Sequentially based analysis versus image based analysis of Intima Media Thickness in common carotid arteries studies - Do major IMT studies underestimate the true relations for cardio- and cerebrovascular risk?

<p>Abstract</p> <p>Background</p> <p>Image-based B-mode ultrasound has gained popularity in major studies as a non-invasive method of measuring cardio- and cerebrovascular risk factors. However, none of the major studies appears to have paid sufficient attention to the variation in end diastolic wall process. By using sequentially based analyses (SBA) of Intima-Media Thickness (IMT), the general purpose of this study was to show that the current image based (ECG tracked) analysis (IBA) has some major variations and might underestimate the true relations for cardiovascular events and stroke for IMT measurement.</p> <p>Method</p> <p>The study group consisted of 2500 healthy male subjects aged between 35 to 55 years. 4 sequences (300 images) were analyzed per subject. 750,000 images were analysed throughout the course of this study.</p> <p>Results</p> <p>IBA showed significantly lower mean, maximal, and minimal values for IMT in CCA than for SBA. The correlation analysis between IBA and SBA with the cardio- and cerebrovascular risk factors showed a higher correlation of SBA for all risk factors. The Pearson coefficient was 0.81, p < 0.01, for SBA versus Framingham CHD risk level (FCRL) and 0.49, p = 0.01, for IBA versus FCRL.</p> <p>Conclusion</p> <p>IBA did not measure the true maximal values of the IMT in this study. Together with the correlation analysis, this indicates that IBA might underestimate the true relations for IMT and risk factors.</p

The Anti-Ischemic and Anti-Anginal Properties of Statins

Angina pectoris resulting from myocardial ischemia afflicts half of all patients with coronary heart disease (CHD). Chronic angina remains a major public health burden despite state-of-the-art therapies, and improvement in survival from myocardial infarction and CHD has only increased its prevalence. There is growing experimental and clinical evidence pointing to the anti-ischemic and anti-anginal properties of statins. Some data suggest that the degree of anti-ischemic efficacy of statins may be comparable to the current standard pharmacologic and mechanical strategies. The pleiotropic effects of statins are postulated to be primarily responsible for their anti-ischemic and anti-anginal properties. These include improvement of endothelial function, enhancement of the ischemic vasodilatory response, modulation of inflammation, and protection from ischemia-reperfusion injury. The anti-ischemic effects of statins further strengthen their role as a crucial component of the optimal medical therapy for CHD

An Intergenic Region Shared by At4g35985 and At4g35987 in Arabidopsis Thaliana is a Tissue Specific and Stress Inducible Bidirectional Promoter Analyzed in Transgenic Arabidopsis and Tobacco Plants

On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985) are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS) in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85) showed stronger expression (about 3.5 fold) compared to the At4g35987 promoter (P87). The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold) under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications

Sterility and Gene Expression in Hybrid Males of Xenopus laevis and X. muelleri

BACKGROUND: Reproductive isolation is a defining characteristic of populations that represent unique biological species, yet we know very little about the gene expression basis for reproductive isolation. The advent of powerful molecular biology tools provides the ability to identify genes involved in reproductive isolation and focuses attention on the molecular mechanisms that separate biological species. Herein we quantify the sterility pattern of hybrid males in African Clawed Frogs (Xenopus) and apply microarray analysis of the expression pattern found in testes to identify genes that are misexpressed in hybrid males relative to their two parental species (Xenopus laevis and X. muelleri). METHODOLOGY/PRINCIPAL FINDINGS: Phenotypic characteristics of spermatogenesis in sterile male hybrids (X. laevis x X. muelleri) were examined using a novel sperm assay that allowed quantification of live, dead, and undifferentiated sperm cells, the number of motile vs. immotile sperm, and sperm morphology. Hybrids exhibited a dramatically lower abundance of mature sperm relative to the parental species. Hybrid spermatozoa were larger in size and accompanied by numerous undifferentiated sperm cells. Microarray analysis of gene expression in testes was combined with a correction for sequence divergence derived from genomic hybridizations to identify candidate genes involved in the sterility phenotype. Analysis of the transcriptome revealed a striking asymmetric pattern of misexpression. There were only about 140 genes misexpressed in hybrids compared to X. laevis but nearly 4,000 genes misexpressed in hybrids compared to X. muelleri. CONCLUSIONS/SIGNIFICANCE: Our results provide an important correlation between phenotypic characteristics of sperm and gene expression in sterile hybrid males. The broad pattern of gene misexpression suggests intriguing mechanisms creating the dominance pattern of the X. laevis genome in hybrids. These findings significantly contribute to growing evidence for allelic dominance in hybrids and have implications for the mechanism of species differentiation at the transcriptome level

Structural evolution and flip-flop recombination of chloroplast DNA in the fern genus Osmunda

The evolution and recombination of chloroplast genome structure in the fern genus Osmunda were studied by comparative restriction site mapping and filter hybridization of chloroplast DNAs (cpDNAs) from three species — 0. cinnamomea, 0. claytoniana and 0. regalis . The three 144 kb circular genomes were found to be colinear in organization, indicating that no major inversions or transpositions had occurred during the approximately 70 million years since their radiation from a common ancestor. Although overall size and sequence arrangement are highly conserved in the three genomes, they differ by an extensive series of small deletions and insertions, ranging in size from 50 bp to 350 by and scattered more or less at random throughout the circular chromosomes. All three chloroplast genomes contain a large inverted repeat of approximately 10 kb in size. However, hybridizations using cloned fragments from the 0. cinnamomea and 0. regalis genomes revealed the absence of any dispersed repeats in at least 50% of the genome. Analysis with restriction enzymes that fail to cleave the 10 kb inverted repeat indicated that each of the three fern chloroplast genomes exists as an equimolar population of two isomeric circles differing only in the relative orientation of their two single copy regions. These two inversion isomers are inferred to result from high frequency intramolecular recombination between paired inverted repeat segments. In all aspects of their general organization, recombinational heterogeneity, and extent of structural rearrangement and length mutation, these fern chloroplast genomes resemble very closely the chloroplast genomes of most angiosperms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46956/1/294_2004_Article_BF00418530.pd

Conservation of chloroplast genome structure among vascular plants

We have constructed the first physical map of a gymnosperm chloroplast genome and compared its organization with those of a fern and several angiosperms by heterologous filter hybridization. The chloroplast genome of the gymnosperm Ginkgo biloba consists of a 158 kb circular chromosome that contains a ribosomal RNA-encoding inverted repeat approximately 17 kb in size. Gene mapping experiments demonstrate a remarkable similarity in the linear order and absolute positions of the ribosomal RNA genes and of 17 protein genes in the cpDNAs of Ginkgo biloba , the fern Osmunda cinnamomea and the angiosperm Spinacia oleracea . Moreover, filter hybridizations using as probes cloned fragments that cover the entirety of the angiosperm chloroplast genome reveal a virtually colinear arrangement of homologous sequence elements in these genomes representing three divisions of vascular plants that diverged some 200–400 million years ago. The only major difference in chloroplast genome structure among these vascular plants involves the size of the rRNA-encoding inverted repeat, which is only 10 kb in Osmunda , 17 kb in Ginkgo , and about 25 kb in most angiosperms. This size variation appears to be the result of spreading of the repeat through previously single copy sequences, or the reverse process of shrinkage, unaccompanied by any overall change in genome complexity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46955/1/294_2004_Article_BF00418529.pd