Induction of multifunctional human immunodeficiency virus type 1 (HIV-1)-specific T cells capable of proliferation in healthy subjects by using a prime-boost regimen of DNA- and modified vaccinia virus Ankara-vectored vaccines expressing HIV-1 Gag coupled to CD8+ T-cell epitopes

A double-blind randomized phase I trial was conducted in human immunodeficiency virus type 1 (HIV-1)-negative subjects receiving vaccines vectored by plasmid DNA and modified vaccinia virus Ankara (MVA) expressing HIV-1 p24/p17 gag linked to a string of CD8(+) T-cell epitopes. The trial had two groups. One group received either two doses of MVA.HIVA (2x MVA.HIVA) (n=8) or two doses of placebo (2x placebo) (n=4). The second group received 2x pTHr.HIVA followed by one dose of MVA.HIVA (n=8) or 3x placebo (n=4). In the pTHr.HIVA-MVA.HIVA group, HIV-1-specific T-cell responses peaked 1 week after MVA.HIVA vaccination in both ex vivo gamma interferon (IFN-gamma) ELISPOT (group mean, 210 spot-forming cells/10(6) cells) and proliferation (group mean stimulation index, 37), with assays detecting positive responses in four out of eight and five out of eight subjects, respectively. No HIV-1-specific T-cell responses were detected in either assay in the 2x MVA.HIVA group or subjects receiving placebo. Using a highly sensitive and reproducible cultured IFN-gamma ELISPOT assay, positive responses mainly mediated by CD4(+) T cells were detected in eight out of eight vaccinees in the pTHr.HIVA-MVA.HIVA group and four out of eight vaccinees in the 2x MVA.HIVA group. Importantly, no false-positive responses were detected in the eight subjects receiving placebo. Of the 12 responders, 11 developed responses to previously identified immunodominant CD4(+) T-cell epitopes, with 6 volunteers having responses to more than one epitope. Five out of 12 responders also developed CD8(+) T-cell responses to the epitope string. Induced T cells produced a variety of anti-viral cytokines, including tumor necrosis factor alpha and macrophage inflammatory protein 1 beta. These data demonstrate that prime-boost vaccination with recombinant DNA and MVA vectors can induce multifunctional HIV-1-specific T cells in the majority of vaccinees.     

The parvovirus capsid odyssey: from the cell surface to the nucleus

During cellular entry and infection, the parvovirus capsid follows a complex path from the cell surface to the nucleus, where the DNA is replicated. Various receptors have been characterized that bind to different parvoviruses and mediate their entry into cells. However, the subsequent trafficking pathways within the endosomal system, cytoplasm and into the nucleus are still not well defined. Studies of viruses entering various cell types under different conditions show particles located in many different endosomal compartments, within the cytoplasm and in the nucleus with significant variations in timing and distribution. Here, we define the previously unresolved issues that are now better understood for the infection pathways of these viruses, and outline some of the areas that remain to be clarified in future studies.     

Divergence of odorant signals within and between the two European subspecies of the house mouse

The olfactory acuity of mice allows them to discriminate odorsof conspecifics differing by a few genes. This acuity is usedin habituation procedures where investigation of novel odorsby the mouse can be translated into relative difference or similaritybetween the stimuli. This study adapts these behavioral proceduresto address suprapopulation divergence among urinary odors inthe house mouse. Specifically, we investigate geographical patternsof odor divergence within and between 2 subspecies of the housemouse, Mus musculus musculus and Mus musculus domesticus, whichdiverged in allopatry and met secondarily in Europe where theyhybridize. Based on M. m. musculus perception, our study suggeststhat odors of the 2 subspecies differ in both allopatric andcontact zone populations and that divergence is more markedin the latter. Our earlier studies documented mate preferenceand signal divergence between the 2 subspecies. Hence, we considerthe role of the urinary odors as mating signals. We discusshow signal divergence between the 2 subspecies may relate toreproductive character displacement. This study validates theuse of habituation procedures to reconstruct geographical patternsof odorant signal divergence, providing a strong methodologicalplatform to address reproductive character displacement affectingcryptic mating signals in mammals.     

