From 'D' to 'I': A critique of the current United States preventive services task force recommendation for testicular cancer screening.

In 2004, the United States Preventive Services Task Force (USPSTF) gave testicular cancer (TCa) screening a 'D' recommendation, discouraging the use of this preventive service. The USPSTF suggested that screening, inclusive of testicular self-examination (TSE) and clinician examination, does not reduce TCa mortality rates and that the high risk of false positives could serve as a detriment to patient quality of life. Others suggests that TCa screening is ineffective at detecting early-stage cases of TCa and readily highlights a lack of empirical evidence demonstrating said efficacy. These assertions, however, stand in stark contrast to the widely held support of TCa screening among practicing public health professionals, advocacy groups, and clinicians. In this present study, a review was conducted of the methods and processes used by the USPSTF in their 2011 reaffirmation of the 'D' grade recommendation. The evidence base and commentary offered as to why TSE, as part of the overall recommendation for TCa screening, was given a 'D' grade were analyzed for logical reasoning and methodological rigor. Considering the methodological flaws and the veritable lack of evidence needed to grant a conclusive recommendation, the question is raised if the current 'D' grade for TCa screening (i.e. discourage the use of said service) should be changed to an 'I' statement (i.e. the balance of benefits and harms is indeterminate). Therefore the purpose of this paper is to present the evidence of TCa screening in the context of efficacy and prevention in order for the field to reassess its relative value.

Geometric variations of acetabular component design and its effect on radiographic osseointegration.

The Reflection uncemented acetabular component (Smith & Nephew, Memphis, Tenn) for total hip arthroplasty is available in 2 geometric variants. The first has a completely hemispherical design; the second has a peripheral rim expansion designed to increase initial press fit and aid osseointegration. The clinical and radiologic outcomes of 527 consecutive primary total hip arthroplasties were reviewed to investigate the differences in component design. Of the components, 95.6% survived at 96 months with revision for aseptic loosening as the end point, with no significant difference between the 2 component designs. Eighty percent of hemispherical and 57% of peripherally expanded components were considered completely osseointegrated at final radiologic review. The midterm radiologic outcome of peripherally expanded acetabular components is inferior to that of a completely hemispherical design.

Computer navigation in the reduction and fixation of femoral shaft fractures: a randomized control study.

OBJECTIVES: We investigated the accuracy of reduction of intramedullary nailed femoral shaft fractures in human cadavers, comparing conventional and computer navigation techniques. METHODS: Twenty femoral shaft fractures were created in human cadavers, with segmental defects ranging from 9 to 53 mm in length (Winquist 3-4, AO 32C2). All fractures were fixed with antegrade 9 mm diameter femoral nails on a radiolucent operating table. Five fractures ("Fluoro" group) were fixed with conventional techniques and fifteen fractures ("Nav 1" and "Nav 2" groups) with computer navigation, using fluoroscopic images of the normal femur to correct for length and rotation. Postoperative CT scans compared femoral length and rotation with the normal leg. RESULTS: Mean leg length discrepancy in the computer navigation groups was smaller, namely, 3.6 mm for Nav 1 (95% CI: 1.072 to 6.128) and 4.2 mm for Nav 2 (95% CI: 0.63 to 7.75) vs. 9.8 mm for Fluoro (95% CI: 6.225 to 13.37) (p<0.023). Mean rotational discrepancies were 8.7° for Nav 1 (95% CI: 4.282 to 13.12) and 5.6° for Nav 2 (95% CI: -0.65 to 11.85) vs. 9.0° for Fluoro (95% CI: 2.752 to 15.25) (p=0.650). CONCLUSIONS: Computer navigation significantly improves the accuracy of femoral shaft fracture fixation with regard to leg length, but not rotational deformity.

Acute compartment syndrome of the thigh following minor trauma in a patient on dual anti-platelet therapy.

Acute compartment syndrome of the thigh is a rare surgical emergency. It is usually associated with high energy trauma and concomitant femoral fracture. We present the case of a 54 year old man who developed acute compartment syndrome of the thigh following a low energy traumatic hamstring tear. Background anti-platelet therapy and hospital prescribed anticoagulants were likely contributors to this pathology. We describe these factors and discuss the issues associated with assessment of minor trauma in the anti-coagulated patient.

The effect of cement gun and cement syringe use on the tibial cement mantle in total knee arthroplasty.

Evidence suggests that a thicker cement mantle improves fixation strength and resistance to tensile and shear forces in the tibial component of total knee arthroplasty. A low proportion of orthopaedic surgeons currently use techniques to improve cement penetration in the tibial plateau. We demonstrate that the use of a pressurized cement gun or cement syringe provides a highly statistically significant difference (P < .001) to the depth of the tibial cement mantle and reduction in radiolucent lines when compared to cement applied by hand. This ensures a thicker cement mantle and may reduce the possibility of early failure by improving the strength of fixation and the resistance to tensile and shear forces. There is no statistical difference in the cement mantle produced by the cement syringe and the cement gun.

PCR amplification of DNA containing non-standard base pairs by variants of reverse transcriptase from Human Immunodeficiency Virus-1.

As the next step towards generating a synthetic biology from artificial genetic information systems, we have examined variants of HIV reverse transcriptase (RT) for their ability to synthesize duplex DNA incorporating the non-standard base pair between 2,4-diaminopyrimidine (pyDAD), a pyrimidine presenting a hydrogen bond 'donor-acceptor-donor' pattern to the complementary base, and xanthine (puADA), a purine presenting a hydrogen bond 'acceptor-donor-acceptor' pattern. This base pair fits the Watson-Crick geometry, but is joined by a pattern of hydrogen bond donor and acceptor groups different from those joining the GC and AT pairs. A variant of HIV-RT where Tyr 188 is replaced by Leu, has emerged from experiments where HIV was challenged to grow in the presence of drugs targeted against the RT, such as L-697639, TIBO and nevirapine. These drugs bind at a site near, but not in, the active site. This variant accepts the pyDAD-puADA base pair significantly better than wild type HIV-RT, and we used this as a starting point. A second mutation, E478Q, was introduced into the Y188L variant, in the event that the residual nuclease activity observed is due to the RT, and not a contaminant. The doubly mutated RT incorporated the non-standard pair with sufficient fidelity that the variant could be used to amplify oligonucleotides containing pyDAD and puADA through several rounds of a polymerase chain reaction (PCR) without losing the non-standard base pair. This is the first time where DNA containing non-standard base pairs with alternative hydrogen bonding patterns has been amplified by a full PCR. This work also illustrates a research strategy that combines in clinico pre-evolution of proteins followed by rational design to obtain an enzyme that meets a particular technological specification.