Mounting and calibration of stairs on piezoelectric force platforms

To calculate the centre of pressure using piezoelectric force plates mounted on pads, no net tensile stresses may be imposed on the surface of the plate. This condition is violated when stairs are attached to the plates, unless the plates are preloaded. Typical shear forces encountered when climbing stairs were used to determine required preloads of approximately 16.4 N/cm step height. Vertical and horizontal loads were applied at known locations on the steps, and points of application were calculated. Deviations were within ± 3 mm. The effect of point of application inaccuracy on calculated joint moments is considerable. A 2 cm medial shift in the point of application resulted in calculated peak knee abduction/adduction moment errors of 35%.     

Hepatocellular carcinoma: assessment of resectability by computed tomography and ultrasound

A retrospective review of the CT and ultrasound scans from examinations of 30 patients who had hepatocellular carcinoma (hepatoma) was undertaken with special emphasis placed on evaluation of hepatic distribution of tumor, vascular invasion, and extrahepatic spread. Although both CT and ultrasound detected hepatoma in 29 of 30 patients (96%), CT showed more extensive hepatic parenchymal involvement in eight of the patients. Vascular invasion was seen more frequently with ultrasound than with CT. Invasion into the main portal vein was seen by ultrasound in 11 of 30 patients (37%). Extrahepatic spread of tumor was much more frequently detected by CT and was present in 21 of 30 patients (70%). A reasoned approach to the diagnostic workup of hepatomas that will minimize invasive procedures and unnecessary surgery is presented.     

Self-limiting extravasation in the unused urinary bladder

Patients being evaluated as potential renal transplant recipients routinely undergo voiding cystourethrography. Eight patients were encountered in whom extraperitoneal extravasation was noted from the region of the ureterovesical junction during voiding (seven patients) or during filling (one patient). Extravasation was bilateral in six patients and unilateral in two. The patients neither experienced symptoms related to the extravasation, required treatment, nor had sequelae. Five of the eight patients have subsequently received renal transplants and their bladders were observed to be normal at surgery. Cystoscopy was also performed in two of these five patients and was unremarkable. After transplantation, these patients' bladders functioned normally and gave rise to no symptoms.     

Prostaglandin E2 inhibits its own renal transport by downregulation of organic anion transporters rOAT1 and rOAT3

Prostaglandin E2 (PGE2) is the principal mediator of fever and inflammation. Recently, evidence emerged that during febrile response, PGE2 that is generated in the periphery enters the hypothalamus and contributes to the maintenance of fever. In a rat model of fever generation, peripheral PGE2 is increased, whereas clearance by metabolism of peripheral PGE2 is downregulated. The major route of PGE2 excretion is via the renal proximal tubular organic anion secretory system, where basolateral uptake that is mediated by renal organic anion transporter 1 (rOAT1) and rOAT3 is rate limiting. Therefore, it was hypothesized that PGE2 itself will abolish its excretion by rOAT1 or rOAT3. Fluorescein was used as a prototypic organic anion, and NRK-52E cells from rat served as a proximal tubular model system. PGE2 time-dependently downregulates basolateral organic anion uptake, without affecting cell volume or cell protein, recirculation of counter ions, or proximal tubular transport systems in general. In addition, PGE2 diminishes expression of both rOAT1 and rOAT3. Both organic anion uptake and expression of rOAT1 and rOAT3 are dose-dependently downregulated by PGE2. These findings suggest that during fever or inflammation, renal secretory transport of PGE2 is reduced, contributing to elevated PGE2 levels in blood. These data fit into the hypothetical concept of peripheral PGE2's playing a significant role in fever. The described regulatory mechanism may also be of relevance in chronic inflammatory events. Moreover, the data presented could explain why increased plasma urate levels occur in diseases that go along with increased levels of PGE2.     

Epidemiologic background and long-term course of disease in human immunodeficiency virus type 1-infected blood donors identified before routine laboratory screening. Transfusion Safety Study Group

BACKGROUND: The long-term course of human immunodeficiency virus type 1 (HIV-1)-related disease among seropositive blood donors has not been described. The enrollment and epidemiologic background of HIV-1- infected donors in the Transfusion Safety Study and their immunologic and clinical progression are described. STUDY DESIGN AND METHODS: Through the testing of approximately 200,000 sera from donations made in late 1984 and early 1985, 146 anti-HIV-1-positive donors and 151 uninfected matched donors were enrolled. These two cohorts were followed with 6-month interval histories and laboratory testing. RESULTS: Seropositive donors detected before the institution of routine anti-HIV-1 screening disproportionately were first-time donors and men with exclusively male sexual contacts. The actuarial probability of a person's developing AIDS within 7 years after donation was 40 percent; the probability of a person's dying of AIDS was 28 percent. AIDS developed more often when the donor was p24 antigen-positive at donation. Over a 3-year period, significant decreases occurred in CD4+, CD2+CD26+, CD4+CD29+, and CD20+CD21+ counts, but not in CD8+ subsets, CD20+, or CD14+. CONCLUSION: The high proportions of first-time donations and exclusively homosexual men among seropositive donors suggest that test-seeking may have contributed to the high HIV-1 prevalence in the repository. Implementation of alternative test sites when routine donor screening began in 1985 may have averted many high- risk donations. The disease course in HIV-1-infected donors had the same wide spectrum of immunologic and clinical manifestations as were reported for other cohorts.     

What do we know about how to do audit and feedback? Pitfalls in applying evidence from a systematic review

Background  

Improving the quality of health care requires a range of evidence-based activities. Audit and feedback is commonly used as a quality improvement tool in the UK National Health Service [NHS]. We set out to assess whether current guidance and systematic review evidence can sufficiently inform practical decisions about how to use audit and feedback to improve quality of care.