scholarly journals Characterization of Simultaneous Pressure Waves as Biomarkers for Colonic Motility Assessed by High-Resolution Colonic Manometry

2018 ◽  
Vol 9 ◽  
Author(s):  
Ji-Hong Chen ◽  
Sean P. Parsons ◽  
Mitra Shokrollahi ◽  
Andrew Wan ◽  
Alexander D. Vincent ◽  
...  
Keyword(s):  
High Resolution ◽  
Colonic Motility ◽  
Pressure Waves ◽  
Colonic Manometry

scholarly journals Intraluminal Prucalopride Increases Propulsive Motor Activities in the Human Colon

2020 ◽  
Author(s):  
Mitra Shokrollahi ◽  
Xuan-Yu Wang ◽  
Natalija Milkova ◽  
Jan D Huizinga ◽  
Ji-Hong Chen
Keyword(s):  
High Resolution ◽  
Motor Activity ◽  
Anal Sphincter ◽  
Human Colon ◽  
Delivery Systems ◽  
Enterochromaffin Cells ◽  
Temporal Association ◽  
Pressure Waves ◽  
Motor Patterns ◽  
Colonic Manometry

ABSTRACTBackgroundLuminal application of 5-HT4 receptor agonists can increase peristalsis in the guinea pig, mouse, rat and rabbit colon. Our aim in the present study was to test the effects of intraluminal prucalopride on motor patterns in the human colon.MethodsColonic motor patterns were studied in vivo in a healthy volunteer using High-Resolution Colonic Manometry (HRCM) with an 84-sensor water perfused catheter with 1cm spacing. 5-HT and 5-HT4 receptor immunohistochemistry was performed on human tissue biopsies throughout the colon.Key resultsActivating mucosal 5-HT4 receptors via intraluminal prucalopride enhanced propulsive motor activity in the human colon by increasing occurrence and amplitude of propulsive motor patterns including high-amplitude propagating pressure waves (HAPWs), pancolonic simultaneous pressure waves (SPWs) and HAPW-SPWs. Prucalopride-induced motor patterns had a close temporal association with a significant degree of anal sphincter relaxation and some were accompanied by a strong urge to defecate. Biopsies showed 100% colocalization of the 5-HT4 receptor to enterochromaffin cells throughout the colon and rectum.Conclusions and inferencesActivating luminal 5-HT4 receptors on enterochromaffin cells by intraluminal prucalopride increased propulsive motor activity. 5-HT4 receptors were found only on enterochromaffin cells and not ubiquitous on all epithelial cells. Our data support incorporation of prucalopride in colon-specific drug delivery systems as a prokinetic to treat colonic hypomotility disorders.50 word abstractHigh-resolution colonic manometry and biopsy immunohistochemistry revealed that 5-HT4 receptors in the lumen of the human colon are present exclusively on enterochromaffin cells and that the 5-HT4 agonist prucalopride evokes all major propulsive motor patterns, associated with significant anal sphincter relaxation, when given intraluminally.250-character clinical messageActivating luminal 5-HT4 receptors on enterochromaffin cells by intraluminal prucalopride increased propulsive motor activity in the human colon. Colon-specific delivery systems with a 5-HT4 agonist may become the preferred colon prokinetic.

scholarly journals Faecal incontinence is associated with an impaired rectosigmoid brake and improved by sacral neuromodulation

2021 ◽  
Author(s):  
Anthony Y Lin ◽  
Chris Varghese ◽  
Niranchan Paskaranandavadivel ◽  
Sean Seo ◽  
Peng Du ◽  
...  
Keyword(s):  
High Resolution ◽  
Mechanism Of Action ◽  
Faecal Incontinence ◽  
Sacral Neuromodulation ◽  
Colonic Motility ◽  
Distal Colon ◽  
Motor Patterns ◽  
Colonic Manometry ◽  
Stage 1 ◽  
Propagating Contractions

Background and aims: The rectosigmoid brake, characterized by retrograde cyclic motor patterns on high-resolution colonic manometry has been postulated as a contributor to the maintenance of bowel continence. Sacral neuromodulation (SNM) is an effective therapy for faecal incontinence, but its mechanism of action is unclear. This study aims to investigate the colonic motility patterns in the distal colon of patients with faecal incontinence, and how these are modulated by SNM. Methods: A high-resolution fibre-optic colonic manometry catheter, containing 36 sensors spaced at 1-cm intervals, was positioned in patients with faecal incontinence undergoing Stage 1 SNM. One hour of pre-meal and post-meal recordings were obtained followed by pre- and post-meal recordings with suprasensory SNM. A 700-kcal meal was given. Data were analysed to identify propagating contractions. Results: Fifteen patients with faecal incontinence were analysed. Patients had an abnormal meal response (fewer retrograde propagating contractions compared to controls; p=0.027) and failed to show a postmeal increase in propagating contractions (mean 17 +/- 6/h pre-meal vs 22 +/- 9/h post-meal, p = 0.438). Compared to baseline, SNM significantly increased the number of retrograde propagating contractions in the distal colon (8 +/- 3/h pre-meal vs 14 +/- 3/h pre-meal with SNM, p = 0.028). Consuming a meal did not further increase the number of propagating contractions beyond the baseline upregulating effect of SNM. Conclusion: The rectosigmoid brake was suppressed in this cohort of patients with faecal incontinence. SNM may exert a therapeutic effect by modulating this rectosigmoid brake.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

High-resolution electron microscopy of nanostructured materials

1995 ◽  
Vol 53 ◽  
pp. 172-173
Author(s):  
M. José-Yacamán
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Nanostructured Materials ◽  
High Resolution Electron Microscopy ◽  
Hrem Image ◽  
Small Particles ◽  
Resolution Electron ◽  
Nanophase Materials

Electron microscopy is a fundamental tool in materials characterization. In the case of nanostructured materials we are looking for features with a size in the nanometer range. Therefore often the conventional TEM techniques are not enough for characterization of nanophases. High Resolution Electron Microscopy (HREM), is a key technique in order to characterize those materials with a resolution of ~ 1.7A. High resolution studies of metallic nanostructured materials has been also reported in the literature. It is concluded that boundaries in nanophase materials are similar in structure to the regular grain boundaries. That work therefore did not confirm the early hipothesis on the field that grain boundaries in nanostructured materials have a special behavior. We will show in this paper that by a combination of HREM image processing, and image calculations, it is possible to prove that small particles and coalesced grains have a significant surface roughness, as well as large internal strain.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

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