Tissue-Specific Ferritin- and GFP-Based Genetic Vectors Visualize Neurons by MRI in the Intact and Post-Ischemic Rat Brain

(1) Background: Neurogenesis is considered to be a potential brain repair mechanism and is enhanced in stroke. It is difficult to reconstruct the neurogenesis process only from the histological sections taken from different animals at different stages of brain damage and restoration. Study of neurogenesis would greatly benefit from development of tissue-specific visualization probes. (2) Purpose: The study aimed to explore if overexpression of ferritin, a nontoxic iron-binding protein, under a doublecortin promoter can be used for non-invasive visualization of neurogenesis using magnetic resonance imaging (MRI). (3) Methods: Ferritin heavy chain (FerrH) was expressed in the adeno-associated viral backbone (AAV) under the doublecortin promoter (pDCX), specific for young neurons, in the viral construct AAV-pDCX-FerrH. Expression of the enhanced green fluorescent protein (eGFP) was used as an expression control (AAV-pDCX-eGFP). The viral vectors or phosphate-buffered saline (PBS) were injected intracerebrally into 18 adult male Sprague–Dawley rats. Three days before injection, rats underwent transient middle-cerebral-artery occlusion or sham operation. Animals were subjected to In vivo MRI study before surgery and on days 7, 14, 21, and 28 days after injection using a Bruker BioSpec 11.7 T scanner. Brain sections obtained on day 28 after injection were immunostained for ferritin, young (DCX) and mature (NeuN) neurons, and activated microglia/macrophages (CD68). Additionally, RT-PCR was performed to confirm ferritin expression. (4) Results: T2* images in post-ischemic brains of animals injected with AAV-pDCX-FerrH showed two distinct zones of MRI signal hypointensity in the ipsilesioned hemisphere starting from 14 days after viral injection—in the ischemic lesion and near the lateral ventricle and subventricular zone (SVZ). In sham-operated animals, only one zone of hypointensity near the lateral ventricle and SVZ was revealed. Immunochemistry showed that ferritin-expressing cells in ischemic lesions were macrophages (88.1%), while ferritin-expressing cells near the lateral ventricle in animals both after ischemia and sham operation were mostly mature (55.7% and 61.8%, respectively) and young (30.6% and 7.1%, respectively) neurons. RT-PCR confirmed upregulated expression of ferritin in the caudoputamen and corpus callosum. Surprisingly, in animals injected with AAV-pDCX-eGFP we similarly observed two zones of hypointensity on T2* images. Cellular studies also showed the presence of mature (81.5%) and young neurons (6.1%) near the lateral ventricle in both postischemic and sham-operated animals, while macrophages in ischemic lesions were ferritin-positive (98.2%). (5) Conclusion: Ferritin overexpression induced by injection of AAV-pDCX-FerrH was detected by MRI using T2*-weighted images, which was confirmed by immunochemistry showing ferritin in young and mature neurons. Expression of eGFP also caused a comparable reduced MR signal intensity in T2*-weighted images. Additional studies are needed to investigate the potential and tissue-specific features of the use of eGFP and ferritin expression in MRI studies.     

Caregiver Resentment: Explaining Why Care Recipients Exhibit Problem Behavior.

Objective: To determine how attributions caregivers make about the source of problem behavior of frail, older care recipients may contribute to caregiver resentment of care recipients and obligations associated with providing care. Design: Cross-sectional interview data, screened according to primary cause of need for care. Participants: 103 caregiver-care recipient dyads in which care recipient was cognitively impaired (CI; n = 72) or physically disabled without cognitive impairment (n = 31). Outcome Measure: 17-item Caregiver Resentment Scale. Results: Caregivers of CI elders reported providing more care in response to CI-related care recipient disturbing behavior. However, beyond the source of impairment, disturbing (externally attributable) behavior typical of CI, and amount of care provided, resentment was predicted by controlling and manipulative (internally attributable) care recipient behavior. Conclusions: Caregivers are more resentful when care recipients are difficult in ways that they can attribute to the person rather than to the illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

COMPARE: a web accessible tool for investigating mechanisms of cell growth inhibition

For more than 10 years the National Cancer Institute (NCI) has tested compounds for their ability to inhibit the growth of human tumor cell lines in culture (NCI screen). Work of Ken Paull [J. Natl. Cancer Inst. 81 (1989) 1088] demonstrated that compounds with similar mechanism of cell growth inhibition show similar patterns of activity in the NCI screen. This observation was developed into an algorithm called COMPARE and has been successfully used to predict mechanisms for a wide variety of compounds. More recently, this method has been extended to associate patterns of cell growth inhibition by compounds with measurements of molecular entities (such as gene expression) in the cell lines in the NCI screen. The COMPARE method and associated data are freely available on the Developmental Therapeutics Program (DTP) web site (http://dtp.nci.nih.gov/). Examples of the use of COMPARE on these web pages will be explained and demonstrated. Published by Elsevier Science Inc.     

Relationships between job difficulty, employee's attitude toward his job, and supervisory ratings of the employee effectiveness.

Using correlational techniques, an investigation was made of the relationships between job difficulty (estimated by job evaluation factors), employee attitudes toward his job, and job environment, and supervisory ratings of employee performance. As job difficulty increased, employee attitudes were significantly more positive toward the job, management, and communication, and opportunity for advancement. Partial correlations showed that the relationship between job satisfaction and job difficulty increased when the effects of general morale were eliminated. Supervisory ratings of employee effectiveness were significantly rated (negatively) to employee salary and job tenure. Correlations between employee's attitude dimensions indicate increasing complexity of job content and increased content with people as a part of the job, are positively related to an employee's attitude toward his job. (PsycINFO Database Record (c) 2010 APA, all rights reserved)