Place conditioning in humans: opportunities for translational research

Rationale Translational research, especially research that bridges studies with humans and nonhuman species, is critical to advancing our understanding of human disorders such as addiction. This advancement requires reliable and rigorous models to study the underlying constructs contributing to the maladaptive behavior. Objective In this commentary, we address some of the challenges of conducting translational research by examining a single procedure, place conditioning. Place conditioning is commonly used with laboratory animals to study the conditioned rewarding effects of drugs, and recent studies indicate that a similar procedure can be used in humans. Results We discuss the opportunities and challenges of making the procedure comparable across species, as well as discuss the benefits of more systematically applying the procedure to humans. Conclusion We argue that the capacity of humans to report verbally on their internal experiences (perceptions, affective states, likes and dislikes) add an important dimension to the understanding of the procedures used in laboratory animals

The Statistics of Supersonic Isothermal Turbulence

We present results of large-scale three-dimensional simulations of supersonic Euler turbulence with the piecewise parabolic method and multiple grid resolutions up to 2048^3 points. Our numerical experiments describe non-magnetized driven turbulent flows with an isothermal equation of state and an rms Mach number of 6. We discuss numerical resolution issues and demonstrate convergence, in a statistical sense, of the inertial range dynamics in simulations on grids larger than 512^3 points. The simulations allowed us to measure the absolute velocity scaling exponents for the first time. The inertial range velocity scaling in this strongly compressible regime deviates substantially from the incompressible Kolmogorov laws. The slope of the velocity power spectrum, for instance, is -1.95 compared to -5/3 in the incompressible case. The exponent of the third-order velocity structure function is 1.28, while in incompressible turbulence it is known to be unity. We propose a natural extension of Kolmogorov's phenomenology that takes into account compressibility by mixing the velocity and density statistics and preserves the Kolmogorov scaling of the power spectrum and structure functions of the density-weighted velocity v=\rho^{1/3}u. The low-order statistics of v appear to be invariant with respect to changes in the Mach number. For instance, at Mach 6 the slope of the power spectrum of v is -1.69, and the exponent of the third-order structure function of v is unity. We also directly measure the mass dimension of the "fractal" density distribution in the inertial subrange, D_m = 2.4, which is similar to the observed fractal dimension of molecular clouds and agrees well with the cascade phenomenology.Comment: 15 pages, 19 figures, ApJ v665, n2, 200

An Unusual Case of Hemosiderotic Fibrohistiocytic Lipomatous Lesion: Correlation of MRI and Pathologic Findings

The spectrum of lipomatous lesions ranges from benign to highly malignant disease. Differentiation between these lesions is important to indicate prognosis and choose the most appropriate treatment. Hemosiderotic fibrohistiocytic lipomatous lesion (HFLL) is a rare subtype of lipomatous tumor. The diagnosis is usually based on clinical, histological, and immunohistochemical information. Where magnetic resonance (MR) imaging is a suitable modality to assess fatty tumors, no data is reported on MR imaging of HFLL. Here, the MR characteristics are described in correlation with pathologic findings in a case of HFLL in the left thigh, an unusual location

Reaching truckers in Brazil with non-stigmatizing and effective HIV/STI services

Research with mobile populations has demonstrated that men in the mobile workforce tend to be exposed to greater HIV risk, and have higher sexually transmitted infection (STI) and HIV prevalence, than those in less mobile or non-mobile professions. At the request of the Brazilian Ministry of Health and with support from USAID/Brazil, the Population Council conducted an assessment in Brazilian border areas to determine which populations were most in need of HIV prevention activities. The research revealed the presence of an extremely mobile, international truck driver community with little to no access to HIV prevention, testing, and treatment services. The intervention strategy of placing a health unit inside the customs station and offering HIV/STI-related services with other services to meet the general health needs of truckers was successful for reaching truckers, was acceptable and well received, and promoted some important HIV-related behavior change

Increasing risk behaviour can outweigh the benefits of antiretroviral drug treatment on the HIV incidence among men-having-sex-with-men in Amsterdam

Background: The transmission through contacts among MSM (men who have sex with men) is one of the dominating contributors to HIV prevalence in industrialized countries. In Amsterdam, the capital of the Netherlands, the MSM risk group has been traced for decades. This has motivated studies which provide detailed information about MSM's risk behavior statistically, psychologically and sociologically. Despite the era of potent antiretroviral therapy, the incidence of HIV among MSM increases. In the long term the contradictory effects of risk behavior and effective therapy are still poorly understood.Methods: Using a previously presented Complex Agent Network model, we describe steady and casual partnerships to predict the HIV spreading among MSM. Behavior-related parameters and values, inferred from studies on Amsterdam MSM, are fed into the model; we validate the model using historical yearly incidence data. Subsequently, we study scenarios to assess the contradictory effects of risk behavior and effective therapy, by varying corresponding values of parameters. Finally, we conduct quantitative analysis based on the resulting incidence data.R

