scholarly journals Evidence for the existence of a functional helical myocardial band

2009 ◽  
Vol 296 (1) ◽  
pp. H127-H131 ◽  
Author(s):  
Abbas Nasiraei-Moghaddam ◽  
Morteza Gharib
Keyword(s):  
Diffusion Tensor ◽  
Wall Thickening ◽  
Diffusion Tensor Mri ◽  
Displacement Fields ◽  
Left Ventricle Mass ◽  
Global Function ◽  
Helical Bundle ◽  
Form And Function ◽  
And Function

Characterization of local and global contractile activities in the myocardium is essential for a better understanding of cardiac form and function. The spatial distribution of regions that contribute the most to cardiac function plays an important role in defining the pumping parameters of the myocardium like ejection fraction and dynamic aspects such as twisting and untwisting. In general, myocardium shortening, tangent to the wall, and ventricular wall thickening are important parameters that characterize the regional contribution within the myocardium to the global function of the heart. We have calculated these parameters using myocardium displacement fields, which were captured through the displacement-encoding with stimulated echoes (DENSE) MRI technique in three volunteers. High spatial resolution of the acquired data revealed transmural changes of thickening and tangential shortening with high fidelity in beating hearts. By filtering myocardium regions that showed a tangential shortening index of <0.23, we were able to identify the complete or a portion of a macrostructure composed of connected regions in the form of a helical bundle within the left ventricle mass. In this study, we present a representative case that shows the complete morphology of a helical myocardial band as well as two other cases that present ascending and descending portions of the helical myocardial band. Our observation of a helical functional band based on dynamics is in agreement with diffusion tensor MRI observations and gross dissection studies in the arrested heart.

A widespread pathway for substitution of adenine by diaminopurine in phage genomes

Science ◽  
2021 ◽  
Vol 372 (6541) ◽  
pp. 512-516
Author(s):  
Yan Zhou ◽  
Xuexia Xu ◽  
Yifeng Wei ◽  
Yu Cheng ◽  
Yu Guo ◽  
...  
Keyword(s):  
Large Scale ◽  
Restriction Enzymes ◽  
Diverse Range ◽  
Host Restriction ◽  
Form And Function ◽  
Multienzyme System ◽  
Dna Modifications ◽  
Dna Production ◽  
And Function

DNA modifications vary in form and function but generally do not alter Watson-Crick base pairing. Diaminopurine (Z) is an exception because it completely replaces adenine and forms three hydrogen bonds with thymine in cyanophage S-2L genomic DNA. However, the biosynthesis, prevalence, and importance of Z genomes remain unexplored. Here, we report a multienzyme system that supports Z-genome synthesis. We identified dozens of globally widespread phages harboring such enzymes, and we further verified the Z genome in one of these phages, Acinetobacter phage SH-Ab 15497, by using liquid chromatography with ultraviolet and mass spectrometry. The Z genome endows phages with evolutionary advantages for evading the attack of host restriction enzymes, and the characterization of its biosynthetic pathway enables Z-DNA production on a large scale for a diverse range of applications.

scholarly journals Characterization of the myocardium in the 4-chamber view using accelerated free-breathing diffusion tensor MRI

2016 ◽  
Vol 18 (S1) ◽  
Author(s):  
Choukri Mekkaoui ◽  
Timothy G Reese ◽  
Himanshu Bhat ◽  
Marcel P Jackowski ◽  
David E Sosnovik
Keyword(s):  
Diffusion Tensor ◽  
Free Breathing ◽  
Diffusion Tensor Mri ◽  
Chamber View

scholarly journals Identification of osteoclast-specific monoclonal antibodies.

