Analysis of individual acidic organelles by capillary electrophoresis with laser-induced fluorescence detection facilitated by the endocytosis of fluorescently labeled microspheres

Submicrometer-sized fluorescent microspheres were loaded into the acidic organelles of NS-1 mouse myeloma cells via endocytosis. Confocal microscopy imaging showed that microspheres colocalized nearly perfectly with LysoTracker Red, a probe that stains acidic organelles. Unlike LysoTracker dyes that seem to leak from acidic organelles upon cell disruption, microspheres are retained within these organelles, facilitating their analysis following isolation. Using capillary electrophoresis (CE) with laser-induced fluorescence detection (LIF), the electrophoretic mobilities of acidic organelles were individually calculated and fluorescence intensities individually measured. When cells were incubated for sufficient time to allow for endocytosis (48 h) with 3.9 x 10(3) microspheres/cell, replicate CE-LIF analyses of the corresponding isolated fraction indicated a dramatic increase in the number of detected events (n = 1990 +/- 234) and in the overall fluorescence intensity of the individual events (0.38 +/- 0.01 RFU; average +/- SD; n = 3) over the corresponding <10-min incubations (n = 60; 0.21 RFU, respectively). In addition, a treatment with 4-fold increase in microsphere density (1.6 x 10(4) microspheres/cell), increased the number of detected individual events (n = 3427 +/- 101) and altered only slightly the fluorescence intensity and electrophoretic mobility distributions. The individual electrophoretic mobility values ranged from -1.45 x 10(-)(4) to -3.0 x 10(-)(4) cm(2) V(-)(1) s(-)(1) while the individual fluorescence values ranged from 0.1 V to over 8 V, demonstrating the benefit of detecting organelles individually rather than averaging their properties over single cells or bulk homogenates.     

Dynamic mechanical response of elastic spherical inclusions to impulsive acoustic radiation force excitation

Acoustic radiation force impulse imaging has been used clinically to study the dynamic response of lesions relative to their background material to focused, impulsive acoustic radiation force excitations through the generation of dynamic displacement field images. Dynamic displacement data are typically displayed as a set of parametric images, including displacement immediately after excitation, maximum displacement, time to peak displacement, and recovery time from peak displacement. To date, however, no definitive trends have been established between these parametric images and the tissues' mechanical properties. This work demonstrates that displacement magnitude, time to peak displacement, and recovery time are all inversely related to the Young's modulus in homogeneous elastic media. Experimentally, pulse repetition frequency during displacement tracking limits stiffness resolution using the time to peak displacement parameter. The excitation pulse duration also impacts the time to peak parameter, with longer pulses reducing the inertial effects present during impulsive excitations. Material density affects tissue dynamics, but is not expected to play a significant role in biological tissues. The presence of an elastic spherical inclusion in the imaged medium significantly alters the tissue dynamics in response to impulsive, focused acoustic radiation force excitations. Times to peak displacement for excitations within and outside an elastic inclusion are still indicative of local material stiffness; however, recovery times are altered due to the reflection and transmission of shear waves at the inclusion boundaries. These shear wave interactions cause stiffer inclusions to appear to be displaced longer than the more compliant background material. The magnitude of shear waves reflected at elastic lesion boundaries is dependent on the stiffness contrast between the inclusion and the background material, and the stiffness and size of the inclusion dictate when shear wave reflections within the lesion will interfere with one another. Jitter and bias associated with the ultrasonic displacement tracking also impact the estimation of a tissue's dynamic response to acoustic radiation force excitation.     

The Sustainability of an Entrepreneurial City?

The paper applies an urban political ecology approach to interrogating the use of sustainability constructs by key international governance agencies. We draw on political economy of urban sustainability to identify central themes in the reports to reveal limitations and contradictions in the deployment of the environmental sustainability construct. We argue that the Organisation of Economic Cooperation and Development and the World Bank offer little towards the development of a new vision for future cities, only affirmation of neoliberal urbanism. Promisingly, some of ‘key trends’ identified by UN-Habitat will enhance the democratic content of socio-environmental construction. This will achieve a more equitable distribution of social power and inclusive mode of environmental production.     

The response-class matrix: A procedure for recording parent-child interactions.

Describes a procedure for monitoring dyadic interactions which provides immediate information about behavior and its context, yet is easily implemented in a wide range of situations. 2 recorders make use of 2 specially designed matrices that together provide a 3-term contingency record and make it possible to look at dyadic social interaction patterns and obtain some estimate of both antecedent and consequent stimulus control. Resulting information can be used in planning treatment and evaluating outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mississippi Scale for Combat-Related Posttraumatic Stress Disorder: Three studies in reliability and validity.

The Mississippi Scale for Combat-Related Posttraumatic Stress Disorder is a 35-item self-report scale derived from Diagnostic and Statistical Manual of Mental Disorders (DSM-III) criteria for the disorder. This article describes a series of three studies designed to explore the psychometric properties of the scale. Study 1 used 362 Vietnam veterans seeking help at Vet Centers (Operation Outreach) to confirm the internal consistency of the instrument and provide an assessment of its factor structure. Study 2 demonstrated the high test–retest reliability of the instrument over a period of 1 week. Study 3 indicated that the test's sensitivity was .93, specificity was .89, and overall hit rate was .90 when it was used to differentiate between a posttraumatic stress disorder (PTSD) group and two non-PTSD comparison groups. The utility of the test when it is administered within the context of a multiaxial approach to assess military-related PTSD is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)