Arc-driven mGRASP highlights CA1 to CA3 synaptic engrams

Subpopulations of neurons display increased activity during memory encoding and manipulating the activity of these neurons can induce artificial formation or erasure of memories. Thus, these neurons are thought to be cellular engrams. Moreover, correlated activity between pre- and postsynaptic engram neurons is thought to lead to strengthening of their synaptic connections, thus increasing the probability of neural activity patterns occurring during encoding to reoccur at recall. Therefore, synapses between engram neurons can also be considered as a substrate of memory, or a synaptic engram. One can label synaptic engrams by targeting two complementary, non-fluorescent, synapse-targeted GFP fragments separately to the pre- and postsynaptic compartment of engram neurons; the two GFP fragments reconstitute a fluorescent GFP at the synaptic cleft between the engram neurons, thereby highlighting synaptic engrams. In this work we explored a transsynaptic GFP reconstitution system (mGRASP) to label synaptic engrams between hippocampal CA1 and CA3 engram neurons identified by different Immediate-Early Genes: cFos and Arc. We characterized the expression of the cellular and synaptic labels of the mGRASP system upon exposure to a novel environment or learning of a hippocampal-dependent memory task. We found that mGRASP under the control of transgenic ArcCre^ERT2 labeled synaptic engrams more efficiently than when controlled by viral cFostTA, possibly due to differences in the genetic systems rather than the specific IEG promoters.

Alzheimer's Prevention Education: If We Build It, Will They Come? www.AlzU.org

BACKGROUND

Internet-based educational interventions may be useful for impacting knowledge and behavioral change. However, in AD prevention, little data exists about which educational tools work best in terms of learning and interest in participating in clinical trials.

OBJECTIVES

Primary: Assess effectiveness of interactive webinars vs. written blog-posts on AD prevention learning. Secondary: Evaluate the effect of AD prevention education on interest in participating in clinical trials; Assess usability of, and user perceptions about, an online AD education research platform; Classify target populations (demographics, learning needs, interests).

DESIGN

Observational.

SETTING

Online.

PARTICIPANTS

Men/Women, aged 25+, recruited via facebook.com.

INTERVENTION

Alzheimer's Universe (www.AlzU.org) education research platform.

MEASUREMENTS

Pre/post-test performance, self-reported Likert-scale ratings, completion rates.

RESULTS

Over two-weeks, 4268 visits were generated. 503 signed-up for a user account (11.8% join rate), 196 participated in the lessons (39.0%) and 100 completed all beta-testing steps (19.9%). Users randomized to webinar instruction about AD prevention and the stages of AD demonstrated significant increases (p=0.01) in pre vs. post-testing scores compared to blog-post intervention. Upon joining, 42% were interested in participating in a clinical trial in AD prevention. After completing all beta-test activities, interest increased to 86%. Users were primarily women and the largest category was children of AD patients. 66.3% joined to learn more about AD prevention, 65.3% to learn more about AD treatment.

CONCLUSIONS

Webinar-based education led to significant improvements in learning about AD prevention and the stages of AD. AlzU.org participation more than doubled interest in AD prevention clinical trial participation. Subjects were quickly and cost-effectively recruited, and highly satisfied with the AD education research platform. Based on these data, we will further refine AlzU.org prior to public launch and aim to study the effectiveness of 25 interactive webinar-based vs. blog-post style lessons on learning and patient outcomes, in a randomized, within-subjects design trial.

Reduction of contact sensitivity responses to FITC, but not DNFB in mice lacking the tyrosine kinase, Itk (B103)

Itk (inducible T cell kinase) is a member of the Tec kinase family of nonreceptor protein tyrosine kinases that are expressed in T cells, NK cells, and mast cells. Defects in Itk protein lead to impaired T cell activation and effector function. Although mice lacking Itk are impaired in their ability to generate protective Th1 and Th2 responses in vivo, LCMV clearance requiring CD8+ T cells appear to be intact. Contact sensitivity (CS) is a type IV hypersensitivity reaction resulting from secondary skin exposure to a reactive hapten. Murine models of CS using chemical haptens such as DNFB are shown to be predominantly CD8+ T cell mediated with CD4+ T cells acting as modulators. Recently, data from CS models using FITC suggest a dominant role of Th2-type CD4+ T cells. The purpose of our studies was to determine whether Itk plays a role in the development of contact sensitivity responses to FITC or DNFB using Itk knockout mice. Indeed mice lacking Itk have significantly reduced ear swelling and leukocyte infiltration following FITC ear challenge compared to WT mice, which correlates with the lack of FITC-specific cytokine secretion from primed Itk KO LNC in vitro. In contrast, Itk−/− mice were able to generate ear swelling responses comparable to WT mice following DNFB challenge. Together, these data further support the effector role of CD4+ T cells in FITC-CS and the inability of Itk−/− mice to generate effective Th2 responses in vivo.