1985 ◽  
Vol 100 (5) ◽  
pp. 1592-1600 ◽  
Author(s):  
M J Oursler ◽  
L V Bell ◽  
B Clevinger ◽  
P Osdoby
Keyword(s):  
Monoclonal Antibodies ◽  
Giant Cells ◽  
Mononuclear Phagocyte ◽  
Antibody Binding ◽  
Enzyme Linked Immunosorbent Assay ◽  
Form And Function ◽  
Titration Curves ◽  
Specific Antigens ◽  
And Function

Studies on the origin, identification, and characterization of osteoclasts have been difficult. This is in part due to a lack of definitive osteoclast markers and the similarity of these cells in form and function to cells of the mononuclear phagocyte system. To solve this problem, we inoculated isolated chick osteoclasts into mice to generate osteoclast-specific monoclonal antibodies. Supernatants from growth-positive hybridomas were screened by indirect immunofluorescent methods against cultured osteoclasts, monocyte-derived multinucleated giant cells, cultured monocytes, fibroblasts, and limb mesenchyme. Select hybridomas were cloned to produce 375 clones, which were analyzed as described above. Antibody from select clones was also reacted with paraffin sections of bone. In addition, two clones have been analyzed by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Antibody binding from an osteoclast-specific clone and a clone reactive with osteoclasts, giant cells, and cultured monocytes (as determined by immunohistochemical assay) was confirmed by antibody-binding and titration curves quantitated by ELISA. The above studies demonstrate that osteoclast specific antigens exist, and that osteoclasts, giant cells, and cultured monocytes share common determinants not found on other cells screened.

scholarly journals To form and function: on the role of basement membrane mechanics in tissue development, homeostasis and disease

Open Biology ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 200360
Author(s):  
Nargess Khalilgharibi ◽  
Yanlan Mao
Keyword(s):  
Basement Membrane ◽  
Molecular Mechanisms ◽  
Disease Diagnosis ◽  
Membrane Mechanics ◽  
Form And Function ◽  
And Function ◽  
Tissue Form

The basement membrane (BM) is a special type of extracellular matrix that lines the basal side of epithelial and endothelial tissues. Functionally, the BM is important for providing physical and biochemical cues to the overlying cells, sculpting the tissue into its correct size and shape. In this review, we focus on recent studies that have unveiled the complex mechanical properties of the BM. We discuss how these properties can change during development, homeostasis and disease via different molecular mechanisms, and the subsequent impact on tissue form and function in a variety of organisms. We also explore how better characterization of BM mechanics can contribute to disease diagnosis and treatment, as well as development of better in silico and in vitro models that not only impact the fields of tissue engineering and regenerative medicine, but can also reduce the use of animals in research.

scholarly journals Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

2017 ◽  
Vol 21 (7) ◽  
pp. 3749-3775 ◽  
Author(s):  
Conrad Jackisch ◽  
Lisa Angermann ◽  
Niklas Allroggen ◽  
Matthias Sprenger ◽  
Theresa Blume ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Soil Water ◽  
Time Lapse ◽  
Saturated Hydraulic Conductivity ◽  
Form And Function ◽  
And Function ◽  
Hillslope Scale

Abstract. The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

scholarly journals Characterization of White Matter Injury in a Hypoxic-Ischemic Neonatal Rat Model by Diffusion Tensor MRI

Stroke ◽  
2008 ◽  
Vol 39 (8) ◽  
pp. 2348-2353 ◽  
Author(s):  
Silun Wang ◽  
Ed X. Wu ◽  
Chung Nga Tam ◽  
Ho-Fai Lau ◽  
Pik-To Cheung ◽  
...  
Keyword(s):  
White Matter ◽  
Rat Model ◽  
Diffusion Tensor ◽  
White Matter Injury ◽  
Neonatal Rat ◽  
Diffusion Tensor Mri ◽  
Neonatal Rat Model

scholarly journals Diffusion tensor cardiovascular magnetic resonance

2019 ◽  
Vol 95 (1126) ◽  
pp. 433-438
Author(s):  
Zohya Khalique ◽  
Dudley Pennell
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Cardiac Cycle ◽  
Diffusion Tensor ◽  
Dynamic Assessment ◽  
Wall Thickening ◽  
Macroscopic Scale ◽  
Novel Technique ◽  
And Function

Cardiac structure and function are complex and inter-related. Current in vivo techniques assess the heart on a macroscopic scale, but a novel technique called diffusion tensor cardiovascular magnetic resonance (DT-CMR) can now assess the cardiac microstructure non-invasively. It provides information on the helical arrangement of cardiomyocytes that drives torsion and offers dynamic assessment of the sheetlets (aggregated cardiomyocytes) that rotate through the cardiac cycle to facilitate wall thickening. Through diffusion biomarkers, the expansion and organisation of the underlying myocardium can be described. DT-CMR has already identified novel microstructural abnormalities in cardiomyopathy, and ischaemic and congenital heart disease. This new knowledge supports the potential of DT-CMR to improve diagnostics and prognostication in various cardiac diseases.

