Effects of hydroxyapatite and PDGF concentrations on osteoblast growth in a nanohydroxyapatite-polylactic acid composite for guided tissue regeneration

The technique of guided tissue regeneration (GTR) has evolved over recent years in an attempt to achieve periodontal tissue regeneration by the use of a barrier membrane. However, there are significant limitations in the currently available membranes and overall outcomes may be limited. A degradable composite material was investigated as a potential GTR membrane material. Polylactic acid (PLA) and nanohydroxyapatite (nHA) composite was analysed, its bioactive potential and suitability as a carrier system for growth factors were assessed. The effect of nHA concentrations and the addition of platelet derived growth factor (PDGF) on osteoblast proliferation and differentiation was investigated. The bioactivity was dependent on the nHA concentration in the films, with more apatite deposited on films containing higher nHA content. Osteoblasts proliferated well on samples containing low nHA content and differentiated on films with higher nHA content. The composite films were able to deliver PDGF and cell proliferation increased on samples that were pre absorbed with the growth factor. nHA–PLA composite films are able to deliver active PDGF. In addition the bioactivity and cell differentiation was higher on films containing more nHA. The use of a nHA–PLA composite material containing a high concentration of nHA may be a useful material for GTR membrane as it will not only act as a barrier, but may also be able to enhance bone regeneration by delivery of biologically active molecules

Lipofibromatous hamartoma of the median nerve

Lipofibromatous hamartoma is a rare tumour of peripheral nerves which is characterised by an excessive infiltration of the epineurium and perineurium by fibroadipose tissue. To the best of our knowledge, only approximately 88 cases are reported in the literature. We report a rare case of lipofibromatous hamartoma of the median nerve causing secondary carpal tunnel syndrome in a 25 year old patient. This patient was treated conservatively with decompression and biopsy and experienced a complete resolution of symptoms post-operatively. Magnetic resonance imaging may be used to diagnose this lesion as it has very distinctive characteristics. Multiple conditions have been associated with this lesion and a greater understanding of these associations may clarify the pathogenesis. The architecture of the tumour makes excision very challenging and the surgical management remains controversial. A review of the literature regarding the etiology, pathogenesis and surgical management of lipofibromatous hamartoma is included

Sex differences in rheumatoid arthritis: more than meets the eye...

Sex differences in the prevalence of autoimmune diseases such as rheumatoid arthritis (RA) are well described, but the literature is not as clear about sex differences in RA disease course and prognosis. A recent study from a very large cross-sectional international cohort demonstrated slightly worse levels of disease activity and function in female patients with RA, compared with men. These findings are discussed in the context of our evolving knowledge of sex differences in the expression of this prototypic autoimmune disease, both in terms of the actual disease activity level, the effects that the disease has on physical function, and our ability accurately to measure these aspects

Reliability of the Lisfranc injury radiological classification (Myerson-modified Hardcastle classification system)

Purpose The objective of our study was to assess the reliability of the radiological classification system (Myerson-modified Hardcastle Classification System) for Lisfranc injury. The classification system is a three-grade ordinal scale based on fracture displacement. Methods Thirty-nine Lisfranc injury radiographs were evaluated by 38 independent observers consisting of consultant orthopaedic surgeons (18), orthopaedic surgery residents (17) and consultant musculoskeletal radiologists (3) on two separate occasions after receiving training in the use of the classification. Results The intra- and inter-observer reliability was assessed using the intraclass correlation coefficient (ICC) and found to be excellent. The mean weighted intra- and inter-observer ICCs were 0.94 (95 % CI 0.89–0.97, p < 0.01) and 0.81 (95 % CI 0.68–0.89, p < 0.01), respectively. Conclusion The Myerson-modified Hardcastle classification system in our study was shown to be reliable and can be used in outcome studies and provide standard terminology among clinicians for Lisfranc injuries

Evaluating the effect of heat transfer on cell disruption in ultrasound processes

Ultrasound is one of the mechanical methods used for disruption of microorganisms. Ultrasonic treatments of microorganisms are sensitive to a wide range of parameters such as net thermal power, residence time distribution (RTD), and the biological structure of the target microorganism. A commercial ultrasonic processor attached to a stainless steel processing cell was used in this research work. To evaluate the net heat dissipated in a small volume of the commercial yeast Saccharomyces cerevisiae, the suspension was subjected to 117 W at 20 kHz; the ultrasound cell was operated in a batch configuration with a Perspex base. Mixing of the yeast suspension and the RTD were evaluated using image processing techniques. The results of the present study showed that the heat lost through the stainless steel wall, Perspex base, and the Sonotrode (Titanium) was around 13.5% of the total power. The yeast disruption results were found to be positive. The yeast disruption test showed that complete yeast reduction can be achieved at 117 W and a specific energy of 1,146 kJ kg−1. Further study is needed to understand the real causes of microorganism disruption using ultrasound