Motion at the modular acetabular shell and liner interface. A comparative study.

Excessive polyethylene debris generated from a total hip arthroplasty can lead to osteolysis and premature revision. Most of this polyethylene debris comes from the concave articulation. However, abrasive wear on the convex side of a modular polyethylene component also may play a role in this problem.

Sequence-specific Priming and Exonuclease-released Fluorescence Assay for Rapid and Reliable HLA-A Molecular Typing.

Background: The rapid and sensitive method described for low-resolution DNA typing of alleles at the HLA-A locus is based on a sequence-specific primer polymerase chain reaction approach that eliminates post-polymerase chain reaction gel electrophoresis to analyze the results. Methods and Results: This method takes advantage of the 5' --> 3' exonuclease activity of the Taq polymerase normally present during polymerase chain reaction. This sequence-specific priming and exonuclease-released fluorescence assay was conducted on 40 DNA samples derived from homozygous cell lines and peripheral blood lymphocytes that represented the majority of the HLA-A alleles.

Double-labeled fluorescent probes for 5' nuclease assays: purification and performance evaluation.

An inexpensive method for the purification and evaluation of user-synthesized or crude commercially prepared double-labeled fluorescent probes is presented. These probes exhibit the characteristics required for use in 5'-nuclease assays, including efficient reporter dye quenching, target specificity and susceptibility to cleavage by Taq DNA polymerase during PCR amplification. The method is suitable for research laboratories that wish to develop 5' nuclease assays for the detection of PCR-amplified target sequences to eliminate the requirement for agarose gels and to advance throughput.

Exonuclease-released Fluorescence Detection of Human Parvovirus B19 DNA.

Background: The 5;-->3;-exonuclease activity of Thermus aquaticus (Taq) DNA polymerase permits polymerase chain reaction (PCR) product detection immediately after amplification using a fluorogenic probe. This approach eliminates the requirement for gel electrophoresis or enzyme immunoassays (EIA). The ligonucleotide probe is labeled with a reporter dye at its 5' terminus and a quencher dye at its 3' terminus and is present during DNA amplification.

Sequence-specific priming and exonuclease-released fluorescence detection of HLA-DQB1 alleles.

Molecular typing of HLA DQB1 alleles, employing sequence-specific primers (SSP) for PCR amplification, was used to test a novel method that eliminates the requirement for subsequent gel electrophoresis or additional hybridization steps by directly detecting positive reactions. We have evaluated the performance of this fluorescence-based oligonucleotide probe assay to assign the most common DQB1 alleles on DNA from 14 homozygous cell lines and in a blind study of 50 diabetic patient samples that had been previously typed at the DQB1 locus using SSOP and conventional SSP-based approaches. We used a panel of 14 DQB1 SSP primer pairs, internal control primers, and a combination of 4 fluorescent oligonucleotide probes to detect 14 alleles or groups of alleles and controls.

Ischemic preconditioning reduces infarct size in swine myocardium.

We evaluated the hypothesis that stunning swine myocardium with brief ischemia reduces oxygen demand in the stunned region and increases tolerance of myocardium to longer periods of ischemia. Wall function was quantified with ultrasonic crystals aligned to measure wall thickening, and stunning was achieved with two cycles of left anterior descending coronary artery (LAD) occlusion (10 minutes) and reperfusion (30 minutes), after which the LAD was occluded for 60 minutes and reperfused for 90 minutes. Infarct size (as a percent of risk region) was then determined by incubating myocardium with para-nitro blue tetrazolium.