Regional ventricular wall thickening reflects changes in cardiac fiber and sheet structure during contraction: quantification with diffusion tensor MRI

2005 ◽  
Vol 289 (5) ◽  
pp. H1898-H1907 ◽  
Author(s):  
Junjie Chen ◽  
Wei Liu ◽  
Huiying Zhang ◽  
Liz Lacy ◽  
Xiaoxia Yang ◽  
...  
Keyword(s):  
Diffusion Tensor ◽  
Helix Angle ◽  
Myocardial Contraction ◽  
Wall Thickening ◽  
Diffusion Tensor Mri ◽  
Sprague Dawley ◽  
Active Components ◽  
Myocardial Fiber ◽  
Sheet Structure ◽  
Cardiac Fiber

Dynamic changes of myocardial fiber and sheet structure are key determinants of regional ventricular function. However, quantitative characterization of the contraction-related changes in fiber and sheet structure has not been reported. The objective of this study was to quantify cardiac fiber and sheet structure at selected phases of the cardiac cycle. Diffusion tensor MRI was performed on isolated, perfused Sprague-Dawley rat hearts arrested or fixed in three states as follows: 1) potassium arrested (PA), which represents end diastole; 2) barium-induced contracture with volume (BV+), which represents isovolumic contraction or early systole; and 3) barium-induced contracture without volume (BV−), which represents end systole. Myocardial fiber orientations at the base, midventricle, and apex were determined from the primary eigenvectors of the diffusion tensor. Sheet structure was determined from the secondary and tertiary eigenvectors at the same locations. We observed that the transmural distribution of the myofiber helix angle remained unchanged as contraction proceeded from PA to BV+, but endocardial and epicardial fibers became more longitudinally orientated in the BV− group. Although sheet structure exhibited significant regional variations, changes in sheet structure during myocardial contraction were relatively uniform across regions. The magnitude of the sheet angle, which is an index of local sheet slope, decreased by 23 and 44% in BV+ and BV− groups, respectively, which suggests more radial orientation of the sheet. In summary, we have shown for the first time that geometric changes in both sheet and fiber orientation provide a substantial mechanism for radial wall thickening independent of active components due to myofiber shortening. Our results provide direct evidence that sheet reorientation is a primary determinant of myocardial wall thickening.

scholarly journals Interactions of Symbiotic Partners Drive the Development of a Complex Biogeography in the Squid-Vibrio Symbiosis

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Tara Essock-Burns ◽  
Clotilde Bongrand ◽  
William E. Goldman ◽  
Edward G. Ruby ◽  
Margaret J. McFall-Ngai
Keyword(s):  
Vibrio Fischeri ◽  
Antibiotic Sensitivity ◽  
Host Tissue ◽  
Live Cells ◽  
Content Type ◽  
Form And Function ◽  
And Function ◽  
Molecular Patterns ◽  
The Impact

