Conditioned Activity and Instrumental Reinforcement Following Long-Term Oral Consumption of Cocaine by Rats.

Food-reinforced conditioned activity and instrumental responding were measured in rats after 50 weeks of continuous access to a cocaine-saccharin solution in their home cages. The elevation of conditioned activity produced by acute access to the cocaine-saccharin solution in the home cage during testing was abolished by long-term preexposure to the cocaine solution, an effect that was reversed by systemic administration of cocaine immediately prior to testing. By contrast, chronic cocaine preexposure enhanced instrumental responding for both cocaine-sucrose and pure sucrose solutions. These results support the idea that long-term cocaine exposure enhances subsequent reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contact with out-group friends as a predictor of meta-attitudinal strength and accessibility of attitudes toward gay men.

Two studies examined the effects of cross-group friendships on heterosexuals' attitudes toward gay men. In Study 1, the authors tested the effects of cross-group friendships with gay men on out-group attitudes, meta-attitudinal strength, and attitude accessibility. The authors simultaneously explored mediational effects of intergroup anxiety. Path analysis showed that cross-group friendships were associated with meta-attitudinally stronger and more accessible out-group attitudes, and the effects on all 3 criterion variables were mediated by intergroup anxiety. In Study 2, the authors sought to replicate the basic results of Study 1, while additionally exploring mediational effects of closeness of cross-group friendship and moderational effects of perceived group typicality. Structural equation modeling showed that cross-group friendships were associated with meta-attitudinally stronger and more accessible out-group attitudes; friendships had indirect effects on all 3 criterion variables, via closeness of friendship and intergroup anxiety. Closeness of friendship only predicted lower intergroup anxiety, however, when the out-group friend was perceived as highly typical. The authors emphasize the importance of considering the nature of out-group attitudes more completely when evaluating the effectiveness of intergroup contact in reducing prejudice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of brain, body, and magnet bore temperatures on energy metabolism during global cerebral ischemia and reperfusion monitored by magnetic resonance spectroscopy in rats

To record brain temperature for comparison with rectal and temporalis muscle temperatures in preliminary studies before MR spectroscopy experiments, a thermistor was inserted into the basal ganglia in eight anesthetized, ventilated, and physiologically monitored rats. The rats were placed in an MR spectrometer and subjected to 60 min of global cerebral ischemia and 2 h of reperfusion without radiofrequency (RF) pulsing. Body temperature was maintained at 37.5-38.0 degrees C (normothermia) or 36.5-37.0 degrees C (mild hypothermia). Brain temperature during ischemia, which dropped to 31.9 +/- 0.3 (hypothermia) and 33.6 +/- 0.5 degrees C (normothermia), correlated with temporalis muscle temperature (r2 = 0.92) but not with body or magnet bore temperature measurements. Ischemia reduced brain temperature approximately 1.7 degrees C in rats subjected to mild hypothermia (1 degree reduction of body temperature). Parallel MR spectroscopy experiments showed no significant difference in energy metabolites between normothermic and hypothermic rats during ischemia. However, the metabolic recovery was more extensive 20-60 min after the onset of reperfusion in hypothermic rats, although not thereafter (P < 0.05). Mild hypothermia speeds metabolic recovery temporarily during reperfusion but does not retard energy failure during global ischemia in rats.     

Sensing methodology for in vivo stability evaluation of total hip and knee arthroplasty

This paper describes an implantable, remotely interrogated system for the in vivo measurement of both micromotion and migration in applications such as total hip arthroplasty (THA) and total knee arthroplasty (TKA). These metrics are the primary indicators of post-operative implant stability and their easy availability represents an important advance in the ability of clinicians to assess the long-term stability of the implants and also to plan and optimise patients’ rehabilitation protocols. The system is based on a modified form of differential variable reluctance transducer (DVRT) whose null-point is set automatically by means of a self-calibration algorithm. The self-calibration process not only allows the measuring bridge to work at maximum accuracy (i.e. for micromotion measurements) but also automatically records gross changes in position (migration). Simulations and preliminary measurements show that the calibration algorithm works correctly in spite of component tolerances and initial set up errors, and that the device can measure micromotion with an amplitude as low as 1 μm with a gross displacement (migration) in the range 0 to ±4 mm.     

Transfer Functions of the Slip-Controlled Induction Machine

The use of a feedback loop to regulate the slip frequency of an inverter-driven induction machine is viewed as replacing the normal independent control of stator frequency with independent control of slip frequency. For steady-state conditions the two modes of operation are shown to produce characteristics analogous to shunt and series dc machines. A method employing closed-form transfer functions, a reduced set of nondimensional parameters, and a general root locus diagram is used to present the dynamic characteristics of controlled slip frequency operation and to compare performance with conventional operation. The parameter range in the general diagram is sufficient to incorporate nearly all standard induction machines over a wide size and frequency range. The results demonstrate that the ratio K? of the rotor transient time constant to the static electromechanical time constant is a critical parameter in the comparison of the two modes. Since this parameter tends to increase with machine size, the relative advantages of slip frequency control are shown to be machine-size dependent. Inclusion of a speed-control loop regulating machine voltage is also Considered and shown to be described by the same general root loci. The performance of this closed-loop system is also shown to be very dependent on K? and hence on machine size.     

