The effects of metals on embryo-larval and adult life stages of the sea urchin, Diadema antillarum

Since the massive population decline of the long-spined sea urchin, Diadema antillarum, in the early 1980s, the dynamics of coral reef ecosystems in the Caribbean have changed tremendously. The absence of D. antillarum, once a keystone herbivore, has led to macroalgal dominance in many of these reef communities. D. antillarum is not only important ecologically, but may also be a sensitive bioindicator species for toxicant exposure. Echinoderm larval development tests were conducted with D. antillarum exposed to elevated levels of aqueous copper (Cu), silver (Ag), nickel (Ni), or selenium (Se). All metals significantly affected larval development, based on normal development to the pluteus stage. The EC50s based on dissolved metal concentrations were 11 microg/L Cu, 6 microg/L Ag, 15 microg/L Ni, and 26 microg/L Se. Adult sea urchins were exposed to aqueous copper under flow through conditions for 96 h. The 96-h LC50 for this exposure was 25 microg/L dissolved Cu. Additionally, behavioral and physiological disturbance was observed. The physiological responses included both acid-base balance disturbance, as evidenced by reduced coelomic fluid pH and apparent ionoregulatory effects. In addition, behavioral effects included spatial orientation within the exposure tank, spine closure, and loss of spines. The high sensitivity of both adult and larval D. antillarum to these metals supports the use of this organism as an important biological indicator for metal exposure in marine environments.     

Hinged elbow external fixators: indications and uses

Hinged external fixation of the elbow joint can play an important role in managing complicated fracture-dislocations, joint instability after extensive contracture release, and distraction interposition arthroplasty. Application of these devices requires accurate alignment of the fixator axis with the anatomic axis of the elbow. The primary therapeutic goal is to allow joint motion while protecting the healing ligaments. Common complications include pin loosening, injury to adjacent neurovascular structures, cellulitis, and loss of reduction. Although reported data are limited, this technique is a useful adjunct in patients with complex elbow instability.     

Distal radius fracture fixation with an intramedullary nail

The purpose of this article is to describe a novel technique and implant system for fixation of unstable (Arbeitsgemeinschat fur Osteosynthesesfragen Types A and B) distal radius fractures. Currently the most common complications directly related to distal radius plate fixation includes tenosynovitis, tendon attrition, and rupture, often necessitating hardware removal. With the advent of this new device, a decrease in soft tissue complication is expected. The implant utilizes the principles of load sharing, subchondral screw divergence, and locked fixed-angle fixation. It is inserted through a small skin incision at the radial styloid and does not further devascularize the fracture fragments. The limited surgical dissection and rigid fracture fixation allow for minimal postoperative immobilization and an early return of function. The authors believe that this system is a valuable addition to the arsenal of distal radius fracture treatment options and can quickly get patients back on the road of recovery.     

Managing hematologic toxicities

This overview of the hematologic toxicities of cancer chemotherapy addresses the frequency and clinical significance of neutropenia, anemia, and thrombocytopenia and attempts to provide evidence-based guidelines, based on clinical trials, for the use of cytokine growth factors and transfusion support.The current emphasis on high-dose and dose-dense chemotherapy increases the need for close attention to the amelioration ofhematologic toxicities. The latter is highly dependent upon the appropriate and judicious use of cytokine support. Although these supportive agents may be relatively nontoxic, it is important to understand their potential side effects and to use them only when warranted by evidence-based studies.     

Yeast coexpression of human papillomavirus types 6 and 16 capsid proteins

The L1 and L2 capsid proteins of animal and human papillomaviruses (HPVs) can self-assemble into virus-like particles (VLPs) that closely resemble native virions. The use of different animal models shows that VLPs can be very efficient at inducing a protective immune response. However, studies with infectious HPV virions and VLPs of different HPV types indicate that the immune response is predominantly type-specific. We have generated a diploid yeast strain that coexpresses the L1 and L2 capsid proteins of both HPV-6b and HPV-16, and we have purified fully assembled VLPs banding in a cesium chloride gradient at the expected density of 1.29-1.3 mg/ml. Experimental evidence strongly indicated that the four proteins coassembled into VLPs. Western blot analysis, using anti-HPV-6 and anti-HPV-16 L1-specific monoclonal antibodies and type-specific L2 antisera, demonstrated that all four proteins copurified. Most importantly, immunoprecipitation experiments, carried out using type-specific anti-L1 monoclonals and either total yeast cell extracts or purified VLPs, confirmed the interaction and the formation of covalent disulfide bonds between the two L1 proteins. Finally, HPV-6/16 VLPs administered to mice induced conformational antibodies against both L1 protein types. These results suggest that coexpression of different capsid proteins may provide new tools for the induction of antibodies directed against multiple HPV types.     

Phagocytic function of monocytes in children with human immunodeficiency virus type 1 infection

We investigated the phagocytic function of monocytes in 7- to 10-year-old children horizontally infected with human immunodeficiency virus type 1 (HIV-1) in comparison to that in healthy sex- and age-matched controls. CR3-mediated phagocytosis was increased in patients with HIV-associated pulmonary tuberculosis, independently of CD4 counts and p24 antigenemia.