Boundary swapping in the Drosophila Bithorax complex

Although the boundary elements of the Drosophila Bithorax complex (BX-C) have properties similar to chromatin insulators, genetic substitution experiments have demonstrated that these elements do more than simply insulate adjacent cis-regulatory domains. Many BX-C boundaries lie between enhancers and their target promoter, and must modulate their activity to allow distal enhancers to communicate with their target promoter. Given this complex function, it is surprising that the numerous BX-C boundaries share little sequence identity. To determine the extent of the similarity between these elements, we tested whether different BX-C boundary elements can functionally substitute for one another. Using gene conversion, we exchanged the Fab-7 and Fab-8 boundaries within the BX-C. Although the Fab-8 boundary can only partially substitute for the Fab-7 boundary, we find that the Fab-7 boundary can almost completely replace the Fab-8 boundary. Our results suggest that although boundary elements are not completely interchangeable, there is a commonality to the mechanism by which boundaries function. This commonality allows different DNA-binding proteins to create functional boundaries.     

Analytical investigation of styrax and benzoin balsams by HPLC- PAD-fluorimetry and GC-MS

An HPLC and GC study has been conducted on the aromatic oleoresins styrax and benzoin produced by several American, Mediterranean and East-Asian trees, and widely used in ancient civilisations for their therapeutic and odoriferous properties. Initial experiments were performed by HPLC-PAD-fluorimetry for the analysis of several aromatic components, and then completed by GC-MS for the characterisation of both aromatic and triterpenic derivatives. In this work, it was crucial to isolate from fresh natural exudates, and to characterise by two-dimensional NMR, some of the major constituents in order to extend the standard molecular pool prior to chromatographic identifications. This study reveals coniferyl benzoate as an excellent distinctive fluorescent biomarker of Siam benzoin substrate. It also confirms that fluorimetric-coupled detection is a powerful analytical tool for the identification of compounds in Hamamelidaceae extracts that are almost undetectable by UV. GC-MS was successfully applied to the determination of the botanical origin of Sumatra benzoin, and to the identification of lupeol [3beta-lup-20(29)-en-3-ol] for the first time in such balsam-type materials.     

Nontoxic strains of cyanobacteria are the result of major gene deletion events induced by a transposable element

Blooms that are formed by cyanobacteria consist of toxic and nontoxic strains. The mechanisms that result in the occurrence of nontoxic strains are enigmatic. All the nontoxic strains of the filamentous cyanobacterium Planktothrix that were isolated from 9 European countries were found to have lost 90% of a large microcystin synthetase (mcy) gene cluster that encoded the synthesis of the toxic peptide microcystin (MC). Those strains still contain the flanking regions of the mcy gene cluster along with remnants of the transposable elements that are found in between. The majority of the strains still contain a gene coding for a distinct thioesterase type II (mcyT), which is putatively involved in MC synthesis. The insertional inactivation of mcyT in an MC-producing strain resulted in the reduction of MC synthesis by 94 +/- 2% (1 standard deviation). Nontoxic strains that occur in shallow lakes throughout Europe form a monophyletic lineage. A second lineage consists of strains that contain the mcy gene cluster but differ in their photosynthetic pigment composition, which is due to the occurrence of strains that contain phycocyanin or large amounts of phycoerythrin in addition to phycocyanin. Strains containing phycoerythrin typically occur in deep-stratified lakes. The rare occurrence of gene cluster deletion, paired with the evolutionary diversification of the lineages of strains that lost or still contain the mcy gene cluster, needs to be invoked in order to explain the absence or dominance of toxic cyanobacteria in various habitats.     

