Particle size and morphology of UHMWPE wear debris in failed total knee arthroplasties--a comparison between mobile bearing and fixed bearing knees.

Osteolysis induced by ultrahigh molecular weight polyethylene wear debris has been recognized as the major cause of long-term failure in total joint arthroplasties. In a previous study, the prevalence of intraoperatively identified osteolysis during primary revision surgery was much higher in mobile bearing knee replacements (47%) than in fixed bearing knee replacements (13%). We postulated that mobile bearing knee implants tend to produce smaller sized particles. In our current study, we compared the particle size and morphology of polyethylene wear debris between failed mobile bearing and fixed bearing knees. Tissue specimens from interfacial and lytic regions were extracted during revision surgery of 10 mobile bearing knees (all of the low contact stress (LCS) design) and 17 fixed bearing knees (10 of the porous-coated anatomic (PCA) and 7 of the Miller/Galante design). Polyethylene particles were isolated from the tissue specimens and examined using both scanning electron microscopy and light-scattering analyses. The LCS mobile bearing knees produced smaller particulate debris (mean equivalent spherical diameter: 0.58 microm in LCS, 1.17 microm in PCA and 5.23 microm in M/G) and more granular debris (mean value: 93% in LCS, 77% in PCA and 15% in M/G).     

Pediatric Femoral Shaft Fracture: An Age-Based Treatment Algorithm

PurposeFractures of the femoral shaft in children are common. The rates of bone growth and remodeling in children vary according to their ages, which affect their respective management. MethodsThis paper evaluates the incidence and patterns of pediatric femoral shaft fracture and the current concepts of treatments available.ResultsThe type of fracture—closed or open; stable or unstable—needs to be taken into account. Child abuse should be suspected in fractures sustained by infants. For younger children, non-surgical management is preferred, which include Pavlik harness (< 6 months old) and early spica casting (6 months to 6 years old). Older children (> 6 years old) usually benefit from surgical treatments as outcomes of non-surgical alternatives are worse and are associated with prolonged recovery times. These operative measures for older children that are 6–12 years old include elastic stable intramedullary nailing and submuscular plating. Factors to be considered when devising an appropriate intervention include body mass, location of injury, and nature of fracture. For adolescent and skeletally mature teenagers (> 12 years old), rigid antegrade entry intramedullary fixation is indicated. In the event of open fractures or polytrauma, external fixation should be considered as a temporary treatment method for initial fracture stabilization.ConclusionAn age-based and evidence-based algorithm has been proposed to guide surgeons in the process of evaluating an appropriate treatment.     

Treatment of intracranial gliomas with bone marrow-derived dendritic cells pulsed with tumor antigens.

OBJECT: An approach toward the treatment of intracranial gliomas was developed in a rat experimental model. The authors investigated the ability of "professional" antigen-presenting cells (dendritic cells) to enhance host antitumor immune responses when injected as a vaccine into tumor-bearing animals. METHODS: Dendritic cells, the most potent antigen-presenting cells in the body, were isolated from rat bone marrow precursors stimulated in vitro with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4. Cultured cell populations were confirmed to be functional antigen-presenting cells on the basis of expressed major histocompatibility molecules, as analyzed by fluorescence-activated cell sorter cytofluorography. These dendritic cells were then pulsed (cocultured) ex vivo with acid-eluted tumor antigens from 9L glioma cells. Thirty-eight adult female Fischer 344 rats harboring 7-day-old intracranial 9L tumors were treated with three weekly subcutaneous injections of either control media (10 animals), unpulsed dendritic cells (six animals), dendritic cells pulsed with peptides extracted from normal rat astrocytes (10 animals), or 9L tumor antigen-pulsed dendritic cells (12 animals). The animals were followed for survival. At necropsy, the rat brains were removed and examined histologically, and spleens were harvested for cell-mediated cytotoxicity assays. The results indicate that tumor peptide-pulsed dendritic cell therapy led to prolonged survival in rats with established intracranial 9L tumors implanted 7 days prior to the initiation of vaccine therapy in vivo. Immunohistochemical analyses were used to document a significantly increased perilesional and intratumoral infiltration of CD8+ and CD4+ T cells in the groups treated with tumor antigen-pulsed dendritic cells compared with the control groups. In addition, the results of in vitro cytotoxicity assays suggest that vaccination with these peptide-pulsed dendritic cells can induce specific cytotoxic T lymphocytes against 9L tumor cells. CONCLUSIONS: Based on these results, dendritic antigen-presenting cells pulsed with acid-eluted peptides derived from autologous tumors represent a promising approach to the immunotherapy of established intracranial gliomas. which may serve as a basis for designing clinical trials in patients with brain tumors.     