Experimental autoimmune encephalomyelitis induction in peptidylarginine deiminase 2 knockout mice

During the development of multiple sclerosis the destruction of the myelin sheath surrounding the neurites is accompanied by citrullination of several central nervous system (CNS) proteins, including myelin basic protein and glial fibrillary acidic protein. In experimental autoimmune encephalomyelitis (EAE), a disease induced in animals by immunization with proteins or peptides from the CNS, the animals develop symptoms similar to multiple sclerosis (MS). The increased levels of citrullinated CNS proteins associated with MS are also observed during the development of EAE. To study the role of CNS protein citrullination in EAE development, we induced EAE with a peptide derived from myelin oligodendrocyte glycoprotein (MOG(35-55)) in mice lacking the peptidylarginine deiminase 2 (PAD2) protein, because this enzyme was the most likely candidate to be involved in catalyzing CNS protein citrullination in the diseased state. Even though the PAD2 knockout mice displayed a dramatic reduction in the amount of citrullination present in the CNS, indicating that PAD2 is indeed responsible for the majority of detectable citrullination observed in EAE, the development of EAE was not impaired by genetic deletion of PAD2, suggesting that PAD2 catalyzed citrullination is not essential to the development of EAE.

Development and validation of a novel technique for murine first-pass radionuclide angiography with a fast multiwire camera and tantalum 178

BACKGROUND

The use of genetically altered mice as a model system to study cardiovascular disease has created a need for accurate and quantitative assessment of murine ventricular function. To address this very challenging problem, we have developed a technique of murine first-pass radionuclide angiography using pinhole imaging and the short-lived isotope tantalum 178 (Ta-178) with a high-speed multiwire proportional camera (MPC). METHODS AND RESULTS. An MPC was fitted with a pinhole lens of 2-mm-diameter aperture positioned 15 cm from the camera face. The short-lived isotope Ta-178 (half-life 9.3 minutes) was generated from the tungsten 178 (W-178) (half-life 21.7 days)/Ta-178 generator and concentrated on site to an injection volume of 15 to 20 microL. Mice were imaged in the supine position with the chest wall 3 mm from the camera pinhole aperture, and images were acquired at 160 frames per second after a rapid bolus injection of Ta-178. In the absence of a true gold standard, the technology was validated with measurements in control mice and mice with surgically ligated left anterior descending arteries (LADs). In addition, the effects of pharmacologic intervention with verapamil and with dobutamine were observed. Finally, peak aortic velocity measurements obtained with this technology were compared with those obtained with echocardiographic Doppler ultrasonography, the only available quantitative comparator. There was a significant decrease in the mean left ventricular ejection fraction (LVEF) between normal mice (62% +/- 4.6% [mean +/- SEM], n = 12) and mice with experimentally induced myocardial infarction produced by surgical LAD ligation (22% +/- 2.0%, n = 41; P <.01). The LVEF decreased from 51% +/- 5.8% to 37% +/- 3.5% in a group of normal mice receiving verapamil (P <.05, n = 8) and increased from 34% +/- 2.2% to 43% +/- 2.3% in a group of LAD-ligated mice receiving dobutamine (P <.01, n = 48). Peak camera sensitivity during first pass was 25,000 cps/mCi injected. Intraobserver and interobserver variability of LVEF was studied, yielding r = 0.9639 and 0.9529 and SE of the estimate 2.6% and 3.1%, respectively. Reproducibility in serial studies was excellent (r = 0.92, SE of the estimate 5.18).

CONCLUSIONS

This study demonstrates the development and use of a promising new method that uses the short-lived radioisotope Ta-178 and MPC for noninvasive quantification of murine ventricular function, that produces accurate and highly reproducible results, and that can be applied in multiple serial studies.

Reduction of antigen-induced airway hyperreactivity and eosinophilia in ICAM-1-deficient mice

