PubMed Health⌕ Search

Biomedical subjects

B E Earp

Publications and source records attributed to B E Earp.

3 recordsLinked to original sources

Augmented amputations of the lower extremity.

Ten patients who had amputations of a lower extremity for high-grade sarcomas underwent bone augmentation with either allograft or autograft between 1988 and 1996. There were eight transfemoral amputations and two transtibial amputations. The transferred segments consisted of one proximal tibia and six distal tibia autografts, two allografts, one autograft talar dome and first metatarsal, and one with a patellar cap of a supracondylar amputation. The average length of followup was 54 months. There were no nonunions of any of the grafts. There were three wound problems requiring additional operations. One autograft resorbed, and one autograft had a late infection. There was one local recurrence. Augmentation to provide length resulted in a 42% increase in bone length in those performed purely for length. All patients were able to use standard prostheses. Functional outcome was appropriate to the amputation level. Half of the patients avoided more proximal levels of amputation because of the ability to augment the osteotomy. The use of nonvascularized structural autografts or allografts is a simple procedure that can produce a superior residual limb in patients undergoing amputation. Its use should be considered in patients for whom traditional amputation techniques will result in poor function, difficulty in fitting a prosthesis, or greater than necessary anatomic loss.

Adolescent↗

Sequence variation as a strategy for crystallizing RNA motifs.

The determination of RNA structures by X-ray crystallography is an exciting and developing field. At present, the crystallographic characterization of RNA is limited by the difficulty in obtaining large, high quality crystals. This paper outlines several techniques for improving the likelihood of obtaining RNA crystals, for improving the size of those crystals, and for extending the limit of the diffraction maxima. Sequence variations have proven to be more effective in changing the quality of the crystals than variations in crystallization conditions, often making the difference between obtaining true single crystals and multiply twinned crystalline material.

Base Sequence↗

HPLC purification of RNA for crystallography and NMR.

Homogeneous preparations of milligram quantities of RNA are a prerequisite for their characterization by biophysical methods such as crystallography or NMR spectroscopy. Methods for obtaining milligram quantities of pure synthetic RNA are described in this paper. These methods employ anion exchange HPLC for purifying full-length sequence from failure sequences and incompletely deprotected material. RNA molecules with little or extensive amounts of secondary structure could be purified. In cases where the RNA molecule was tightly folded, the cation in the eluent buffer influenced both the distinction of the peaks during chromatography and the final folded conformation. Finally, two RNA sequences were chemically synthesized, deprotected, purified, and crystallized using this methodology.

Base Sequence↗