Prolonging Bacterial Viability in Biological Concrete: Coated Expanded Clay Particles

One of the biggest challenges in the development of a biological self-healing concrete is to ensure the long-term viability of bacteria that are embedded in the concrete. In the present study, a coated expanded clay (EC) is investigated for its potential use as a bacterial carrier in biological concrete. Eight different materials for coatings were selected considering cost, workability and accessibility in the construction industry. Long-term (56 days) viability analysis was conducted with a final evaluation of each coating performance. Our results indicate that healing efficiency in biological concrete specimens is strongly related to viable bacteria present in the healing agent. More viable bacteria-containing specimens exhibited a higher crack closure ratio. Our data suggest that the additional coating of EC particles improves long-term bacterial viability and, consequently, provides efficient crack healing in biological concrete.     

大黄素对兔实验性骨折一氧化氮合成酶表达的影响

目的：观察大黄素对骨折愈合过程骨痂中一氧化氮合成酶（NOS）活性的的影响，探讨大黄素对骨折愈合的促进作用。方法：选用40只新西兰白兔，建立桡骨中下段骨折模型，随机分为2组，每组20只，大黄素组腹腔注射大黄素，对照组腹腔注射生理盐水；分别于骨折后4、7、14、21d收集骨痂，通过HE染色行形态学观察，采用Western—blot方法检测骨痂中NOS蛋白表达量，采用NOS酶活性分型试剂盒检测NOS酶活性。结果：大黄素组和对照组骨痂存在明显的形态学差异；大黄素组eNOS表达及活性显著高于对照组；两组间iNOS表达无显著性差异。结论：大黄素通过对eNOS活性表达调控，可以使骨折断端血管增生和成骨能力增强，促进骨折愈合。     

Loose fascial closure and fascial defects: effects on laparotomy healing in rats

Summary Every suture technique in surgery aims at connecting tissue structures until stable scar formation has developed. Although the negative effects of high suture tension on the mechanical properties of the developing scar are well known, the applied suture tension has not been standardized and depends on the surgeon's experience. In this study the effects of low suture tension on laparotomy closure were studied in rats and an incisional hernia model was developed. Median laparotomies were closed by running suture using Foley-catheters with a diameter of 2.4, 4.8 and 7.2 mm as distance holders. In another group, an abdominal wall defect of 2 cm diameter was created and covered internally by larger omentum. After 28 days laparotomies closed using a distance holder with diameter of 2.4 and 4.8 mm had healed without developing fascial dehiscence or incisional hernia. With 7.2 mm catheters all animals developed a ruptured abdomen. All animals with abdominal wall defects developed incisional hernias with stable hernial sacs without significant inflammatory reaction. Laparotomy closure intentionally performed with a surplus of suture material of up to 21% per stitch in a 4 cm incision does not result in a disturbance of wound healing or hernia formation. Creating an abdominal wall defect with an internal covering of great omentum in rats reliably results in incisional hernia formation closely resembling that found in humans. These results underline the necessity to further determine values for tissue-specific suture tension experimentally.     

单侧外固定架动力化对骨折愈合的影响

目的：研究单侧外固定架不同时间动力化对骨折愈合的影响。方法 3组共15只山羊，每只行左侧胫骨横断后，用单侧外固定架固定。各组分别于术后2、4、6周实施动力化，定期摄X线片，行B超检查，生物力学测试，骨折愈合后行三点弯曲试验，组织学检查。结果 4周动力化组优于其他两组。结论 支架适时动力化后可促进骨痂生长，加速骨折愈合进程，骨折术后4周动力化最佳。     

Effects of near-infrared laser exposure in a cellular model of wound healing

Background: Clinical studies have demonstrated beneficial outcomes for low-level laser therapy (LLLT) using near-infrared (NIR) wavelengths. It has been hypothesized that the benefits of NIR LLLT are due in part to the thermal effects of NIR exposure. However, it is not clear whether photochemical interactions between NIR light and superficial tissues contribute to beneficial outcomes. To investigate the photochemical effects of NIR exposure, the efficacy of 980 nm NIR LLLT on human fibroblast growth rates is investigated using an in vitro model of wound healing.
Methods: A small pipette is used to induce a wound in fibroblast cell cultures, which are imaged at specific time intervals over 48 h and exposed to a range of laser doses (1.5–66 J/cm²) selected to encompass the range of doses used during other in vivo and in vitro studies. For each image acquired, wound sizes were quantified using a novel application of existing image processing algorithms.
Results: Cell growth rates were compared across different laser exposure intensities with the same exposure duration, and across different laser exposure durations with the same exposure intensity. Exposure to low- and medium-intensity laser light accelerates cell growth, whereas high-intensity light negated the beneficial effects of laser exposure. Cell growth was accelerated over a wide range of exposure durations using medium-intensity laser light, with no significant inhibition of cell growth at the longest exposure durations used in this study.
Conclusion: Low-level exposure to 980 nm laser light can accelerate wound healing in vitro without measurable temperature increases. However, these results also demonstrate the need for appropriate supervision of laser therapy sessions to prevent overexposure to NIR laser light that may inhibit cell growth rates observed in response to lower intensity laser exposure.     

