Three-Dimensional Myocardial Perfusion Maps by Contrast Echocardiography

We evaluated the clinical applicability of a system for three-dimensional (3-D) display of a perfusion map following myocardial contrast echocardiography (MCE). The system was used in 12 patients (9 males and 3 females, mean age 52 ± 10 years) undergoing interventional treatment of chronic total coronary occlusion. In each patient three standard apical views were acquired at baseline with sonicated IopamidolR injections into the left coronary artery (LCA) and into the right coronary artery (RCA). Following successful recanalization of the occluded artery MCE was repeated. The patients tolerated the procedure well. Acquisition of three standard apical views provided sufficient information for the reconstruction of 3-D perfusion maps containing the 16 standard left ventricular (LV) segments. Side-by-side display of the perfusion maps obtained following LCA and RCA echocontrast injections allowed us to classify the myocardial segments (192) into three groups: (1) those supplied by one major artery (124); (2) those supplied by collaterals from contralateral or both major arteries (58); and (3) segments supplied by none of the major arteries (10). Decreased opacification was observed in 50 segme

Rise in Chronic Defibrillation Energy Requirements Necessitating Implantable Defibrillator Lead System Revision

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72617/1/j.1540-8159.1997.tb03890.x.pd

Phylogenetic nomenclature and evolution of mannose-binding lectin (MBL2) haplotypes

<p>Abstract</p> <p>Background</p> <p>Polymorphisms of the mannose-binding lectin gene (<it>MBL2</it>) affect the concentration and functional efficiency of the protein. We recently used haplotype-specific sequencing to identify 23 <it>MBL2 </it>haplotypes, associated with enhanced susceptibility to several diseases.</p> <p>Results</p> <p>In this work, we applied the same method in 288 and 470 chromosomes from Gabonese and European adults, respectively, and found three new haplotypes in the last group. We propose a phylogenetic nomenclature to standardize <it>MBL2 </it>studies and found two major phylogenetic branches due to six strongly linked polymorphisms associated with high MBL production. They presented high Fst values and were imbedded in regions with high nucleotide diversity and significant Tajima's D values. Compared to others using small sample sizes and unphased genotypic data, we found differences in haplotyping, frequency estimation, Fu and Li's D* and Fst results.</p> <p>Conclusion</p> <p>Using extensive testing for selective neutrality, we confirmed that stochastic evolutionary factors have had a major role in shaping this polymorphic gene worldwide.</p

Design principles for riboswitch function

Scientific and technological advances that enable the tuning of integrated regulatory components to match network and system requirements are critical to reliably control the function of biological systems. RNA provides a promising building block for the construction of tunable regulatory components based on its rich regulatory capacity and our current understanding of the sequence–function relationship. One prominent example of RNA-based regulatory components is riboswitches, genetic elements that mediate ligand control of gene expression through diverse regulatory mechanisms. While characterization of natural and synthetic riboswitches has revealed that riboswitch function can be modulated through sequence alteration, no quantitative frameworks exist to investigate or guide riboswitch tuning. Here, we combined mathematical modeling and experimental approaches to investigate the relationship between riboswitch function and performance. Model results demonstrated that the competition between reversible and irreversible rate constants dictates performance for different regulatory mechanisms. We also found that practical system restrictions, such as an upper limit on ligand concentration, can significantly alter the requirements for riboswitch performance, necessitating alternative tuning strategies. Previous experimental data for natural and synthetic riboswitches as well as experiments conducted in this work support model predictions. From our results, we developed a set of general design principles for synthetic riboswitches. Our results also provide a foundation from which to investigate how natural riboswitches are tuned to meet systems-level regulatory demands

GlycoForm and Glycologue: two software applications for the rapid construction and display of N-glycans from mammalian sources

<p>Abstract</p> <p>Background</p> <p>The display of <it>N</it>-glycan carbohydrate structures is an essential part of glycoinformatics. Several tools exist for building such structures graphically, by selecting from a palette of symbols or sugar names, or else by specifying a structure in one of the chemical naming schemes currently available.</p> <p>Findings</p> <p>In the present work we present two tools for displaying <it>N</it>-glycans found in the mammalian CHO (Chinese hamster ovary) cell line, both of which take as input a 9-digit identifier that uniquely defines each structure. The first of these, GlycoForm, is designed to display a single structure automatically from an identifier entered by the user. The display is updated in real time, using symbols for the sugar residues, or in text-only form. Structures can be added to a library, which is recorded in a preference file and loaded automatically at start. Individual structures can be saved in a variety of bitmap image formats. The second program, Glycologue, reads a file containing columnar data of nine-digit codes, which can be displayed on-screen and printed at high resolution.</p> <p>Conclusion</p> <p>A key advantage of both programs is the speed and facility with which carbohydrate structures can be drawn. It is anticipated that these programs will be useful to glycobiologists, systems biologists and biotechnologists interested in <it>N</it>-glycosylation systems in mammalian cells.</p

