Complications of total hip arthroplasty: periprosthetic fractures of the acetabulum

Periprosthetic fractures of the acetabulum are a rare but potentially disastrous complication of total hip arthroplasty. Such fractures occur either as early perioperative complications or late complications when they are associated with either significant trauma or as a result of the loss of the structural integrity of the bone supporting the prosthesis, such as aseptic osteolysis. The incidence of such fractures appears to be increasing with the increased use of uncemented acetabular components. This article explores the current literature on the epidemiology, etiology, and classification of periprosthetic acetabular fractures as well as offering potential treatment strategies.     

Hyaluronic acid skin fillers: Adverse reactions and skin testing

BACKGROUND: Hyaluronic acid (HA) fillers have been proposed as alternatives to other temporary skin fillers, such as bovine collagen, for treating facial skin lines and for providing lip augmentation. Several types of commercial HA fillers are now available in many countries. They include Restylane, which is produced by microbiologic engineering techniques, and Hylaform, which is HA extract derived from rooster combs. They have been approved for use in several countries, but not currently in the United States. There are no recommendations to perform pretreatment skin testing by the manufacturers. OBJECTIVE: Our purpose is to describe and comment on our experiences with Hylaform and Restylane fillers. Observation of any side effects and skin testing results were documented. METHODS: Between September 1996 and September 2000, 709 patients were treated with Hylaform and Restylane and were followed up clinically for at least 1 year. Three of these patients (0.42%) developed delayed skin reactions. Three other patients were referred for evaluation of their skin reactions from other practitioners. Five of these 6 patients agreed to skin testing of their forearms. RESULTS: In the 5 patients tested, challenge intradermal skin testing was positive in 4 patients; the reactions started approximately 8 weeks after injection. CONCLUSIONS: There was a slight incidence of delayed inflammatory skin reactions to two HA fillers. Both of these reactions occurred after the first and repeat injections. Challenge skin testing was positive in 4 of 5 tested patients.     

Psychological Distress for African-American Adolescent Males: Exposure to Community Violence and Social Support as Factors

This study examined exposure to community violence and depressive and post-traumatic stress disorder (PTSD) symptoms within a non-random sample of low-income, African-American male adolescents. The moderating effect of social support on these relationships was also examined. Seventy-seven African-American adolescent males were recruited from an inner-city, Midwestern high school and surveyed on exposure to violence, depression, post-traumatic stress, and social support. Regression analyses revealed that exposure to violence was significantly associated with both depressive and PTSD symptoms. However, social support was not found to moderate the relationship between exposure to community violence and psychological distress. Implications for intervention are discussed.     

Cytotoxic and photocatalytic studies of hexagonal boron nitride nanotubes: a potential candidate for wastewater and air treatment

Boron nitride (BN) nanomaterials are rapidly being investigated for potential applications in biomedical sciences due to their exceptional physico-chemical characteristics. However, their safe use demands a thorough understanding of their possible environmental and toxicological effects. The cytotoxicity of boron nitride nanotubes (BNNTs) was explored to see if they could be used in living cell imaging. It was observed that the cytotoxicity of BNNTs is higher in cancer cells (65 and 80%) than in normal cell lines (40 and 60%) for 24 h and 48 h respectively. The influence of multiple experimental parameters such as pH, time, amount of catalyst, and initial dye concentration on percentage degradation efficiency was also examined for both catalyst and dye. The degradation effectiveness decreases (92 to 25%) as the original concentration of dye increases (5–50 ppm) due to a decrease in the availability of adsorption sites. Similarly, the degradation efficiency improves up to 90% as the concentration of catalyst increases (0.01–0.05 g) due to an increase in the adsorption sites. The influence of pH was also investigated, the highest degradation efficiency for MO dye was observed at pH 4. Our results show that lower concentrations of BNNTs can be employed in biomedical applications. Dye degradation properties of BNNTs suggest that it can be a potential candidate as a wastewater and air treatment material.

Photocatalytic degradation studies of methyl orange using BNNTs.     

