Sustained pressurization of polymethylmethacrylate: a comparison of low- and moderate-viscosity bone cements

There is at present great uncertainty relating to the fixation of joint implants. The deficiencies of acrylic bone cement are well documented, but the limitations of cementless fixation are as yet imcompletely identified. The purpose of this study was to investigate the potential of sustained external pressurization to improve the mechanical characteristics of conventional acrylic bone cement. The effect of serially increasing sustained pressurization of two commerically available acrylic bone cements (Simplex-P and LVC) was evaluated in human cadaver femora. A new method for determination of the shear strength of the bone-cement interface in place of the traditional pushout tests was used. In this model, there was a significant increase in the bone-cement interfacial shear strength with increasing pressure, but no difference in the shear strength was found between the two cements. At all pressure levels, the shear strength of the cement was greater than that previously reported. Increased cement penetration into the cortical bone was demonstrated with increasing pressure and low-viscosity cement, but the extent of cement penetration did not correlate with the shear strength of the bone-cement interface.     

Preceptorship programs: a public relations tool.

This article discusses the components and benefits of the public relations model, as developed by Black and Sharp (1983), and the use of this model in the development and implementation of a successful preceptorship program at Columbus College in Columbus, Georgia.     

Conducting a participatory community-based survey for a community health intervention on Detroit's east side.

This article describes a participatory action research process that brought together community members, representatives from community-based organizations and service providers, and academic researchers to collect, interpret, and apply community information to address issues related to the health of women and children in a geographically defined urban area. It describes the development and administration of a community-based survey designed to inform an intervention research project; discusses the establishment of a community/research partnership and issues that the partnership confronted in the process of developing and administering the survey; and examines the contributions of participants, and implications for research and collective action.     

The effect of stasis on a microvascular anastomosis

An experiment was done in rats to determine the effect of stopping the flow of blood across a fresh anastomosis. It was found that brief periods of stasis, up to 30 minutes, caused a minimal increase in the rate of thrombosis, but 60 minutes of stasis caused a significant risk of thrombosis in both arteries and veins. The thrombosis associated with stasis could be prevented by the systemic administration of heparin.     

Comparison of feticide carried out by cordocentesis versus cardiac puncture.

OBJECTIVE: Feticide may be achieved by the injection of strong potassium chloride (KCl) into the fetal circulation via the cardiac route, or less frequently, into the umbilical cord. Despite the relative frequency of this procedure, little published information is available on the subject. SUBJECTS AND METHODS: This was a retrospective analysis of all feticide procedures carried out prior to legal pregnancy termination in mid trimester of pregnancy from January 1996 to July 2001, in a tertiary fetal medicine referral center. The effect of gestational age and the route of access to fetal the circulation on the dose of strong KCl required to achieve cardiac asystole was evaluated. RESULTS: A total of 106 women underwent the procedure of feticide during the study period. Gestational age had no effect on the dose of strong KCl. The median dose of KCl administered by cordocentesis (5 mL) was significantly less (P < 0.001) than the dose required when fetal cardiocentesis was performed for administration of the drug (10 mL). CONCLUSION: This is the first comparative study of feticide by the administration of strong KCl by fetal cardiocentesis and cordocentesis. The study demonstrates that both cardiac and umbilical routes can be used to achieve feticide effectively, without compromising maternal safety. A finding of this study is that significantly smaller doses of KCl were required to achieve fetal cardiac asystole when using the umbilical compared to the cardiac route, although this may be explained by differences in technique. Strong 15% KCl can safely be used to achieve feticide in volumes up to 20 mL for cardiocentesis and 8 mL for cordocentesis.