A murine model of asthma is described in which we examined the role of intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of airway reactivity, pulmonary eosinophilia, and inflammation. We sensitized wild-type control [C57BL/6J, (+/+)] and ICAM-1 knockout [C57BL/6J-ICAM-1, (-/-)] mice to ovalbumin (OVA), and challenged them with OVA delivered by aerosol (OVA-OVA) to induce a phenotype consistent with an asthmatic response. Bronchial responsiveness to methacholine and counts of cell numbers and measurements of eosinophil content and cytokine levels in bronchoalveolar lavage fluid (BALF) were significantly attenuated in ICAM-1(-/-) mice as compared with (+/+) mice. We also showed that the absence of ICAM-1 had no significant affects on the production of serum IgE antibody, but did have an effect on ex vivo lymphocyte proliferation. Additionally, immunohistochemistry: (1) revealed increased staining for vascular cell adhesion molecule-1 (VCAM-1) after antigen challenge in the ICAM-1(-/-) mice but not in the ICAM-1(+/+) controls; and (2) confirmed the presence of alternatively spliced forms of ICAM-1 in the lungs of ICAM-1(-/-) mice. Thus, despite the availability of alternate adhesion pathways in ICAM-1(-/-) mice, the absence of ICAM-1 prevented eosinophils from entering the airways. In summary, we found that the ICAM-1 knockout mice exhibited a significantly inhibited response to aerosol antigen challenge for most of the parameters examined, and conclude that ICAM-1 is an important ligand mediating T-cell proliferation in response to antigen, eosinophil migration into the airways, and the development of airway hyperreactivity (AHR) in allergen-sensitized and -challenged mice.

Teacher assessments of children's behavioral disorders: demographic correlates

The relationship of demographic variables to teacher reports of behavior problems in six-to-eight-year-olds was examined. Contrary to previous research findings associating teacher-reported problems, with poverty and gender, multivariate analyses found significant associations only for ethnicity and caretakers' marital status. Implications for research on the impact of demographic factors on children's behavior problems and school performance are discussed.

The effect of menstruation on the pulmonary carbon monoxide diffusing capacity

We studied variations in DLCO during the menstrual cycle in 14 healthy women with a mean age of 29 (SD, 7) yr. Eight were using oral contraceptives, and six were not. DLCO was determined 1 to 7 d before the onset of menses, daily during each of the first 4 d of menses, and 5 to 10 d after onset of menses. In both groups of subjects, the highest values for DLCO were obtained before menses, the lowest were on the third day of menses, whereas after completion of menses the values increased but were not as high as prior to menses. The mean DLCO for all subjects was 23.1 (SD, 3.2) ml/min/mm Hg before menses, 20.9 (SD, 3.0) on the third day of menstruation, and 21.6 (SD, 3.3) 5 to 10 d after onset of menses. The mean percent difference between DLCO before and on the third day of menses in all 14 subjects was 9.2 (SD, 4.4) %. There were no significant changes in hemoglobin on these days to account for the changes in DLCO. Pulmonary capillary blood volume determined in 10 of the subjects did not show a significant change. It is concluded that DLCO can vary significantly during the menstrual cycle, with the highest values occurring prior to menses and the lowest values occurring on the third day of menses, with a mean difference between them of 9%. These variations need to be considered when evaluating DLCO in female patients in the menstrual age group.

Intercellular adhesion molecule-1 contributes to pulmonary oxygen toxicity in mice: role of leukocytes revised

In immature or injured lungs, impaired alveolar gas exchange forces the use of elevated levels of inhaled oxygen to maintain life. But, at high concentrations oxygen induces lung injury, edema, and bronchopulmonary dysplasia, probably by stimulating the generation of reactive oxygen radicals and subsequent neutrophil infiltration. In addition to regulating neutrophil diapedesis, intercellular adhesion molecule-1 (ICAM-1) expression is marked on inflamed alveolar epithelium, suggesting a role for ICAM-1 in oxygen-induced, neutrophil-mediated parenchymal damage. To test this, we evaluated the rat anti-mouse ICAM-1 monoclonal antibody YN1/1.7 in 2 protocols of oxygen-induced toxicity in adult, male Balb-c mice: greater than or equal to 95% O2 for 84 hr and greater than or equal to 95% O2 for 60 hr followed by 48 hr at 21% (ambient) O2. YN1/1.7 treatment partially attenuated the neutrophil infiltration, lung damage (lavage lactate dehydrogenase [LDH] activity) and dysfunction (reductions in respiratory system compliance [Crs] and diffusion capacity of the lungs for carbon monoxide [DLCO] in the 84 hr exposure protocol. In the milder 60 hr exposure protocol, YN1/1.7 completely blocked the oxygen-induced lung dysfunction (reductions in Crs and DLco). These results confirm the contribution of leukocytes in the pathogenesis of pulmonary oxygen toxicity and indicate that antagonism of ICAM-1 may provide a therapeutic approach to reducing hyperoxic lung injury and dysfunction.