Does root surface conditioning with citric acid delay healing?

Abstract Effects of topical citric acid application on tissue maturation was studied in standardized periodontal defects in 6 beagle dogs. Following elevation of facial mucoperiosteal flaps, fenestration defects, 3 mm in diameter, were made through the cortical bone and recessed 0.5 mm into the dentin of maxillary canines. 1 defect in each dog was conditioned with a saturated solution of citric acid for 3 min and then rinsed with saline. Control defects in contralateral teeth were treated with saline only for the same length of time. The defects were covered with an expanded polytetrafluoroethylene membrane and the flaps re-positioned and sutured. 14 days postsurgery, healing appeared more advanced along the defect walls and floor than in the center of the defect in all instances. Histometrically, citric acid-conditioned defects exhibited a higher density of collagen fibers along the defect walls and floor and adjacent to the barrier membrane as well as more advanced resolution of the residual blood clot than the surgical controls. Differences in fibroblast density within specimen pairs were non-significant. All control defects but none of the acid-conditioned defects showed an artifactual split between the dentin walls and the granulation tissue. This study failed to support the contention that topical application of citric acid to root surfaces may delay healing following periodontal surgery.     

Influence of tendon healing after arthroscopic rotator cuff repair on clinical outcome using single-row Mason-Allen suture technique: a prospective, MRI controlled study

The reported functional results of rotator cuff repair performed arthroscopically have been good. Only little is known about the cuff integrity after arthroscopic repair and how it influences the outcome. The aim of the study is to set a baseline of what rate of healing response respectively re-tears to expect and how cuff integrity alters the outcome. Fifty-three consecutive patients with an isolated supraspinatus tendon tear were arthroscopically operated and their tendons repaired. All pre- and postoperative data were prospectively collected. At a minimum follow-up after 24 months (average 26.4 months), the integrity of the cuff was evaluated by an open magnetic resonance imaging and the patients’ function and satisfaction were documented and graded to the sex- and age-related Constant-score also using a dynamometer for strength testing. The re-tear rate was 24.5% with 13 non-healed tendons. The Constant-score of all patients improved significantly. The scores of the patients with a re-tear were significantly lower than those of the patient with an intact cuff. That was due to a less good performance in strength testing. The other categories of the Constant-score did not show any differences. The age of the patients with a re-tear was significantly higher. With the exception of age, we did not find any negative prognostic factor for a re-tear, and with the exception of re-tear no other factor influenced the Constant-score. Arthroscopic supraspinatus tendon repair yields a re-tear rate of 25% which is comparable with the results of open or mini/open repair. Cuff integrity influences postoperative strength and Constant-score. Patients older than 65 years show a higher re-tear rate. Therapeutic Level IV is the level of evidence.     

严重粉碎性髌骨骨折的治疗

对于无法行克氏针张力带固定的髌骨严重粉碎性骨折,以往多采用髌骨切除术治疗,疗效差.自1991年以来,我们采用粗丝线荷包缝合术、术后短期石膏托外固定、中药熏洗等综合方法治疗30例,疗效满意,现报告如下.     

神经肽与伤口愈合

创伤愈合时，周围神经释放的神经肽在神经系统与损伤组织之间起着重要信号介导作用。神经肽不仅参与启动愈合早期的神经源炎性反应，并且通过对免疫细胞、修复细胞以及对生长因子网格的作用，调控伤口愈合。调节周围神经功能或在伤口局部应用神经肽，可能成为促进伤口愈合的重要措施。     

Role of mechanical loading in healing of massive bone autografts

We assessed healing of a 3.5 cm autograft transport segment, denuded of periosteum, and docked to the healthy distal femur with an intramedullary nail. We hypothesized that healing relates to proximity to the healthy distal femur and to mechanical loading patterns. Total bone area, area of new bone apposition, and quality of new bone formed in the 2 weeks after surgery, and area and degree of perfusion 16 weeks after surgery were measured as a function of proximity and loading patterns (as defined by the major and minor centroidal axes, CA). At 16 weeks, no significant differences in early bone apposition or perfusion were observed as a function of distance from the healthy distal femur. Qualitatively, bone was well perfused, both vascularly and pericellularly, and highly remodeled. When cross‐sections were pooled from distal to proximal through the docking zone and normalized for total bone area, significant differences in the amount of early proliferative woven bone were related to loading patterns. In contrast, no differences in normalized perfusion area were attributable to loading patterns. Furthermore, early bone apposition and perfusion decreased with increasing radial distance from the bone surface toward the intramedullary nail. Finally, no differences were observed in areas of resorption within the docking zone compared to baseline levels measured in the control (in bone removed to create the defect zone at the time of surgery). Interestingly, infilling of resorption spaces within docking zone specimens related significantly to predominant loading patterns, where areas within the major CA exhibited significantly more infilling. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1657–1664, 2010