Prevention of Vascular Anastomotic Stenosis With 2-Octylcyanoacrylate.

Although conventional microvascular anastomoses are well-studied, postoperative anastomotic stenoses remain a common surgical complication. The use of 2-octylcyanoacrylate to stabilize vascular anastomoses using a rabbit anastomosis model was investigated. A carotid artery anastomosis model was established in 20 New Zealand rabbits (2.5-3.0 kg): 10 underwent conventional anastomosis surgery with sutures only, while 10 underwent suture ligation, followed by the application of 2-octylcyanoacrylate. Vascular patency and pulse strength were observed after adhesive solidification. The artery diameter was measured preoperatively and at 5 minutes, 2 weeks, and 4 weeks postoperatively. An angiography was performed at 4 weeks postoperatively. Hyperplasia and the induced nitric oxide synthase (iNOS) content of the intima and media layers from the anastomotic stoma were assessed using immunohistochemistry. The artery inner diameter of experimental group decreased at each time point postoperatively (1.686 ±â€Š0.066 cm; 1.656 ±â€Š0.069 cm; 1.646 ±â€Š0.074 cm) (P ≤ 0.01). At 4 weeks postoperatively, the intima and the media around the anastomosis was both significantly thinner in the experimental group (13.21 ±â€Š0.84 µm; 234.86 ±â€Š13.84 µm) than in the control group (17.06 ±â€Š0.96 µm; 279.88 ±â€Š34.22 µm) (P < 0.05). At 4 weeks postsurgery, intravascular iNOS expression was increased in both groups but was higher in the experimental group (82.5% versus 47.5%). The above results indicated that 2-octylcyanoacrylate adhesive can inhibit stenosis of vascular anastomoses.

Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation.

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

Derivation and growth characteristics of dental pulp stem cells from patients of different ages.

The dental pulp contains a relatively low number of stem cells; however, it is considered to be a promising source of stem cells for use in regenerative therapy. To date, it has remained elusive whether there are certain differences in the dental pulp stem cells (DPSCs) from donors of different ages. In the present study, DPSC lines were derived using teeth from children, adolescents, adults and aged donors. The derivation efficiency, the proliferative and apoptotic rate, cell marker expression and the differentiation capacity were investigated and compared among these DPSC lines. The derivation efficacy was decreased with increasing donor age. Although a large part of cell surface markers was expressed in all DPSC lines, the expression of CD29 was downregulated in the DPSCs from aged teeth. In addition, the doubling time of DPSCs from aged teeth was prolonged and the number of apoptotic cells was increased with the propagation. These DPSCs were able to differentiate into a neuronal linage, which positively expressed the neuron-specific class III beta-tubulin and microtubule­associated protein 2, as well as into an osteogenic lineage, which positively expressed CD45; however, these DPSCs from aged teeth were completely or partially deprived of differentiation capacity. By contrast, DPSCs from younger teeth displayed significantly higher vitality and a higher potential for use in dental regenerative medicine.

A novel method of defective vascular reconstruction using 2-octyl-cyanoacrylate and homemade prosthetic component.

BACKGROUND: Currently, adhesive technique is popular in vascular repair but not widely used for defective vessels. This study aimed to determine the feasibility and effectiveness of repairing defective vessels with 2-octyl-cyanoacrylate and a homemade prosthetic component. METHODS: Homemade prosthetic component consisting of expanded polytetrofluoroethylene (ePTFE), terylene film, and homemade soluble hollow stent mixed with adhesive can replace autologous graft and suture in repairing defective vessels, can fix vessels better using the stent without occlusive bleeding. Forty male mongrel dogs were used, 20 for biomechanical tests and 20 for animal experiments. In the biomechanical test, dogs were randomly divided into two groups (n = 10 each), one group repaired on the two sides of the carotid arteries with 2-octyl-cyanoacrylate and homemade component and another group repaired with suture and ePTFE. Of the 40 specimens, 10 were used for adhesive and 10 for suture specimens for tension strength test, whereas the remaining specimens were used for bursting pressure test. In animal experiments, dogs were also divided into adhesive and suture groups (n = 10), only of the left carotid artery. Recording the operational time, bleeding or not. Vessels were tested using color Doppler ultrasound, the inner diameter was measured, and the degree of stenosis at 8 weeks was evaluated digital subtraction angiography (DSA) were also performed. Specimens were then analyzed histologically. RESULTS: In the adhesive and suture groups, the specimens could afford atension strength of (23.80 ± 1.51) N versus (24.60 ± 1.08) N (P > 0.05), the bursting pressure was (52.03 ± 2.43) kPa versus (50.04 ± 3.51) kPa (P > 0.05), and the mean time of anastomosis was (15.20 ± 0.55) minutes versus (25.97 ± 0.58) minutes (P < 0.05). One dog in the adhesive group was bleeding from the suture. One dog from each group presented with thrombosis at 1 week. After measuring using ultrasound, the stenosis degree of all dogs were no more than 30% except the two thromboses. DSA and histological observation showed no obvious difference between the two groups. CONCLUSION: Defective vascular anastomosis with 2-octyl-cyanoacrylate and our homemade prosthetic component is feasible, effective, timesaving, and easy to master.

Effect of seawater salinity on pore-size distribution on a poly(styrene)-based HP20 resin and its adsorption of diarrhetic shellfish toxins.

