Effect of surface roughness of the titanium alloy Ti-6Al-4V on human bone marrow cell response and on protein adsorption.

The World Health Organization (WHO) has released new guidelines [1] for reducing health care associated infections related to surgery. The new guidelines include 29 concrete recommendations distilled by 20 of the world’s leading experts from 26 reviews of the latest evidence. The recommendations are designed to address the increasing burden of health care associated infections on both patients and health care systems globally. The guidelines include 13 recommendations for the period before surgery, and 16 for preventing infections during and after surgery. They range from simple precautions such as ensuring that patients bathe or shower before surgery and the best way for surgical teams to clean their hands, to guidance on when to use antibiotics to prevent infections, what disinfectants to use before incision, and which sutures to use.

Global Guidelines for the Prevention of Surgical Site Infection

The aim of this systematic review was to determine if eccentric exercise is superior to concentric exercise in stimulating gains in muscle strength and mass. Meta-analyses were performed for comparisons between eccentric and concentric training as means to improve muscle strength and mass. In order to determine the importance of different parameters of training, subgroup analyses of intensity of exercise, velocity of movement and mode of contraction were also performed. Twenty randomised controlled trials studies met the inclusion criteria. Meta-analyses showed that when eccentric exercise was performed at higher intensities compared with concentric training, total strength and eccentric strength increased more significantly. However, compared with concentric training, strength gains after eccentric training appeared more specific in terms of velocity and mode of contraction. Eccentric training performed at high intensities was shown to be more effective in promoting increases in muscle mass measured as muscle girth. In addition, eccentric training also showed a trend towards increased muscle cross-sectional area measured with magnetic resonance imaging or computerised tomography. Subgroup analyses suggest that the superiority of eccentric training to increase muscle strength and mass appears to be related to the higher loads developed during eccentric contractions. The specialised neural pattern of eccentric actions possibly explains the high specificity of strength gains after eccentric training. Further research is required to investigate the underlying mechanisms of this specificity and its functional significance in terms of transferability of strength gains to more complex human movements.

https://bjsm.bmj.com/content/bjsports/43/8/556.full.pdf

The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis

This invention relates to a mixing and delivery device suitable for delivering injectable biomaterials, and to preferred bone cement formulations.

Vertebroplasty injection device

Animal models in spine research are often criticized for being irrelevant to the human situation due to the horizontal position of the spine. Whether this is justified from a biomechanical point of view can be questioned. The purpose of the study reported here was to provide arguments that a quadruped can be a valuable in vivo model for the study of the spine in spite of its horizontal position. Relevant literature is reviewed, and biomechanical analyses were made of the standing and walking quadruped. Further, the vertebral trabecular bone architecture was quantitatively analysed by computer and interpreted in the light of Wolff's law. Due to the fact that spinal segments cannot withstand substantial bending moments, additional tensile forces from muscles and ligaments are necessary to control the posture of a quadruped spine. As a consequence, the spine is mainly loaded by axial compression. The trabeculae in a goat's vertebral body were found to course horizontally between its anterior and posterior endplates, implying that the main load within the vertebral body was indeed an axial compression force. The density of the vertebrae of quadrupeds is higher than that of human vertebrae, suggesting that the quadruped has to sustain higher axial compression stresses. The quadruped spine is mainly loaded along its long axis, just like the human spine. The quadruped can thus be a valuable animal model for spine research. An important point of difference is the higher axial compression stress in quadrupeds, which leads to higher bone densities in the vertebrae. This puts some limitations on the transferability of the results of animal experiments to the human situation.

The use of a quadruped as an in vivo model for the study of the spine - biomechanical considerations.

Staphylococcus aureus is the principal causative agent of the inflammatory bone disease osteomyelitis. Unfortunately, the pathogenesis of this often chronic infection is poorly understood and is complicated by the recent observation that bone-forming osteoblasts can harbor S. aureus. Such an infection presents a significant challenge for the host immune response, because osteoblasts are not known to initiate protective cell-mediated immune responses. Cultured mouse and human osteoblasts infected with S. aureus were found to express high levels of interleukin (IL)-6 and IL-12p75, on the basis of complementary investigations demonstrating both S. aureus-induced up-regulation of expression of IL-6 and IL-12p40 mRNA and secretion of IL-6 and IL-12p75 by these cells. Additionally, a quantitative bioassay demonstrated that IL-12p75 secreted after infection was biologically active. These studies are the first to demonstrate induced IL-12p75 expression by osteoblasts and suggest a previously unrecognized role for osteoblasts in initiating immune responses after S. aureus infection.

