Rapid silica atomic layer deposition on large quantities of cohesive nanoparticles

Conformal silica films were deposited on anatase titania nanoparticles using rapid silica atomic layer deposition (ALD) in a fluidized bed reactor. Alternating doses of tris(tert-pentoxy)silanol (TPS) and trimethylaluminum (TMA) precursor vapors were used at 175 degrees C. In situ mass spectroscopy verified the growth mechanism through a siloxane polymerization process. Transmission electron microscopy revealed highly conformal and uniform silica nanofilms on the surface of titania nanoparticles. A growth rate of approximately 1.8 nm/cycle was achieved for an underdosed and incomplete polymerization reaction. Primary nanoparticles were coated despite their strong tendency to form dynamic agglomerates during fluidization. Methylene blue oxidation tests indicated that the photoactivity of anatase titania particles was mitigated with the ALD films.

Expression of c-kit and Slug correlates with invasion and metastasis of salivary adenoid cystic carcinoma

The overexpression of c-kit seems to be frequent and specific in salivary adenoid cystic carcinoma (ACC), however, there is little information on correlation between c-kit expression and the invasion and metastasis. Recently, the data showed that Slug, a transcription factor of epithelial-mesenchymal transitions (EMT), is a molecular target that contributes to the biological specificity of c-kit signaling pathway. In this study, the expression of c-kit and Slug was evaluated in two ACC cell lines and 121 patients with ACC. The results of real-time RT-PCR and Western blot showed that ACC-2 and ACC-M cell lines expressed c-kit and Slug mRNA and protein. The immunohistochemical assay in patients demonstrated that positive expression of c-kit and Slug was observed in 108/121 (89.26%) and 87/121 (71.90%) of cases, respectively, and that c-kit and Slug expression was significantly associated with tumor site, TNM stage, histological pattern, perineural invasion, local regional recurrence and distant metastasis of patients with ACC (P<0.05). Furthermore, there was a significant association between the positive expression of c-kit and that of Slug (P=0.046). These findings indicated that c-kit/Slug pathway might participate in the invasion and metastasis of salivary ACC.

Effects of intra-articular administration of sodium hyaluronate on plasminogen activator system in temporomandibular joints with osteoarthritis

OBJECTIVE

The aim of this study was to investigate the effect of intra-articular sodium hyaluronate (SH) injections on the main components of plasminogen activator (PA) system in the synovial fluid of temporomandibular joint (TMJ) osteoarthritis (OA).

STUDY DESIGN

Forty patients diagnosed with TMJ OA and 20 healthy control subjects were included in this study. Synovial fluid was collected in the OA group and the healthy group at baseline. The OA patients were randomly divided into 2 groups (20 patients for each group): One group received 5 injections of SH, and the other received 5 injections of physiologic saline solution in the upper joint space at weekly intervals. Synovial fluid was collected before and after treatment. Urokinase-type PA (uPA), soluble uPA receptor (suPAR) and PA inhibitor 1 (PAI-1) levels in synovial fluid were quantified by enzyme-linked immunosorbent assay.

RESULTS

The OA patients had significantly higher uPA activity and levels of uPA (median 80.01 ng/L), suPAR (median 7.54 ng/L), and PAI-1 (median 54.9 ng/mL) than the healthy control subjects (median 20.47 ng/L uPA, 2.34 ng/L suPAR, and 19.9 ng/mL PAI-1; (P < .05). The uPA activity and levels of uPA, suPAR, and PAI-1 were significantly decreased after SH injections in TMJs of OA patients (P < .05), and there was no difference after saline injection. Visual analog pain score reduction correlated with changes in uPA and uPAR levels as well as uPA activity.

CONCLUSION

The effects of SH on PA system provide new insight into a possible underlying mechanism by which SH alleviates pain of patients with TMJ OA.

