Surface hardening of Ti-Al-V superalloy spinal implant by using the boronization method.

BACKGROUND: We compared the raw Ti-Al-V super alloy transpedicular implant screws with boronized and surface-hardened transpedicular implant screws. OBJECTIVE: To improve patients' postoperative prognosis with the production of harder and less fragile screws. METHODS: Surface hardening was achieved by applying green-body encapsulation of the specimen with elemental boron paste which is sintered at elevated temperatures to ensure the boron-metal diffusion. Boron transported into the Ti-Al-V super alloy matrix gradually while suppressing aluminum and a homogeneously boronized surface with a thickness of ∼15 microns was obtained. The uniform external shell was enriched with TiB2, which is one of the hardest ceramics. The Ti-Al-V core material, where boron penetration diminishes, shows cohesive transition and ensures intact core-surface structure. RESULTS: Scanning electron microscope images confirmed a complete homogeneous, uniform and non-laminating surface formation. Energy-dispersive X-ray monitored the elemental structural mapping and proved the replacement of the aluminum sites on the surface with boron ending up the TiB2. The procedure was 8.6 fold improved the hardness and the mechanical resistance of the tools. CONCLUSIONS: Surface-hardened, boronized pedicular screws can positively affect the prognosis. In vivo studies are needed to prove the safety of use.

Suppression of Aquaporin-4 By Antisense Oligonucleotides Reduces Brain Edema In Experimental Traumatic Brain Injury.

AIM: In this study, suppression of Aquaporin-4 (AQP4) synthesis via intracerebroventricular (i.c.v.) injection of antisense oligonucleotide after focal cortical contusion injury in mice was investigated. MATERIAL AND METHODS: 12-week female Swiss albino mice of 20-25 g were used to create a focal cortical contusion model by the weight drop method (35 grams blunt weight, 70 cm height) onto the parietal cortex after craniectomy. The sham group underwent craniectomy without trauma. In the control group, weight was dropped onto the parietal cortex immediately after Dulbecco\'s Modified Eagle Medium (DMEM) i.c.v. injection following craniectomy. In addition, 1 nM of aquaporin-4 (AQP4) antisense oligonucleotide (ASO) was injected via i.c.v route immediately after trauma (0 hours) and 4 hours after trauma. All animals underwent magnetic resonance (MR) imaging and were sacrificed at 24 h. Brain water content was determined using the wet/dry weight method. RESULTS: In the sham group, the average percentage of brain water content was 77.75% compared to the control group with 79.87%. The difference was statistically significant (*p=0.017). In the therapy group, the average was 78.81% and significantly reduced compared to the control group (*p=0.026) at 0 hours. In the 4-hour treatment group, the average of 79.11% was not statistically significant (p=0.39). MR imaging findings also showed a substantial reduction in brain edema in the 0-hour treatment group. However, the 4-hour treatment results, when compared with the control trauma group, did not show a significant difference. CONCLUSION: This study demonstrated that AQP4 antisense oligonucleotide therapy, when administered early after diffuse traumatic brain injury, leads to a significant reduction in brain edema.

Comparison of the Effects of Contractubex Gel and Benzothiazole After Topical Application in an Experimental Model of Epidural Fibrosis in Rats.

BACKGROUND: Postoperative epidural adhesion is a frequent cause of failed back surgery syndrome, manifesting with back and leg pain or neurologic deficits. Development of preventive measures for epidural adhesion after laminectomy is critical to improve outcomes of lumbar surgery. We hypothesized that positive effects of topical application of Contractubex (CTX) gel and benzothiazole (BT) individually and in combination could aid in preventing epidural fibrosis in a rat laminectomy model. METHODS: Rats were randomly assigned to 2 control and 5 experimental groups (n = 8 for each group). The control(-) group received no surgery, whereas the control(+) group underwent laminectomy without any drug administration. In experimental groups, study agents applied to dura mater after laminectomy were 100mgCTX, 2.5%BT, 5%BT; 100mgCTXplus2.5%BT, and 100mgCTXplus5%BT. Laminectomy was performed at the L3 level for all rats. The extent of epidural fibrosis was assessed 4 weeks later macroscopically and histopathologically. Hepatic and renal toxicity of study drugs was assessed histopathologically. RESULTS: Topical CTX and BT individually and in combination reduced epidural fibrosis after laminectomy in rats. Although a meaningful decrease of epidural fibrosis with individual application of CTX and BT (2.5% or 5%) was obtained (P < 0.05), the effect of their combination was more pronounced without meaningful hepatic and renal toxicity (P < 0.05). CONCLUSIONS: Combined use of topical CTX and BT could be a potential therapy for epidural fibrosis. Further research with this agents for the prevention of epidural fibrosis is warranted.

Regenerative potential of chitosan-coated poly-3-hydroxybutyrate conduits seeded with mesenchymal stem cells in a rat sciatic nerve injury model.

OBJECTIVES: A number of chemical and biological factors, including mesenchymal stem cells (MSCs), have been developed to enhance nerve regeneration by introduction through a variety of nerve conduits. This study was designed to assess the efficacy of using chitosan-coated poly-3-hydroxybutyrate (PHB) nerve conduits seeded with human bone marrow-derived MSCs (hMSC-bm) to augment repair in an experimental rat model of sciatic nerve injury. METHODS: A total of 30 rats were randomly assigned to one of three groups (n = 10). In each rat, a 10 mm segment of the sciatic nerve was removed and was replaced by a chitosan-coated PHB conduit seeded with hMSC-bm (PHB/chitosan-hMSC-bm group), a chitosan-coated PHB conduit (PHB/chitosan group), or an autograft (autograft group) as the control. The results were evaluated 8 weeks postoperatively by observation, electromyography and histologic examination with light microscopy and immunostaining. RESULTS: Histologic examination showed that both PHB/chitosan-hMSC-bm conduits and PHB/chitosan conduits led the damaged axons through the injured area. When the effects were compared, the results with the PHB/chitosan-hMSC-bm conduits were superior to those with the PHB/chitosan conduits (p < 0.05) but not as successful as with the autologous nerve grafts (p < 0.05). CONCLUSION: PHB/chitosan-hMSC-bm nerve conduits may be a useful artificial guide for nerve regeneration.