is supposed to be a promising candidate for apatite substitute in hard tissue engineering. We aimed to investigate the effect of nano-HAP particles on the proliferation of odontoblast-like MDPC-23 cells compared with conventional hydroxyapatite (c-HAP). HAP in diameter of ~20 nm (np20), ~70 nm (np70) and ~200 nm (c-HAP) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Inverted microscope and MTT assay were used to detect the morphology and proliferation rate of MDPC-23 cells; TEM was used to reveal the internalization of HAP. We found that nano-HAP (np20 and np70), especially np20 expressed obvious growth-promoting effect on MDPC-23 cells compared with c-HAP, which caused the most vacuole in MDPC-23 cells. These results suggest that nano-HAP may be an optimal choice of apatite substitute for MDPC-23 cells on the aspect of cell proliferation.

Impacts of leachates from single-use polyethylene plastic bags on the early development of clam Meretrix meretrix (Bivalvia: Veneridae).

Plastic debris in the oceans is a major and growing problem in global environmental pollution. There are increasing concerns that plastic debris is a source of contaminant, either added during manufacturing or adsorbed from the environment. However, there is little information about the acute toxicity of leachates from plastic debris on marine organisms. In this study, we conducted experiments to evaluate the toxicity of leachates from two single-use polyethylene plastic bags (PB1 and PB2) with the embryo and larvae of the commercial clam Meretrix meretrix. Results showed that fertilization of the embryos was not affected by plastic leachates, but the developments of D-veliger larvae, including survival, deformity, and shell height, were significantly affected by plastic leachates from both PB1 and PB2 compared to the controls of filtered seawater. We speculate that compounds leaching from plastic bags are responsible for the observed toxicity. Therefore, leaching toxicity from plastic debris should be considered when assessing the risks of plastic pollution in the oceans.