Effect of local hyperthermia on lymphangiogenic factors VEGF-C and -D in a nude mouse xenograft model of tongue squamous cell carcinoma

It is widely accepted that tumor-induced lymphangiogenesis driven by vascular endothelial growth factor (VEGF)-C- and/or VEGF-D-induced activation of VEGF receptor (VEGFR)-3 could promote lymphatic metastasis. In this study, tumor growth and intratumoral expression level of VEGF-C and -D following administration of local hyperthermia was evaluated in nude mice model of tongue squamous cell carcinoma (SCC). The data demonstrated that the size of tumor in local hyperthermia was 26.5% of control group, and that local hyperthermia markedly suppressed the mRNA and protein expression of VEGF-C and -D as determined by quantitative real-time RT-PCR, Western blot and immunohistochemistry (P<0.05). These results suggest that, accompanying with tumor growth inhibition, local hyperthermia may act as an anti-lymphangiogenic role by suppressing the expression of tumor VEGF-C and -D, and thereby inhibiting cancer cell lymphatic metastasis in tongue SCC.

Maxillofacial space infection experience in West China: a retrospective study of 212 cases

OBJECTIVES

Our objectives were to analyze the clinical features of maxillofacial space infection (MSI) patients admitted to the West China Hospital of Stomatology over a five-year period, and to identify potential risk factors associated with life-threatening complications.

METHODS

A retrospective medical chart review was performed and the sociodemographic and clinical characteristics of patients with MSI were evaluated.

RESULTS

A total of 212 patients were enrolled in this study, including 125 males (59.0%) and 87 females (41.0%), with an age range of 1-88 years (median 47.5 years). The most common cause of MSI was odontogenic infection (56.1%). The submandibular space was the space most commonly involved in both single space and multiple space infections (37.5% and 29.1%, respectively). One hundred and two patients (48.1%) self-medicated before admission, and the time from onset of symptoms until presentation was longer in those who self-medicated compared with those who did not (p=0.028). Fifty-seven patients (26.9%) had life-threatening complications and six died (2.8%). In multivariate analysis, age, self-medication, admission temperature, respiratory difficulty, and underlying diseases were found to be risk factors for life-threatening complications. The most common occupation of the patients was farmer (54.7%). Among the farmers, 72.4% had an odontogenic etiology; however, 91.7% of the farmers with odontogenic space infections had not undergone dental treatment before admission.

CONCLUSIONS

Our experience suggests that the management of MSI should be more aggressive when the above risk factors are present, in order to avoid life-threatening complications. In addition, considering the poor medical conditions in the rural areas of West China, standard dental care and services should be provided in the future to replace self-medication.

Biocompatible interface films deposited within porous polymers by Atomic Layer Deposition (ALD)

Ultrathin ceramic films were deposited throughout highly porous poly(styrene-divinylbenzene) (PS-DVB) particles using a low-temperature atomic layer deposition (ALD) process. Alumina and titania films were deposited by alternating reactions of trimethylaluminum and H2O at 33 degrees C and of titanium tetrachloride and H2O2 (50 wt % in H2O) at 100 degrees C, respectively. Analytical characterization revealed that conformal alumina and titania films were grown on internal and external polymer surfaces. The improved bioactivity of the polymer substrates was revealed on the basis of the formation of hydroxyapatite (HA) in simulated body fluid. The accelerated formation of HA on the ALD-modified polymer surface was caused by the negatively charged surface provided by the ultrathin ceramic interface. The potential for ALD films to support cell attachment was demonstrated.

RNAi targeting urokinase-type plasminogen activator receptor inhibits metastasis and progression of oral squamous cell carcinoma in vivo

It has been admitted that urokinase-type plasminogen activator receptor (u-PAR) is overexpressed in many human malignant tumors including oral squamous cell carcinoma (OSCC) and plays an important role in a variety of cancer key cellular events as a versatile signaling orchestrator. In our study, a retroviral vector expressing u-PAR-specific siRNA was injected into OSCC xenografts of nude mice to observe its inhibitory effects on OSCC. Our data demonstrate that siRNA targeting u-PAR markedly suppressed tumor growth, reduced the expression of proliferation-related gene, Ki-67 and increased cell apoptosis, accompanying with the efficient and specific inhibition of endogenous u-PAR expression in OSCC. More importantly, the mRNA and protein expression of MMP-2, MMP-9, VEGF-C, VEGF-D and VEGFR-3 that are intimately involved in oral cancer invasion and metastasis, was simultaneously downregulated significantly as determined by quantitative real-time RT-PCR, Western blot and immunohistochemistry; and Gelatin and fibrin zymography showed that MMP-9, MMP-2 and u-PA enzymatic activities were significantly reduced in u-PAR-specific siRNA group, compared to those in control groups. In addition, the expression of MDR-1 gene related to drug resistance was obviously inhibited by silencing of u-PAR. These findings suggest that RNAi targeting u-PAR could effectively inhibit the metastasis and progression of OSCC in vivo. Thus, it may be used as a potent and specific therapy for oral cancer, especially in inhibiting and preventing cancer cell invasion and metastasis.