Functional markers for selection of potyvirus resistance alleles at the pvr2-eIF4E locus in pepper using tetra-primer ARMS-PCR

Functional markers targeted on single nucleotide polymorphisms (SNPs) responsible for phenotypic variation constitute optimal tools for marker-assisted selection (MAS) of resistance alleles with different specificities. Here, we used the tetra-primer ARMS-PCR procedure to assay SNP signatures of four distinct alleles at the pvr2-eIF4E locus, which controls pepper resistance to several potyviruses. These simple, economical, and codominant markers open the way for MAS of pepper genotypes resistant to the potyviral strains and species that are prevalent in distinct cultivation areas across the world.     

Diagnosis and treatment of dementia: 4. Approach to management of mild to moderate dementia

Background

The management of mild to moderate dementia presents complex and evolving challenges. Practising physicians are often uncertain about the appropriate approaches to issues such as the disclosure of the diagnosis, driving and caregiver support. In this article, we provide practical guidance on management based on recommendations from the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia.

Methods

We developed evidence-based guidelines using systematic literature searches, with specific criteria for the selection and quality assessment of articles, and a clear and transparent decision-making process. We selected articles published from January 1996 to December 2005 that dealt with the management of mild to moderate stages of Alzheimer disease and other forms of dementia. Recommendations based on the literature review were drafted and voted on. Consensus required 80% or more agreement by participants. Subsequent to the conference, we searched for additional articles published from January 2006 to April 2008 using the same major keywords and secondary search terms. We graded the strength of evidence using the criteria of the Canadian Task Force on Preventive Health Care.

Results

We identified 1615 articles, of which 954 were selected for further study. From a synthesis of the evidence in these studies, we made 48 recommendations for the management of mild to moderate dementia (28) and dementia with a cerebrovascular component (8) as well as recommendations for addressing ethical issues (e.g., disclosure of the diagnosis) (12). The updated literature review did not change these recommendations. In brief, patients and their families should be informed of the diagnosis. Although the specifics of managing comorbid conditions might require modification, standards of care and treatment targets would not change because of a mild dementia. The use of medications with anticholinergic effects should be minimized. There should be proactive planning for driving cessation, since this will be required at some point in the course of progressive dementia. The patient''s ability to drive should be determined primarily on the basis of his or her functional abilities. An important aspect of care is supporting the patient''s primary caregiver.

Interpretation

Much has been learned about the care of patients with mild to moderate dementia and the support of their primary caregivers. There is a pressing need for the development, and dissemination, of collaborative systems of care.

Articles to date in this series

• Chertkow H. Diagnosis and treatment of dementia: Introduction. Introducing a series based on the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia. CMAJ 2008;178:316-21.
• Patterson C, Feightner JW, Garcia A, et al. Diagnosis and treatment of dementia: 1. Risk assessment and primary prevention of Alzheimer disease. CMAJ 2008;178:548-56.
• Feldman HH, Jacova C, Robillard A, et al. Diagnosis and treatment of dementia: 2. Diagnosis. CMAJ 2008;178:825-36.
• Chertkow H, Massoud F, Nasreddine Z, et al. Diagnosis and treatment of dementia: 3. Mild cognitive impairment and cognitive impairment without dementia. CMAJ 2008;178: 1273-85.

     

HMWMAP2: new perspectives on a pathway to dendritic identity

Neuronal polarity is established by the differentiation of two types of cytoplasmic processes: dendrites and the axon. These processes can be distinguished by their composition in microtubule-associated proteins, the high molecular weight MAP2 proteins (HMWMAP2) being found in the dendrites and tau proteins in the axon. It is believed that the main contribution of HMWMAP2 to the acquisition and maintenance of dendrites is to promote microtubule assembly and stability. However, recent studies force us to enlarge our view on how HMWMAP2 might contribute to defining the role of the dendritic microtubules. The purpose of this article is to convey our view that HMWMAP2 are important players in defining the contribution of microtubules to dendritic identity by anchoring membranous organelles and signaling proteins to the dendritic microtubules and by being a receptor for neurosteroids.