Diphteria Research Today is a free monthly online journal that collates and summarizes the latest research about Diphteria, including details on infection, immunization, vaccines, symptoms.

Posttraining ablation of adult-generated neurons degrades previously acquired memories.

Arruda-Carvalho M, Sakaguchi M, Akers KG, Josselyn SA, Frankland PW

Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada M5G 1X8, Department of Physiology, University of Toronto, Toronto, Canada M5S 1A8, and Institute of Medical Science, University of Toronto, Toronto, Canada M5S 1A8.

New neurons are continuously generated in the subgranular zone of the adult hippocampus and, once sufficiently mature, are thought to integrate into hippocampal memory circuits. However, whether they play an essential role in subsequent memory expression is not known. Previous studies have shown that suppression of adult neurogenesis often (but not always) impairs subsequent hippocampus-dependent learning (i.e., produces anterograde effects). A major challenge for these studies is that these new neurons represent only a small subpopulation of all dentate granule cells, and so there is large potential for either partial or complete compensation by granule cells generated earlier on during development. A potentially more powerful approach to investigate this question would be to ablate adult-generated neurons after they have already become part of a memory trace (i.e., retrograde effects). Here we developed a diphtheria toxin-based strategy in mice that allowed us to selectively ablate a population of predominantly mature, adult-generated neurons either before or after learning, without affecting ongoing neurogenesis. Removal of these neurons before learning did not prevent the formation of new contextual fear or water maze memories. In contrast, removal of an equivalent population after learning degraded existing contextual fear and water maze memories, without affecting nonhippocampal memory. Ablation of these adult-generated neurons even 1 month after learning produced equivalent memory degradation in the water maze. These retrograde effects suggest that adult-generated neurons form a critical and enduring component of hippocampal memory traces.

Published 21 October 2011 in J Neurosci, 31(42): 15113-27.
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Articles on Diphteria published 21 October 2011:

An olfactory circuit increases the fidelity of visual behavior.   J Neurosci, 31(42): 15035-47.

Multimodal integration allows neural circuits to be activated in a behaviorally context-specific manner. In the case of odor plume tracking by Drosophila, an attractive odorant increases the influence of yaw-optic flow on steering behavior in flight, which enhances visual stability reflexes, resulting in straighter flight trajectories within an odor plume. However, it is not well understood whether context-specific changes in optomotor behavior are the result of an increased sensitivity to ... [Abstract] [Full-text]

Vaccination coverage among adolescents and risk factors associated with incomplete immunization.   Eur J Pediatr, 170(11): 1419-26.

The compliance with vaccination recommendations in adolescence has not been well documented in Greece. The aims of the present study were to estimate the vaccination coverage in a sample of adolescents and to identify risk factors associated with incomplete immunization. Α total of 1,005 adolescents aged 11 to 19 years who were outpatient visitors at an Adolescent Health Unit were included in this study. Participation required parental presence and consent and presentation of the official ... [Abstract] [Full-text]

Articles on Diphteria published 19 October 2011:

Rad51 Promoter-Targeted Gene Therapy Is Effective for In Vivo Visualization and Treatment of Cancer.   Mol Ther.

Rad51 protein is overexpressed in a wide range of human cancers. Our previous in vitro studies demonstrated that a construct comprised Rad51 promoter driving expression of the diphtheria toxin A gene (pRad51-diphtheria toxin A (DTA)) destroys a variety of human cancer cell lines, with minimal to no toxicity to normal human cells. Here we delivered Rad51 promoter-based constructs in vivo using linear polyethylenimine nanoparticles, in vivo jetPEI, to visualize and treat tumors in mice with HeLa ... [Abstract] [Full-text]

Development of a diphtheria toxin based antiporcine CD3 recombinant immunotoxin.   Bioconjug Chem, 22(10): 2014-20.

Anti-CD3 immunotoxins, which induce profound but transient T-cell depletion in vivo by inhibiting eukaryotic protein synthesis in CD3+ cells, are effective reagents in large animal models of transplantation tolerance and autoimmune disease therapy. A diphtheria toxin based antiporcine CD3 recombinant immunotoxin was constructed by fusing the truncated diphtheria toxin DT390 with two identical tandem single chain variable fragments (scFv) derived from the antiporcine CD3 monoclonal antibody ... [Abstract] [Full-text]

Articles on Diphteria published 18 October 2011:

Oral macrophage-like cells play a key role in tolerance induction following sublingual immunotherapy of asthmatic mice.   Mucosal Immunol, 4(6): 638-47.

Sublingual allergen-specific immunotherapy (SLIT) is a safe and efficacious treatment for type 1 respiratory allergies. Herein, we investigated the key subset(s) of antigen-presenting cells (APCs) involved in antigen/allergen capture and tolerance induction during SLIT. Following sublingual administration, fluorochrome-labeled ovalbumin (OVA) is predominantly captured by oral CD11b(+)CD11c(-) cells that migrate to cervical lymph nodes (CLNs) and present the antigen to naive CD4(+) T cells. ... [Abstract] [Full-text]

Articles on Diphteria published 17 October 2011:

Antibody persistence at 18-20months of age and safety and immunogenicity of a booster dose of a combined DTaP-IPV//PRP∼T vaccine compared to separate vaccines (DTaP, PRP∼T and IPV) following primary vaccination of healthy infants with in the People's Republic of China.   Vaccine.

This study assessed the antibody persistence, and the immunogenicity and safety of a booster dose of a DTaP-IPV//PRP∼T (Pentaxim(®), Sanofi Pasteur's AcXim family) combined vaccine and of standalone vaccines one year after primary vaccination in the People's Republic of China. Participants (N=719) previously primed with DTaP-IPV//PRP∼T at 2, 3, 4months (Group A, N=255), 3, 4, 5months (Group B, N=233), or DTaP (Wuhan Institute of Biological Products), PRP-T (Act-Hib(®)) and IPV (Imovax(®) ... [Abstract] [Full-text]

A Mid-Term Assessment of Progress towards the Immunisation Coverage Goal of the Global Immunisation Vision and Strategy (GIVS).   BMC Public Health, 11(1): 806.

ABSTRACT: BACKGROUND: The Global Immunization Vision and Strategy (GIVS) (2006-2015) aims to reach and sustain high levels of vaccine coverage, provide immunization services to age groups beyond infancy and to those currently not reached, and to ensure that immunization activities are linked with other health interventions and contribute to the overall development of the health sector. OBJECTIVE. To examine mid-term progress (through 2010) of the immunization coverage goal of the GIVS for ... [Abstract] [Full-text]

Tolerability and antibody response in adolescents and adults revaccinated with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine adsorbed (Tdap) 4-5 years after a previous dose.   Vaccine, 29(46): 8459-65.

[Abstract] [Full-text]

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