Graphene oxide based crosslinker for simultaneous enhancement of mechanical toughness and self-healing capability of conventional hydrogels

Extraordinary self-healing efficiency is rarely observed in mechanically strong hydrogels, which often limits the applications of hydrogels in biomedical engineering. We have presented an approach to utilize a special type of graphene oxide-based crosslinker (GOBC) for the simultaneous improvement of toughness and self-healing properties of conventional hydrogels. The GOBC has been prepared from graphene oxide (GO) by surface oxidation and further introduction of vinyl groups. It has been designed in such a way that the crosslinker is able to form both covalent bonds and noncovalent interactions with the polymer chains of hydrogels. To demonstrate the efficacy of GOBC, it was incorporated in a conventional polyacrylamide (PAM) and polyacrylic acid (PAA) hydrogel matrix, and the mechanical and self-healing properties of the prepared hydrogels were investigated. In PAM-GOBC hydrogels, it has been observed that the mechanical properties such as tensile strength, Young''s modulus, and toughness are significantly improved by the incorporation of GOBC without compromising the self-healing efficiency. The PAM-GOBC hydrogel with a modulus of about 0.446 MPa exhibited about 70% stress healing efficiency after 40 h. Whereas, under the same conditions a PAM hydrogel with commonly used crosslinker N,N′-methylene-bis(acrylamide) of approximately the same modulus demonstrated no self-healing at all. Similar improvement of self-healing properties and toughness in PAA-GOBC hydrogel has also been observed which demonstrated the universality of the crosslinker. This crosslinker-based approach to improve the self-healing properties is expected to offer the possibility of the application of commonly used hydrogels in many different sectors, particularly in developing artificial tissues.

Introduction of a two-dimensional graphene oxide-based crosslinker simultaneously improve the mechanical and self-healing properties of hydrogels by offering an interesting combination of covalent and reversible hydrogen bonds to polymer backbones.     

Monodisperse magnetic lecithin-PFP submicron bubbles as dual imaging contrast agents for ultrasound (US) and MRI

Multimodal imaging is a recent idea of combining two or more imaging methods synergistically to overcome the weakness of individual imaging modalities and utilizing complementary benefits. Ultrasound (US) and magnetic resonance imaging (MRI) are widely used imaging techniques in healthcare and to fully utilize the potential of fusion imaging, dual-modal contrast agents are necessary to improve disease diagnosis by enhancing contrast resolution and reducing health risks associated with the dual dosage of contrast agents. In this study, magnetic microbubbles were synthesized by incorporating oleic acid stabilized superparamagnetic iron oxide nanoparticles (OA-SPIONs) into lecithin microbubbles, encapsulating the perfluoropentane (PFP) core. The magnetic microbubbles were characterized by FTIR, SEM, MFM, zeta potential, in vitro MRI, and ultrasound. Upon in vitro MRI, magnetic microbubbles showed a negative contrast effect by producing darker T2 weighted images. Magnetic microbubbles showed concentration-dependent response with a decrease in signal intensity with an increase in the concentration of OA-IONP in microbubbles. However, a decrease in acoustic enhancement was also observed with an increase in OA-IONP concentration, therefore concentration was optimized to achieve the best effect on both modalities. The magnetic lecithin microbubble with 10 mg SPIONs provided the best contrast on both US and MR imaging. The hemocompatibility testing resulted in hemolysis less than 7% with plasma recalcification time and thrombin time of 240 s and 6 s corresponding to excellent hemocompatibility. Thus the magnetic microbubbles with a phase convertible PFP core encapsulated by a lecithin shell loaded with OA-SPIONs can serve as a potential bimodal contrast agent for both US and MRI imaging.

The magnetic microbubbles with phase convertible PFP core encapsulated by lecithin shell loaded with OA-SPIONs can serve as a potential bimodal contrast agent for both ultrasound (US) and magnetic resonance imaging (MRI).     

便秘宁对便秘小鼠排便作用的影响

目的 探讨便秘宁对便秘小鼠排便作用的影响。方法 观察不同剂量的便秘宁对正常小鼠、燥结失水便秘模型小鼠肠运动的影响。结果 与对照组相比，不同剂量便秘宁颗粒使燥结失水便秘模型小鼠碳末推进率明显提高（P〈0．01），首次捧便时间明显缩短（P〈0．01），8小时内排便粒数增多（P〈0．05），并能使DC便秘模型小鼠12小时内干、稀粪点数明显增多（P〈0．05）。而大剂量便秘宁颗粒对燥结失水模型及DC模型上述指标与聚乙二醇4000（PEG4000）组相比差异有显著性（P〈0．05）。论讨 便秘宁颗粒能增强便秘小鼠肠运动，大剂量便秘宁对便秘模型小鼠排便作用优于聚乙二醇4000。