Interleukin-1 mediates a rapid inflammatory response after injection of adenoviral vectors into the brain

Adenovirus-mediated gene transfer into the brain is associated with significant inflammation and activation of anti-vector and anti-transgene immune responses that curtail the gene delivery of adenoviruses and therapeutic efficacy. Elucidating the molecular mediators of inflammatory and immune responses to adenoviruses injected into the brain should allow us to inhibit their inflammatory actions, thereby reducing vector clearance and enhance adenoviral-mediated gene transfer into the CNS. Cytokines are primary mediators of the immune response and are released during inflammation. Here we report for the first time that injection of replication-deficient adenovirus vectors into the cerebral ventricles of rats causes a rapid increase in body temperature. This fever response precedes any vector-encoded transgene expression and occurs with vectors encoding no transgene, as well as with vectors encoding a therapeutic transgene i.e., HSV1-thymidine kinase. No fever is detected after infection of the striatum, an important brain target in studies on neurodegeneration. After infection of the brain ventricles, CSF levels of immunoreactive tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta increase significantly (up to 300-fold). In the hypothalamus, the locus of thermoregulation in the brain, only IL-1beta and IL-6 are significantly elevated. A neutralizing TNF-alpha antibody has no effect on adenovirus-induced fever. However, pretreatment with either the IL-1 receptor antagonist or the cyclooxygenase inhibitor flurbiprofen completely abolishes adenovirus-induced fever, suggesting that IL-1 and prostaglandins are direct mediators of this response. These results are the first to demonstrate that IL-1, but not TNF-alpha, is the main mediator of a very early inflammatory response to adenovirus in the brain.     

Team cognition in group interventions: The relation between coleaders' shared mental models and group climate.

The relation between the convergence in group coleaders' mental models of their groups and group members' perceptions of group climate was examined. Coleaders of 8 intergroup dialogue groups provided paired-comparison ratings of the similarity of their group members, and group members provided group climate ratings, following each of 7 sessions. The paired-comparison ratings were analyzed using pathfinder network analysis (Schvaneveldt, 1990) to examine the structure of each coleader's mental model of her or his group, and to compare these mental models within coleader pairs to determine degree of similarity in coleaders' mental models for each coleader pair for each week (i.e., how similarly coleaders of a group view their group). Growth curve analyses of the degree of similarity and group climate data showed an increase in similarity of coleaders' mental models within groups across sessions, and that similarity in coleader mental models was related to increases in the engaged and decreases in the avoiding aspects of the group climate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical and functional interactions between the herpes simplex virus UL15 and UL28 DNA cleavage and packaging proteins

Herpes simplex virus (HSV) DNA is cleaved from concatemers and packaged into capsids in infected cell nuclei. This process requires seven viral proteins, including UL15 and UL28. UL15 expressed alone displays a nuclear localization, while UL28 remains cytoplasmic. Coexpression with UL15 enables UL28 to enter nuclei, suggesting an interaction between the two proteins. Additionally, UL28 copurified with UL15 from HSV-infected cells after ion-exchange and DNA affinity chromatography, and the complex sedimented as a 1:1 heterodimer upon sucrose gradient centrifugation. These findings are evidence of a physical interaction of UL15 and UL28 and a functional role for UL15 in directing UL28 to the nucleus.     

Progression detection of stage I nonseminomatous testis cancer on surveillance: implications for the followup protocol

PURPOSE: To optimize followup in patients with stage I nonseminomatous testis cancer on surveillance we evaluated the contribution of each followup modality to the detection of progression as well as morbidity and mortality outcomes. MATERIALS AND METHODS: After orchiectomy 170 patients with clinical stage I nonseminoma were prospectively placed on a surveillance protocol. History, physical examination, serum tumor markers, abdominal and pelvic computerized tomography (CT), and chest x-ray were used for followup. The number of failures, methods and timing of progression detection, treatments required, mortality rate and subsequent contralateral primary tumors were recorded. RESULTS: The 170 surveillance patients were followed a median of 6.3 years. Within 2 years (median 6.9 months) postoperatively 48 patients (28.2%) had disease progression. History, physical examination, markers, CT and chest radiography provided the initial evidence of progression in 18 (37.5%), 34 (70.8%), 34 (70.8%), and 4 (8.3%) patients, respectively. Each modality was the only indicator of failure in 2 (4.2%), 4 (8.3%), 10 (20.8%) and 0 cases, respectively. Of the 170 patients 122 (71.8%) required no additional treatment beyond orchiectomy, 26 (15.3%) received 1 and 22 (12.9%) underwent more than 1 therapeutic modality. Only 1 patient (0.6%) died of disease. Contralateral tumors developed in 5 cases (2.9%) therapeutic a mean of 8.1 years after orchiectomy. CONCLUSIONS: In stage I nonseminoma patients, surveillance history, physical examination, tumor markers and abdominopelvic CT are necessary components of the followup protocol. Removal of routine chest x-ray from the protocol would not have changed progression detection. The initial surveillance visit must occur by 2 months postoperatively. Patients should be followed beyond 5 years and likely for life in addition to regular patient self-examination.