Staphylococcus aureus Infection of Mouse or Human Osteoblasts Induces High Levels of Interleukin-6 and Interleukin-12 Production

Irrigating wounds with solutions of antiseptic or antibiotic agents is routinely performed in orthopaedic surgery to reduce the incidence of microbial infection. The effects of these agents on healthy bone tissue is unknown. Three commonly employed antiseptic agents (hydrogen peroxide, Betadine solution, Betadine scrub) and one antibiotic solution (bacitracin) were tested on tibiae and osteoblasts isolated from embryonic chicks. Osteoblast function was evaluated by glycolytic energy metabolism (lactate production), cell number (DNA content), and collagen synthesis ([3H]proline hydroxylation). Two series of experiments were performed. To study concentration-related effects, tibiae or cells were exposed to a range of concentrations of the agents (diluted in saline, 0.9% NaCl) for 2 min, rinsed with saline, and incubated for 24 h in medium containing [3H]proline. For the recovery study, the cells were exposed to an effective, but nonlethal, concentration of the antiseptic agents for 2 min, rinsed with saline, and the incubation was continued in complete culture medium for 6, 12, 24, 48, or 72 h with [3H]proline added for the final 6 h. Solutions containing the antiseptic agents were cytotoxic to both bones and cells at concentrations well below those used clinically in irrigation solutions. In contrast, bacitracin at the concentrations tested was safe for osteoblasts and tibiae. These results suggest that the use of irrigation solutions containing H2O2, Betadine solution, or Betadine scrub on exposed bone tissue should be considered with caution.

Toxic Effects of Wound Irrigation Solutions on Cultured Tibiae and Osteoblasts

The effect of medium pH on the activity of cultured human osteoblasts was investigated in this study. Osteoblasts derived from explants of human trabecular bone were grown to confluence and subcultured. The first-pass cells were incubated in Hepes-buffered media at initial pHs adjusted from 7.0 to 7.8. Osteoblast function was evaluated by measuring lactate production, alkaline phosphatase activity, proline hydroxylation, DNA content, and thymidine incorporation. Changes in medium pH were determined from media pHs recorded at the beginning and end of the final 48 h incubation period. As medium pH increased through pH 7.6, collagen synthesis, alkaline phosphatase activity, and thymidine incorporation increased. DNA content increased from pH 7.0 to 7.2, plateaued from pH 7.2 to 7.6, and increased again from pH 7.6 to 7.8. The changes in the medium pH were greatest at pHs 7.0 and 7.8, modest at pHs 7.4 and 7.6, and did not change at 7.2, suggesting that the pHs are migrating towards pH 7.2. Lactate production increased at pH 7.0 but remained constant from 7.2 to 7.8. These results suggest that in the pH range from 7.0–7.6 the activity of human osteoblasts increases with increasing pH, that this increase in activity does not require an increase in glycolytic activity, and that pH 7.2 may be the optimal pH for these cells. J. Cell. Biochem. 68:83–89, 1998. © 1998 Wiley-Liss, Inc.

Extracellular pH modulates the activity of cultured human osteoblasts.

Summary
Women participated in 5 months of unilateral concentric (n = 37) or eccentric (n = 33) isokinetic resistance training of the legs and arms. Limb muscular strength increased as did total body, leg, and arm fat-free soft tissue mass, total body BMC, hip BMD, and forearm BMC and BMD. Isokinetic training benefits bone mineral acquisition.

Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women

This study investigates the efficacy of using hydrogen peroxide as adjuvant therapy after extended local curettage for benign giant cell tumors of bone. Hydrogen peroxide is used clinically as a chemical adjuvant for removal of residual tumor cells, presumably by effervescent cleansing with minimal damage to surrounding soft tissue and bone cells. This investigation examined the effects of hydrogen peroxide on giant cell tumor cells and osteoblasts grown in culture. Fresh fragments of histologically confirmed giant cell tumor tissue (six patients) and trabecular bone (one patient) were excised. Cells obtained from the fragments were grown in culture. Confluent cell cultures were exposed to saline (control) or hydrogen peroxide (0.1-1000 mm) for 2 minutes, and incubation was continued for 12, 24, or 48 hours without hydrogen peroxide. Protein content, deoxyribonucleic acid content, tartrate resistant acid phosphatase activity, and alkaline phosphatase activity were measured in the cell layers. The medium from the final 12 hours of each incubation period was used to evaluate lactate production. Cell lysis or death occurred after exposing giant cell tumor cells and osteoblasts to 100 mm and 30 mm hydrogen peroxide, respectively, concentrations substantially lower than the 3% (880 mm) hydrogen peroxide commonly used clinically. These results support the theory of using a minimal concentration of hydrogen peroxide as a chemical adjuvant in the surgical treatment of giant cell tumors of bone.

Warren K. Ramp

Papers

Staphylococcus aureus Infection of Mouse or Human Osteoblasts Induces High Levels of Interleukin-6 and Interleukin-12 Production

Toxic Effects of Wound Irrigation Solutions on Cultured Tibiae and Osteoblasts

Extracellular pH modulates the activity of cultured human osteoblasts.

Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women

Hydrogen peroxide inhibits giant cell tumor and osteoblast metabolism in vitro.