In the present study, okadaic acid (OA) and dinophysistoxin-1 (DTX1) were spiked into artificial seawater at low, medium and high estuarine salinities (9‰, 13.5‰ and 27‰). Passive samplers (HP20 resin) used for solid phase adsorption toxin tracking (SPATT) technology were exposed in these seawaters for 12-h periods. Adsorption curves well fitted a pseudo-secondary kinetics model. The highest initial sorption rates of both toxins occurred in the seawater of medium salinity, followed by seawater of low and high estuarine salinity. Pore volumes of micropores (<2 nm) and small mesopores (2 nm

Experimental study on new self and mutual-aiding occlusive dressing for wound.

BACKGROUND: Self and mutual-aiding occlusive dressing is a novel method to treat with the wounds in special circumstances. This study aims to prepare a new antimicrobial adhesive for the dressing and evaluate the application effects of the adhesive. METHODS: The main component of the new antimicrobial adhesive was 5% triclosan / cyanoacrylate (CA) antimicrobial adhesive. The adhesive was modified with carboxylic multi-walled carbon nanotubes (MWCNTs-COOH), multi-walled carbon nanotubes (MWCNTs), hydrophobic nano-silica, nitrile rubber, epoxy resin and polymethyl methacrylate (PMMA) respectively. The bond strength, toughness and viscosity of the modified adhesive in different concentrations were examined to select the optimal modifying material and the best ratio to prepare the new antimicrobial adhesive according to the results. After that, the antimicrobial property of the new antimicrobial adhesive was tested by filter paper method. At last, we disposed the injury models in rats using the new antimicrobial adhesive to examine the application effects. RESULTS: In individual tests, the bond strength modification performance of 0.064% MWCNTS-COOH is the best, the bond strength is (14.71 ± 1.48) Mpa. 8% nano-silica shows the best toughness modification performance, the Tg is (1.10 ± 0.24)°C. The viscosity modification performance of 8% nano-silica is the best, the viscosity is (15 536.68 ± 28.4) cP. However, consolidating three test results, 6% nano-silica/antimicrobial adhesive has the balanced bond strength, toughness and viscosity. Its bond strength is (14.03±1.92) Mpa, the Tg is (3.60 ± 0.68)°C, and the viscosity is (5 278.87 ± 31.68) cP. The inhibition zone diameter of 6% nano-silica/antimicrobial adhesive and antimicrobial adhesive group in Day 5 is (28.61 ± 0.91) mm versus (28.24 ± 2.69) mm (P > 0.05). In animal studies, both in blood routine test and pathological section, 6% nano-silica/antimicrobial adhesive group shows lower white blood cells count than gauze bandage group (P < 0.05). CONCLUSIONS: 6% nano-silica has the optimal effect of bond strength modification, toughness modification and viscosity modification, and the antimicrobial adhesive modified with it has a good antimicrobial property (resistant staphylococcus aureus).

[Finite element study of maxillary Le Fort-I osteotomy with rigid internal fixation].

OBJECTIVE: To study the biomechanical characteristic of maxillary Le fort- I osteotomy with rigid internal fixation (RIF) , so as to choose best fixation method. METHODS: The 3-dimensional finite element models of maxillary Le Fort-I osteotomy with 9 kinds of RIF methods were established. Then the models were divided into three groups to calculate the stress distribution of the maxilla and the displacement of bone segment under 3 kinds of occlusion condition. The fixation stability of the different RIF methods was evaluated. RESULTS: Under the incisor occlusion condition, the stress of the cranio maxillary complex transmits mainly along the nasal-maxillary buttress. Under the premolar and molar occlusion condition, the stress transmits along the alveolar process first, then turns to the nasal-maxillary and zygomatic-maxillary buttress. The focused stress position of the internal fixation system is at the connection between the screws and the plate and at the plate near the osteotomy line. Under the premolar occlusion condition, the displacement of bone segment with different RIF methods was (in a decreasing order) 0.396509 mm (with bio-absorbable plate), 0.148393 mm (with micro-plate ), 0.078436 mm (with mini-plate) in group 1; 0.188791 mm (fixing at the nasal-maxillary buttress), 0.121718 mm (fixing at the zygomatic-maxillary buttress), 0.078436 mm (fixing at the both buttress) in group 2; 0.091023 mm (with straight plate), 0.078436 mm (with L shape plate), 0.072450 mm (with Y shape plate), 0.065617 mm (with T shape plate) in group 3. CONCLUSIONS: The fixation stability of using the bio-absorbable plate in Le Fort-I osteotomy is less stable than using the titanium plate. Fixing at the zygomatic-maxillary buttress is more stable than at the naso-maxillary buttress. The fixation stability is different by using different shapes of plates.

[Establishment and primary analysis of the three-dimensional finite element model of mandibular bilateral sagittal split ramus osteotomy with rigid internal fixation].

OBJECTIVE: Establish the three-dimensional finite element models of mandibular bilateral sagittal split ramus osteotomy (BSSRO) with rigid internal fixation (RIF), for further study of BSSRO. METHODS: CT scanned technology and the finite element software (ANSYS) were used to establish the original three-dimensional model of mandible, modify the model to animate the BSSRO, then establish the model of RIF, last mesh the model to establish the finite element model of BSSRO with RIF. Apply 100 N occlusion force at the central incisor; calculate the stress distribution of the mandible and the RIF. RESULTS: Three-dimensional finite element models of BSSRO with RIF were established, such as miniplate model, bicortical fixation screw model. When biting with the incisor and fixed with upper plate, the stress of the medial screw position of the distal and medial segment of mandible is high. When fixed with bicortical fixation screw, the highest stress position located at the internal surface of the medial screw' s position of the distal segment of mandible. CONCLUSIONS: The mentioned methods proved feasible in establishing the finite element models of BSSRO with RIF . The models can be applied to the study of BSSRO with RIF.