Treatment of middle-third clavicle fractures using anterior plating with a dynamic compression plate (DCP).

Significantly displaced midshaft clavicle fractures can be managed operatively to restore anatomy and allow early mobilization. Several techniques have described using precontoured anatomically designed plates placed on the superior surface of the bone or reconstruction plates contoured by the surgeon placed either superiorly or anteriorly. We describe the use of the dynamic compression plate placed anteriorly on the clavicle in treating these fractures and discuss the relative advantages of this technique. We have a case series of 8 patients over a 2-year period, who were followed up and all went on to successful fracture union.

MR safety and compatibility of a noninvasively expandable total-joint endoprosthesis.

A noninvasively expandable total-joint endoprosthesis is now available for pediatric patients; the prosthesis can be lengthened by external application of a magnetic field. We investigated the risks of unintentional heating or lengthening of the prosthesis during MR imaging and evaluated the effect of the device on the diagnostic efficacy of MR imaging of surrounding tissues. We performed MR imaging at 1.5 T by using standard pulse sequences and pulse sequences with high-gradient and high-radiofrequency duty cycle. MR imaging caused no measurable change in prosthesis length, and the temperature of the prosthesis increased by less than 1 degrees C during repeated 14-min exposures. Despite significant signal loss and image distortion around the prosthetic joint, clinically useful images were obtained as close as 12 cm from the ends of the prosthetic stems, measured toward the body of the device. Thus, the prosthesis can be safely exposed to MR imaging pulse sequences at 1.5 T, and the visualization of some tissue surrounding the device is clinically useful.

Collagen gel systems for sustained delivery and tissue engineering.

Collagen gels are flowable, suggesting the possibility of an easily injectable, biocompatible drug delivery matrix. Sustained release of therapeutic molecules from collagen matrices, however, is beset with difficulties. Fibrillar collagen gels have an effective pore size of several tens of nanometers, too large to control release by hindered diffusion. To control release, it is necessary to rely on binding of the active agent to collagen, either by covalent or non-covalent bonds, or on sequestering in a secondary matrix. Such steps rapidly increase the complexity of the system. Non-fibrillar collagen has a lower effective pore size (4-6 nm), but it dissolves rapidly in vivo (approximately 24 h). For tissue engineering applications, collagen gels are more attractive, since they can act as a "cage" to retain cells or as gene delivery complexes, which are larger than drugs and therapeutic proteins. The gels have limitations in terms of strength, but reinforcement with solid components and alignment during gelation and culture can improve performance.

A case-control study of female-to-female nonintimate violence in an urban area.

OBJECTIVES: The aims of this study were to describe the characteristics surrounding female-to-female nonpartner violence and to identify independent factors associated with risk of female-to-female intentional injuries. METHODS: A case-control investigation was conducted among women who resided in an urban, low-income community and presented for emergency department care for injuries inflicted by female nonpartners. RESULTS: Women were typically victimized by women they knew (88%), in outdoor locations (60%), and in the presence of others (91%). Those found to be at risk for injury typically were young and socially active, used marijuana, and had experienced other kinds of violence. CONCLUSIONS: The present results showed that women injured by female nonpartners had limited resources, experienced disorder in their lives, and were the victims of violence within multiple relationships.

Characterization of the low-pH responses of Helicobacter pylori using genomic DNA arrays.

Helicobacter pylori is unique among bacterial pathogens in its ability to persist in the acidic environment of the human stomach. To identify H. pylori genes responsive to low pH, the authors assembled a high-density array of PCR-amplified random genomic DNA. Hybridization of radiolabelled cDNA probes, prepared using total RNA from bacteria exposed to buffer at either pH 4.0 or pH 7.0, allowed both qualitative and quantitative information on differential gene expression to be obtained. A previously described low-pH-induced gene, cagA, was identified together with several novel genes that may have relevance to the survival and persistence of H. pylori in the gastric environment. These include genes encoding enzymes involved in LPS and phospholipid synthesis and secF, encoding a component of the protein export machinery. A hypothetical protein unique to H. pylori (HP0681) was also found to be acid induced. Genes down-regulated at pH 4.0 include those encoding a sugar nucleotide biosynthesis protein, a flagellar protein and an outer-membrane protein. Differential gene expression was confirmed by total RNA slot-blot hybridization.