Contributions to early HIV diagnosis among patients linked to care vary by testing venue

<p>Abstract</p> <p>Objective</p> <p>Early HIV diagnosis reduces transmission and improves health outcomes; screening in non-traditional settings is increasingly advocated. We compared test venues by the number of new diagnoses successfully linked to the regional HIV treatment center and disease stage at diagnosis.</p> <p>Methods</p> <p>We conducted a retrospective cohort study using structured chart review of newly diagnosed HIV patients successfully referred to the region's only HIV treatment center from 1998 to 2003. Demographics, testing indication, risk profile, and initial CD4 count were recorded.</p> <p>Results</p> <p>There were 277 newly diagnosed patients meeting study criteria. Mean age was 33 years, 77% were male, and 46% were African-American. Median CD4 at diagnosis was 324. Diagnoses were earlier via partner testing at the HIV treatment center (N = 8, median CD4 648, p = 0.008) and with universal screening by the blood bank, military, and insurance companies (N = 13, median CD4 483, p = 0.05) than at other venues. Targeted testing by health care and public health entities based on patient request, risk profile, or patient condition lead to later diagnosis.</p> <p>Conclusion</p> <p>Test venues varied by the number of new diagnoses made and the stage of illness at diagnosis. To improve the rate of early diagnosis, scarce resources should be allocated to maximize the number of new diagnoses at screening venues where diagnoses are more likely to be early or alter testing strategies at test venues where diagnoses are traditionally made late. Efforts to improve early diagnosis should be coordinated longitudinally on a regional basis according to this conceptual paradigm.</p

Sodium and Health: Old Myths and a Controversy Based on Denial

Purpose of Review The scientific consensus on which global health organizations base public health policies is that high sodium intake increases blood pressure (BP) in a linear fashion contributing to cardiovascular disease (CVD). A moderate reduction in sodium intake to 2000 mg per day helps ensure that BP remains at a healthy level to reduce the burden of CVD. Recent Findings Yet, since as long ago as 1988, and more recently in eight articles published in the European Heart Journal in 2020 and 2021, some researchers have propagated a myth that reducing sodium does not consistently reduce CVD but rather that lower sodium might increase the risk of CVD. These claims are not well-founded and support some food and beverage industry’s vested interests in the use of excessive amounts of salt to preserve food, enhance taste, and increase thirst. Nevertheless, some researchers, often with funding from the food industry, continue to publish such claims without addressing the numerous objections. This article analyzes the eight articles as a case study, summarizes misleading claims, their objections, and it offers possible reasons for such claims. Summary Our study calls upon journal editors to ensure that unfounded claims about sodium intake be rigorously challenged by independent reviewers before publication; to avoid editorial writers who have been co-authors with the subject paper’s authors; to require statements of conflict of interest; and to ensure that their pages are used only by those who seek to advance knowledge by engaging in the scientific method and its collegial pursuit. The public interest in the prevention and treatment of disease requires no less

Detection of emphysema progression in alpha 1-antitrypsin deficiency using CT densitometry; Methodological advances

<p>Abstract</p> <p>Background</p> <p>Computer tomography (CT) densitometry is a potential tool for detecting the progression of emphysema but the optimum methodology is uncertain. The level of inspiration affects reproducibility but the ability to adjust for this variable is facilitated by whole lung scanning methods. However, emphysema is frequently localised to sub-regions of the lung and targeted densitometric sampling may be more informative than whole lung assessment.</p> <p>Methods</p> <p>Emphysema progression over a 2-year interval was assessed in 71 patients (alpha 1-antitrypsin deficiency with PiZ phenotype) with CT densitometry, using the 15^thpercentile point (Perc15) and voxel index (VI) -950 Hounsfield Units (HU) and -910 HU (VI -950 and -910) on whole lung, limited single slices, and apical, central and basal thirds. The relationship between whole lung densitometric progression (ΔCT) and change in CT-derived lung volume (ΔCT_Vol) was characterised, and adjustment for lung volume using statistical modelling was evaluated.</p> <p>Results</p> <p>CT densitometric progression was statistically significant for all methods. ΔCT correlated with ΔCT_Voland linear regression indicated that nearly one half of lung density loss was secondary to apparent hyperinflation. The most accurate measure was obtained using a random coefficient model to adjust for lung volume and the greatest progression was detected by targeted sampling of the middle third of the lung.</p> <p>Conclusion</p> <p>Progressive hyperinflation may contribute significantly to loss of lung density, but volume effects and absolute tissue loss can be identified by statistical modelling. Targeted sampling of the middle lung region using Perc15 appears to be the most robust measure of emphysema progression.</p