Atomic layer deposition of quantum-confined ZnO nanostructures

The modulation of optoelectronic properties, such as the bandgap of a pure-component semiconductor material, is a useful ability that can be achieved by few techniques. Atomic layer deposition (ALD) was used here to experimentally demonstrate the ability to deposit films that exhibit quantum confinement on three-dimensional surfaces. Polycrystalline ZnO films ranging from approximately 1.5 to 15 nm in thickness were deposited via ALD using diethylzinc and hydrogen peroxide at 100 degrees C. Conformal, pinhole-free films were deposited on Si wafers and on nanosized spherical SiO(2) particles using an augmented central composite design strategy. Powder x-ray diffraction was used to measure the crystallite size of the films and monitor size evolution on the basis of the number of ALD cycles and thermal annealing post-treatments. The absorbance of the ZnO films on Si wafers and SiO(2) particles was measured using spectroscopic ellipsometry and diffuse transmittance techniques, respectively. Post-deposition annealing steps increased the crystallite size of the films, independently of the coating thickness. The ZnO bandgap was increasingly blue-shifted for films of decreasing crystallite size, approaching +0.3 eV at dimensions of 2-3 nm. The nonlinear bandgap response correlated well with the Brus model. This work represents an experimental demonstration of quantum confinement using ALD on two- and three-dimensional substrates.

[Characteristics and understanding of earthquake injury in oral and maxillofacial region during Wenchuan earthquake]

According to the experience of supplies for earthquake in Wenchuan earthquake, this article analyzed the characteristics of earthquake injury in the oral and maxillofacial region in order to help to deal with earthquake injury in oral and maxillofacial region on massive disasters of China in the future.

Free grafting of autogenous coronoid process for condylar reconstruction in patients with temporomandibular joint ankylosis

OBJECTIVE

This article describes the clinical effects of condylar reconstruction by free grafting of autogenous coronoid process in patients with temporomandibular joint (TMJ) ankylosis.

STUDY DESIGN

Fifteen cases of uni- or bilateral TMJ ankylosis during a 3-year period from March 2004 to March 2007 were surgically treated, and the average observation period was 22 months. All patients were treated by condylar reconstruction of immediate autogenous coronoid process grafts. Temporal muscle myofascial flaps or native articular disc was used as an interpositional tissue. Clinical examination, radiographs, and photographs were used postoperatively to evaluate the grafts and TMJ function.

RESULTS

Satisfactory mouth opening was achieved in 14 cases, and 1 patient showed signs of reankylosis of the joint (20 mm mouth opening). Radiographic examination showed that bone union occurred between the grafts and the ramus in all cases. Some bony resorption of the grafted coronoid process was observed in all patients, but no occlusal changes were noted.

CONCLUSION

Satisfactory clinical outcomes are obtained after the condylar reconstruction by free grafting of autogenous coronoid process. Therefore, autogenous coronoid process may be a suitable bone resource for condylar reconstruction in patients with TMJ ankylosis.

Passivation of pigment-grade TiO(2) particles by nanothick atomic layer deposited SiO(2) films

Pigment-grade TiO(2) particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO(2) and Al(2)O(3) layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO(2) films were deposited using tris-dimethylaminosilane (TDMAS) and H(2)O(2) at 500 °C. Trimethylaluminum and water were used as precursors for Al(2)O(3) ALD at 177 °C. The photocatalytic activity of anatase pigment-grade TiO(2) was decreased by 98% after the deposition of 2 nm SiO(2) films. H(2)SO(4) digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO(2) digest rate was 40 times faster for uncoated TiO(2) than SiO(2) coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H(2)O(2) chemistry can deposit high quality, fully dense SiO(2) films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO(2) particles.