Endothelial leukocyte adhesion molecule-1 mediates antigen-induced acute airway inflammation and late-phase airway obstruction in monkeys

This study examines the role of endothelial leukocyte adhesion molecule-1 (ELAM-1) in the development of the acute airway inflammation (cell influx) and late-phase airway obstruction in a primate model of extrinsic asthma. In animals sensitive to antigen, a single inhalation exposure induced the rapid expression of ELAM-1 (6 h) exclusively on vascular endothelium that correlated with the influx of neutrophils into the lungs and the onset of late-phase airway obstruction. In contrast, basal levels of ICAM-1 was constitutively expressed on vascular endothelium and airway epithelium before antigen challenge. After the single antigen exposure, changes in ICAM-1 expression did not correlate with neutrophil influx or the change in airway caliber. This was confirmed by showing that pretreatment with a monoclonal antibody to ICAM-1 did not inhibit the acute influx of neutrophils associated with late-phase airway obstruction, whereas a monoclonal antibody to ELAM-1 blocked both the influx of neutrophils and the late-phase airway obstruction. This study demonstrates a functional role for ELAM-1 in the development of acute airway inflammation in vivo. We conclude that, in primates, the late-phase response is the result of an ELAM-1 dependent influx of neutrophils. Therefore, the regulation of ELAM-1 expression may provide a novel approach to controlling the acute inflammatory response, and thereby, affecting airway function associated with inflammatory disorders, including asthma.

Distribution of ICAM-1 within decidua and placenta and its gestational age-associated changes

Intercellular adhesion molecule 1 (ICAM-1), a ligand of leukocyte function associated antigen 1 (LFA-1), is present on many cells, including monocyte/macrophages. ICAM-1 is considered to play an important role in the induction and maintenance of inflammatory responses by permitting leukocyte adhesion. Its expression is inducible on endothelial and epithelial cells exposed to various inflammatory cytokines (preceding expression of HLA-DR) and is maturation dependent in certain cell lines. The distribution of ICAM-1 in decidua and placenta was evaluated using peroxidase-antiperoxidase immunohistochemistry. In decidua of first and third trimesters, scattered ICAM-1-staining cells were observed. In placentas of first and third trimesters, all types of trophoblasts stained negatively for ICAM-1. Prior to 10 weeks of gestation, the villous stroma was uniformly ICAM-1 and HLA-DR unreactive. Beginning in the chorionic plate at approximately 10 weeks, scattered ICAM-1-positive stromal cells were observed, whereas stromal cells of the terminal villi revealed no ICAM-1. By 14-16 weeks, approximately 40-50% of the terminal villous stromal cells were ICAM-1 staining. This parallels the 40-50% of the villous stromal cells that share other immunohistochemical markers, such as EB-11, with monocyte/macrophages. The lack of functional maturation of the villous stromal macrophage may explain the rarity of chronic villitis early in gestation.

Discharging ICU ventilator-dependent patients to home healthcare

Patients who are ventilator dependent have few alternatives to continued hospitalization. Within our institution and community, intensive care unit (ICU) bed occupancy and lack of skilled nursing facilities forced us to look for other ways to meet their healthcare needs. The only placement alternative to continued hospitalization for some patients appeared to be home care, because it was available and cost-effective. The possibility of using home care for the ventilator-dependent patient was a new concept for many of the staff, and generated a moderate degree of anxiety among them. Overcoming the anxiety and developing and implementing the discharge plan became our goals. The goals were achieved when the patient was effectively and safely discharged from the ICU to his home.

Discharging ICU ventilator-dependent patients to home healthcare

Patients who are ventilator dependent have few alternatives to continued hospitalization. Within our institution and community, intensive care unit (ICU) bed occupancy and lack of skilled nursing facilities forced us to look for other ways to meet their healthcare needs. The only placement alternative to continued hospitalization for some patients appeared to be home care, because it was available and cost-effective. The possibility of using home care for the ventilator-dependent patient was a new concept for many of the staff, and generated a moderate degree of anxiety among them. Overcoming the anxiety and developing and implementing the discharge plan became our goals. The goals were achieved when the patient was effectively and safely discharged from the ICU to his home.

Intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of asthma

Airway eosinophilia, epithelial desquamation, and hyperresponsiveness are characteristics of the airway inflammation underlying bronchial asthma. The contribution of intercellular adhesion molecule-1 (ICAM-1) to eosinophil migration and airway responsiveness was studied. ICAM-1 partially mediated eosinophil adhesion to to endothelium in vitro and was upregulated on inflamed bronchial endothelium in vivo. ICAM-1 expression was also upregulated on inflamed airway epithelium in vitro and in vivo. In a primate model of asthma, a monoclonal antibody to ICAM-1 attenuated airway eosinophilia and hyperresponsiveness. Thus, antagonism of ICAM-1 may provide a therapeutic approach to reducing airway inflammation, hyperresponsiveness, and asthma symptoms.