ABSTRACT Microbes live in complex microniches within host tissues, but how symbiotic partners communicate to create such niches during development remains largely unexplored. Using confocal microscopy and symbiont genetics, we characterized the shaping of host microenvironments during light organ colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri. During embryogenesis, three pairs of invaginations form sequentially on the organ’s surface, producing pores that lead to interior compressed tubules at different stages of development. After hatching, these areas expand, allowing V. fischeri cells to enter and migrate ∼120 μm through three anatomically distinct regions before reaching blind-ended crypt spaces. A dynamic gatekeeper, or bottleneck, connects these crypts with the migration path. Once V. fischeri cells have entered the crypts, the bottlenecks narrow, and colonization by the symbiont population becomes spatially restricted. The actual timing of constriction and restriction varies with crypt maturity and with different V. fischeri strains. Subsequently, starting with the first dawn following colonization, the bottleneck controls a lifelong cycle of dawn-triggered expulsions of most of the symbionts into the environment and a subsequent regrowth in the crypts. Unlike other developmental phenotypes, bottleneck constriction is not induced by known microbe-associated molecular patterns (MAMPs) or by V. fischeri-produced bioluminescence, but it does require metabolically active symbionts. Further, while symbionts in the most mature crypts have a higher proportion of live cells and a greater likelihood of expulsion at dawn, they have a lower resistance to antibiotics. The overall dynamics of these distinct microenvironments reflect the complexity of the host-symbiont dialogue. IMPORTANCE The complexity, inaccessibility, and time scales of initial colonization of most animal microbiomes present challenges for the characterization of how the bacterial symbionts influence the form and function of tissues in the minutes to hours following the initial interaction of the partners. Here, we use the naturally occurring binary squid-vibrio association to explore this phenomenon. Imaging of the spatiotemporal landscape of this symbiosis during its onset provides a window into the impact of differences in both host-tissue maturation and symbiont strain phenotypes on the establishment of a dynamically stable symbiotic system. These data provide evidence that the symbionts shape the host-tissue landscape and that tissue maturation impacts the influence of strain-level differences on the daily rhythms of the symbiosis, the competitiveness for colonization, and antibiotic sensitivity.

scholarly journals Tripartite Mushroom Body Architecture Revealed by Antigenic Markers

1998 ◽  
Vol 5 (1) ◽  
pp. 38-51 ◽  
Author(s):  
Jill R. Crittenden ◽  
Efthimios M.C. Skoulakis ◽  
Kyung-An Han ◽  
Daniel Kalderon ◽  
Ronald L. Davis
Keyword(s):  
Mushroom Body ◽  
Dorsal Surface ◽  
Mushroom Bodies ◽  
Lateral Projection ◽  
Body Cell ◽  
Expression Levels ◽  
Form And Function ◽  
Immunohistochemical Markers ◽  
And Function

We have explored the organization of the axonal lobes in Drosophila mushroom bodies by using a panel of immunohistochemical markers. These markers consist of antibodies to eight proteins expressed preferentially in the mushroom bodies: DAMB, DCO, DRK, FASII, LEO, OAMB, PKA RII, and RUT. Previous to this work, four axonal lobes, two projecting dorsally (α and α′) and two medially (β and γ), had been described inDrosophila mushroom bodies. However, our analysis of immunohistochemically stained frontal and sagittal sections of the brain revealed three medially projecting lobes. The newly distinguished lobe, which we term β′, lies along the dorsal surface of β, just posterior to γ. In addition to resolving a fifth lobe, our studies revealed that there are specific lobe sets defined by equivalent marker expression levels. These sets are (1) the α and β lobes, (2) the α′ and β′ lobes, and (3) the γ lobe and heel (a lateral projection formed by a hairpin turn of some of the peduncle fibers). All of the markers we have examined are consistent with these three sets. Previous Golgi studies demonstrate that each mushroom body cell projects one axon that branches into a dorsal lobe and a medial lobe, or one unbranched axon that projects medially. Taken together with the lobe sets listed above, we propose that there are three major projection configurations of mushroom body cell axons: (1) one branch in the α and one in the β lobe, (2) one branch in the α′ and one in the β′ lobe, and (3) one unbranched axon projecting to the heel and the γ lobe. The fact that these neuron types exhibit differential expression levels of a number of mushroom body genes suggests that they may have corresponding functional differences. These functions may be conserved in the larvae, as several of these genes were expressed in larval and embryonic mushroom bodies as well. The basic mushroom body structure, including the denritic calyx, peduncle, and lobes, was already visible by the late stages of embryogenesis. With new insights into mushroom body organization, and the characterization of markers for developing mushroom bodies, we are beginning to understand how these structures form and function.

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