RNAi-mediated downregulation of urokinase plasminogen activator receptor inhibits proliferation, adhesion, migration and invasion in oral cancer cells

RNA interference (RNAi) has emerged as an effective method to target specific genes for silencing. Overexpression of urokinase-type plasminogen activator receptor (uPAR) has been implicated in progression and metastasis of oral cancer. In our study, RNAi was introduced to downregulate the expression of uPAR in the highly malignant oral squamous cell carcinoma (OSCC) cells. Our data demonstrated that siRNA targeting of uPAR leads to the efficient and specific inhibition of endogenous uPAR mRNA and protein expression as determined by quantitative real-time RT-PCR and Western blotting. Furthermore, simultaneous silencing of uPAR resulted in a dramatic reduction of tumor cell proliferation activity, adhesion, migration and invasion in vitro compared to the controls. These findings provide further evidence for the involvement of uPAR in a variety of cancer key cellular events as a versatile signaling orchestrator, and suggest that RNAi-directed targeting of uPAR can be used as a potent and specific therapeutic tool for the treatment of oral cancer, especially in inhibiting and/or preventing cancer cell invasion and metastasis.

Hypoxia inducible factor-alpha expression correlates with vascular endothelial growth factor-C expression and lymphangiogenesis/angiogenesis in oral squamous cell carcinoma

BACKGROUND

The number of blood vessels correlates with metastasis in solid tumors, including oral squamous cell carcinoma (OSCC). Hypoxia inducible factor-1alpha (HIF-1alpha) could play a role in tumor lymphangiogenesis by regulating the lymphatic expression of vascular endothelial growth factor-C (VEGF-C). HIF-1alpha protein expression, VEGF-C protein expression, lymphatic vessel density (LVD) and blood vessel density (BVD) in OSCC were investigated.

MATERIALS AND METHODS

HIF-1alpha and VEGF-C protein expression were investigated by means of immunohistochemistry in samples from 65 cases of OSCC. The density of the lymphatic microvessels and blood microvessels immunohistochemically stained by LYVE-1 and CD34 antibody, respectively, was calculated. The association between the HIF-1alpha expression and the clinicopathological parameters was evaluated.

RESULTS

HIF-1alpha overexpression occurred in 43 out of the 65 tumor samples (66.2%), while VEGF-C overexpression was observed in 34 out of the 65 tumor samples (52.3%). Higher LVD was found in both high HIF-1alpha and high VEGF-C expression cases. HIF-1alpha overexpression was significantly correlated with VEGF-C overexpression (p = .018, Chi-square test), higher LVD (p < 0.001, Mann-Whitney U-test), and regional lymph nodal involvement (p = 0.004, Chi-square test) as well as UICC TMN classification (p = 0.043, Chi-square test), respectively. In addition, higher BVD existed in the high HIF-1alpha and VEGF-C expression groups (p < 0.001, Mann-Whitney U-test).

CONCLUSION

HIF-1alpha might play a crucial role in regional lymph node metastasis as a regulator of lymphangiogenesis and angiogenesis in OSCC with a possible novel pathway involving VEGF-C. Therefore, HIF-1alpha might be a particularly promising target for controlling regional lymph node metastases by a combination of antiangiogenic and anti-lymphangiogenic effects in OSCC.

[Expression of urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor in synovial fluid of patients with temporomandibular disorders]

OBJECTIVE

To investigate the level of urokinase-type plasminogen activator (uPA) and urokinase-type plasminogen activator receptor (uPAR) in synovial fluid of patients with temporomandibular disorders and to analyze their relation with temporomandibular disorders (TMD).

METHODS

Synovial fluid was obtained from 64 sides of 56 TMD patients and from 16 sides of 10 asymptomatic healthy volunteers (control). The concentrations of uPA and uPAR in the synovial fluid were measured by ELISA. Forty-eight sides of TMD were divided into 3 groups: arthrosis, structure disorder and osteoarthrosis, each including 16 sides.

RESULTS

The levels of uPA and uPAR were significantly higher in the synovial fluid of TMD patients than that in the control group (P < 0.05), and the level of uPA and uPAR in osteoarthrosis group was significantly higher than that in arthrosis and structure disorder group (P < 0.05). However, there was no difference in expression of uPA and uPAR between arthrosis and structure disorder groups (P > 0.05).

CONCLUSIONS

uPA and uPAR in the synovial fluid may play a role in the pathogenesis of TMD, and the level of uPA and uPAR in synovial fluid of TMD could be used as a biochemical markers to reflect pathological degree of TMD.