Extensile triradiate approach for complex acetabular reconstruction in total hip arthroplasty

The triradiate approach as described by Mears has been used for open reduction of complex dual-column acetabular fractures. Mears extended the anterior limb of this incision to the symphysis pubis by the ilioinguinal approach. From a consecutive series of 43 total hip revisions, this approach was used successfully in seven cases in which extensile exposure was necessary to revise complicated acetabular reconstructions for arthroplasty. The approach was used also to perform complex acetabular reconstruction after en bloc tumor resection. Three patients had severe intrapelvic component protrusio and anterior column deficiency where close proximity of the prosthesis and femoral neurovascular bundle were detected before surgery. Massive allograft and pelvic reconstructions were used to span large anterior column defects and to stabilize pelvic dehiscence. Complications included one hip dislocation and one posterior flap tip necrosis. Follow-up ranged from six to 34 months. No graft failure has been noted.     

Anxiogenic-like consequences in animal models of complex partial seizures

Extracellular adenosine triphosphate (ATP) plays an important role in the regulation of endothelial function. However, its receptors and their signal-transduction pathways in major cerebral arterial endothelial cells are largely unknown. This study was undertaken functionally to classify the P2 purinoceptors in cultured bovine middle cerebral artery endothelial cells by using [Ca2+]i microfluorimetry. The rank order of potency to increase [Ca2+]i was 2-methylthio-ATP approximately ATP approximately uridine triphosphate (UTP) > adenosine diphosphate (ADP) > adenosine monophosphate (AMP) > alpha,beta-methylene-ATP > adenosine, suggesting that the effect was mediated by both P2y and P2u receptors. ATP, 2-methylthio-ATP, and UTP mobilized Ca2+ from intracellular stores and triggered Ca2+ entry. The effects of ATP, 2-methylthio-ATP, and UTP were reduced by phospholipase C inhibitor 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (NCDC), but only the effects of ATP and UTP were attenuated by pertussis toxin, indicating that P2y and P2u receptors may activate the same effector mechanisms by coupling to different G proteins. The [Ca2+]i entry caused by UTP was significantly reduced by the receptor-regulated Ca2+ channel blocker SK&F 96365, by P-450 inhibitor econazole and by inorganic Ca2+ entry blocker lanthanum. P2-receptor antagonists suramin, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), and reactive blue 2 reduced the effects of ATP and 2-methylthio-ATP, but not those of UTP, in a concentration-dependent manner. These studies suggest a coexistence of P2y and P2u receptors in cultured bovine middle cerebral artery endothelial cells.     

Use of personality assessment instruments in empirically guided treatment planning.

Treatment planning and monitoring are essential components of mental health service delivery in the era of managed care. Personality assessment instruments have long been used by practitioners to assist in psychodiagnosis and the identification of treatment needs and goals. Nevertheless, managed-care companies and 3rd-party payers are reluctant to authorize psychological assessment service and, instead, prefer that clinicians base their plans on clinical interviews. Research is reviewed documenting the utility of personality assessment instruments in empirically guided treatment planning and the superiority of this method over clinical interviewing. A new psychological test designed specifically for use in treatment planning, the Butcher Treatment Planning Inventory (J. N. Butcher, in press), is introduced and described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controversies in acetabular fractures

Open reduction and internal fixation has become the standard of care for the treatment of most displaced acetabular fractures. As surgical techniques have become refined, long term results of surgical fixation have improved. During the past 10 to 15 years, several controversies have surfaced in the orthopaedic literature regarding the treatment of acetabular fractures. The recent literature regarding acetabular fixation was reviewed. Controversies include the most efficacious surgical approach for complex acetabular fractures; the effectiveness of intraoperative sciatic nerve monitoring; the most effective method of prophylaxis against deep vein thrombosis; and the indications for and method of prophylaxis against heterotopic bone formation.     

Energy-selective reconstructions in X-ray computerized tomography

All X-ray computerized tomography systems that are available or proposed base their reconstructions on measurements that integrate over energy. X-ray tubes produce a broad spectrum of photon energies and a great deal of information can be derived by measuring changes in the transmitted spectrum. We show that for any material, complete energy spectral information may be summarized by a few constants which are independent of energy. A technique is presented which uses simple, low-resolution, energy spectrum measurements and conventional computerized tomography techniques to calculate these constants at every point within a cross-section of an object. For comparable accuracy, patient dose is shown to be approximately the same as that produced by conventional systems. Possible uses of energy spectral information for diagnosis are presented.     

Errors in measurement of acetabular index

The usefulness of the fPSA fraction in the differential diagnosis of benign prostate hyperplasia (BPH) and prostate cancer was evaluated, with the aim of improving the diagnostic efficacy of PSA. Serum PSA and fPSA determinations were performed by an enzymoimmunoassay technique on an ES-300 system. fPSA constitutes a minor fraction both in normal subjects and in patients with prostate disease, being significantly lower in patients with untreated prostate cancer than in patients with BPH. Likewise, the authors have observed that the sensitivity of the fPSA/PSA ratio has an inversely proportional relationship with the stage of the disease. The results obtained in patients with PSA levels between 4 and 20 micrograms/l are also of note. In this series of patients, the efficacy of the fPSA/PSA ratio was higher than that of PSA, showing a sensitivity of 44% and a specificity of 95% at the cut-off of 0.08.     