Chlamydia pneumoniae aggravates vein graft intimal hyperplasia in a rat model

<p>Abstract</p> <p>Background</p> <p>Along with angioplasty, autologus vein grafts are commonly used for artery bypass grafting in patients with advanced arterial stenosis and drug-resistant angina pectoris. Although initially a successful procedure, long-term functionality is limited due to proliferation and migration of smooth muscle cells. Like in atherosclerosis, common chronic infections caused by viruses and bacteria may contribute to this process of vein graft failure. Here we investigated the possible role of <it>Chlamydia pneumoniae </it>(<it>Cpn</it>) in the pathogenesis of venous graft failure in an experimental animal model. In 2 groups (n = 10 rats/group), an epigastric vein-to-common femoral artery interposition graft was placed. Immediately thereafter, rats were infected with <it>Cpn </it>(5*10⁸IFU) or injected with control solutions. Rats were sacrificed three weeks after surgery and the grafts were harvested for morphometrical and immunohistochemical analysis.</p> <p>Results</p> <p><it>Cpn </it>administration immediately after vein grafting resulted in a significant increase in medial cross-sectional area, wall thickness and total wall area. There were no significant differences in T-cell or macrophage influx. Likewise, although positive immunostaining for both HSP60 and CRP could be detected, no differences were found between groups. Based on the observation that the number of cells/μm²was also not altered, we conclude that Cpn infection stimulates smooth muscle cell proliferation by hereunto unknown molecular mechanisms, resulting in a significant increase in intimal hyperplasia.</p> <p>Conclusion</p> <p>In conclusion, in a well defined animal model we present here for the first time evidence for a role of <it>Chlamydia pneumoniae </it>in the process of venous graft failure.</p

Automatic generation of absolute myocardial blood flow images using [15O]H2O and a clinical PET/CT scanner

PURPOSE: Parametric imaging of absolute myocardial blood flow (MBF) using [(15)O]H(2)O enables determination of MBF with high spatial resolution. The aim of this study was to develop a method for generating reproducible, high-quality and quantitative parametric MBF images with minimal user intervention. METHODS: Nineteen patients referred for evaluation of MBF underwent rest and adenosine stress [(15)O]H(2)O positron emission tomography (PET) scans. Ascending aorta and right ventricular (RV) cavity volumes of interest (VOIs) were used as input functions. Implementation of a basis function method (BFM) of the single-tissue model with an additional correction for RV spillover was used to generate parametric images. The average segmental MBF derived from parametric images was compared with MBF obtained using nonlinear least-squares regression (NLR) of VOI data. Four segmentation algorithms were evaluated for automatic extraction of input functions. Segmental MBF obtained using these input functions was compared with MBF obtained using manually defined input functions. RESULTS: The average parametric MBF showed a high agreement with NLR-derived MBF [intraclass correlation coefficient (ICC) = 0.984]. For each segmentation algorithm there was at least one implementation that yielded high agreement (ICC > 0.9) with manually obtained input functions, although MBF calculated using each algorithm was at least 10% higher. Cluster analysis with six clusters yielded the highest agreement (ICC = 0.977), together with good segmentation reproducibility (coefficient of variation of MBF <5%). CONCLUSION: Parametric MBF images of diagnostic quality can be generated automatically using cluster analysis and a implementation of a BFM of the single-tissue model with additional RV spillover correction. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00259-011-1730-3) contains supplementary material, which is available to authorized users

Anterior Cervical Infection: Presentation and Incidence of an Uncommon Postoperative Complication.

STUDY DESIGN: Retrospective multi-institutional case series. OBJECTIVE: The anterior cervical discectomy and fusion (ACDF) affords the surgeon the flexibility to treat a variety of cervical pathologies, with the majority being for degenerative and traumatic indications. Limited data in the literature describe the presentation and true incidence of postoperative surgical site infections. METHODS: A retrospective multicenter case series study was conducted involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network, selected for their excellence in spine care and clinical research infrastructure and experience. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, inclusive, were reviewed to identify the occurrence of 21 predefined treatment complications. Patients who underwent an ACDF were identified in the database and reviewed for the occurrence of postoperative anterior cervical infections. RESULTS: A total of 8887 patients were identified from a retrospective database analysis of 21 centers providing data for postoperative anterior cervical infections (17/21, 81% response rate). A total of 6 postoperative infections after ACDF were identified for a mean rate of 0.07% (range 0% to 0.39%). The mean age of patients identified was 57.5 (SD = 11.6, 66.7% female). The mean body mass index was 22.02. Of the total infections, half were smokers (n = 3). Two patients presented with myelopathy, and 3 patients presented with radiculopathic-type complaints. The mean length of stay was 4.7 days. All patients were treated aggressively with surgery for management of this complication, with improvement in all patients. There were no mortalities. CONCLUSION: The incidence of postoperative infection in ACDF is exceedingly low. The management has historically been urgent irrigation and debridement of the surgical site. However, due to the rarity of this occurrence, guidance for management is limited to retrospective series