The clinical significance of venom detection in patients of cobra snakebite.

Cobra snakebites are one of the most frequent occurrences among the poisonous snakebites. The correlation between the serum concentrations of cobra venom in the victims with the severity of systemic and local symptoms after envenoming is still awaited for investigation. In this paper, we have developed an enzyme-linked immunosorbent assay (ELISA) to detect Taiwan cobra venom existed in the serum of the cobra snakebite victims. This established technique allowed us to detect as low as 1 ng/ml. Totally, 31 serum samples of 27 recognized and suspected cobra snakebite patients were analyzed by the developed ELISA technique. The highest venom level detected was 1270 ng/ml in a case 2 h after being envenomed. We found that the serum concentrations of the venom in the bitten patients were well correlated with the severity of local tissue destruction. Venom levels might remain high 48 h after snakebite. Two or more vials of specific antivenom administered soon after snakebite were effective in neutralizing the circulating venom as revealed by ELISA. Higher doses of antivenom may be indicated in cases of cobra venom-induced local tissue destruction. In conclusion, these results indicate that venom detection in snakebite victims is valuable in diagnosis and severity assessment of Taiwan cobra snakebite.     

Assessing quality of a worksite health promotion programme from participants’ views: findings from a qualitative study in Malaysia

Background An assessment of the process and outcomes of a health promotion programme is necessary for the continuous improvement of a programme. Objective To explore the participants’ perceptions of the quality and effectiveness of the ‘Love Your Heart Programme’. Design A qualitative study using semi‐structured interviews with a purposive sample of participants of the ‘Love Your Heart’ programme. Interviews were based on an interview guide that grouped questions into four main subgroups: structure, process, immediate outcomes and impact. The interviews were audio‐recorded, transcribed verbatim and analysed using the principles of grounded theory. Results A total of 17 interviews were conducted. The participants were satisfied with the structural aspects of the programme. Different opinions arose regarding the ideal frequency and duration of the programme. The content of the seminars was thought to be too general. There was also a lack of interest in the ‘Road to a Healthy Heart’ booklet. All of the respondents had positive opinions about the communication skills and attitude of the health educator. The potential advantages and disadvantages of participating in the programme were discussed. Finally, the respondents expressed their satisfaction with the programme and the impact it had on them. Discussion and conclusions In general, the participants who were interviewed held the programme, and the health educator conducted the programme in high regard. The suggestions that were received can be used to further improve the acceptability and feasibility of the programme.     

Pharmacokinetic and pharmacodynamic comparison of conventional and controlled release formulations of motoprolol in healthy chinese subjects

Summary A double-blind, crossover comparison of the pharmacokinetics and pharmacodynamics of controlled- release metoprolol (CR) 100 mg and 200 mg, metoprolol plain tablet 100 mg, metoprolol Durules 200 mg, and placebo was carried out in 10 healthy Chinese subjects. Standardized treadmill exercise tests according to the Bruce protocol were performed at a steady state of medication, before and 2, 6, 12 and 24 hours after the dose, and multiple blood samples were collected for determination of the metoprolol concentration. The plasma metoprolol levels over 24 hours were more uniform after metoprolol CR than Durules and the plain tablet. The mean peak concentrations for CR 100 mg, 200 mg, Durules, and the plain tablets were 231, 426, 790, and 1105 nmol/l, respectively. The corresponding fluctuation incides were 1.1, 1.5, 2.2, and 5.0. The effects on exercise heart rate (EHR) were investigated at steady state. Metoprolol CR produced more even reduction in EHR over 24 hours than Durules and plain tablets. All four treatments gave similar maximal reduction in EHR of about 20% at 2 hours after the dose. In conclusion, once daily metoprolol CR showed almost even blood levels and provided relatively constant levels of beta¹ blockade over 24 hours in healthy Chinese subjects.