Use of latent variable models for detecting discrimination in salaries.

A major criticism of the direct regression approach to detecting employment discrimination has been that when qualifications are not perfectly measured, one could be misled by the well-known bias associated with using fallible covariates with nonequivalent groups—sometimes called the "errors in variables" problem. With regard to salary discrimination, a number of solutions to this "problem" have been proposed. I argue that this bias should be treated as irrelevant and that the proposed solutions are misleading. In order to sustain the argument against direct regression (or its nonparametric analogue), one must be willing to assume that true quality of performance influences salary over and above the influence of measures of performance. This involves postulating a latent variable, often labeled "qualifications," that has a direct effect on salary. For several reasons it may be undesirable to make this assumption. Other problems with the regression approach, however, do require serious consideration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of multiple urolume endourethral prostheses in complex bulbar urethral strictures

PURPOSE: We evaluated patients who received multiple UroLume Wallstents during the North American UroLume trial for the treatment of recurrent bulbar urethral strictures. MATERIALS AND METHODS: A total of 41 patients received multiple UroLume stents. The clinical histories and therapeutic outcomes of these patients were reviewed. RESULTS: Of the patients 23% required placement of multiple urethral stents. Stents placed at the initial procedure were required for strictures longer than 2.5 cm. and for multiple, separate strictures. Indications for secondary insertion included recurrent stricture adjacent to the stent, hyperplastic tissue growth within the stent and gaps between previously adjacent stents. The repeat treatment rate was 43.9% versus 14.3% for the study group overall. Urine flow rates and symptom scores in the multiple stent group showed improvement similar to that of the study group overall. CONCLUSIONS: Patients who required multiple stents had greater rates of repeat treatment but similarly improved urine flows and symptom scores, which were maintained at 2 years.     

Use of disease models in the development and evaluation of therapeutic agents

A key part of the regulatory review of new therapeutic agents depends on a clear demonstration of their efficacy. There can be difficulties when the evaluations of efficacy depend only on in vitro studies, such as minimum inhibitory concentrations (MICs), and clinical field trials. The MIC data often correlate poorly with in vivo results, and field trials can suffer from the unpredictability of disease outbreaks and from differences in the severity of outbreaks at different sites. This paper discusses the use of experimentally induced diseases as a means of bridging the gap between the in vitro data and the results of field trials.     

Three-dimensional reconstructions from cryoelectron microscopy images reveal an intimate complex between helicase DnaB and its loading partner DnaC

Progress has recently been made in the understanding of the function of the cytochrome bc1 complex and related proteins in the context of recent structural information. The structures support many features that were predicted from sequence analysis and biophysical studies, but contain some surprises. Most dramatically, it is apparent that the iron-sulfur protein can take up different positions in different crystals, suggesting a novel mechanism for electron transfer through domain movement. Evidence from studies of mutant strains, in which the function of the sites or the binding of inhibitors is perturbed, has provided clues about the mechanism.     

Wear in retrieved Charnley acetabular sockets

One hundred and twenty-nine Charnley acetabular components were acquired at the time of revision surgery and a tribological investigation undertaken. The relative occurrence of pitting in the unworn and worn regions of the sockets suggest that most of the cement ingress occurs during the early part of the service life. The penetration depth of the explanted sockets was determined using the shadowgraph technique. Observation of the profiles in the wear planes suggest that, in general, the creep component was not a significant proportion of the overall change in the inner bore of the socket. Using weighted ordinary least squares regression, in which the intercept was not assumed to be zero, mean penetration and wear volume rates of 0.02 (SE = 0.02) mm/year and 55 (SE = 5) mm3/year, respectively, were recorded and are in agreement with other retrieval studies. In neither case was the intercept found to be significantly different from zero. A mean clinical wear factor, Kclinical, equal to 2.1 (SE = 0.2) x 10(-6) mm3/N m was calculated which is considerably larger than that found in laboratory experiments which purport to reflect in vivo conditions. In this analysis, a significant positive intercept was observed [96 (SE = 36) mm3] and may be evidence of the small initial penetration due to creep reported in simulator experiments. A strong positive association between kclinical and the arithmetical mean roughness, Ra, of the femoral head was also demonstrated although the rate of change was not as great as that cited for laboratory experiments.     

Use of prosthesis-generated computed tomographic information for diagnostic and surgical treatment planning

Diagnosis, treatment planning, and prediction of a final implant-supported prosthetic outcome require precise noninvasive presurgical information. By combining the use of a clinically verified barium-coated template and interactive computed tomography (SIM/Plant, Columbia Scientific, Inc., Columbia, Maryland), the implant team can determine and address the relevant issues affecting treatment outcomes. Those issues include: implant-prosthesis incompatibility, recognition of anatomic limitations and anomalies, the need for presurgical bone augmentation, implant diameter and distribution, abutment type and angle, bone density, soft tissue augmentation requirements, accurate fee determination, and medicolegal protection. The data collection methodology and format for the Mecall and Rosenfeld prosthesis prediction analysis are discussed as part of case presentation.