scholarly journals Novel Bionics Assessment of Anorectal Mechanosensory Physiology

2020 ◽  
Vol 7 (4) ◽  
pp. 146
Author(s):  
Hans Gregersen
Keyword(s):  
Obstructed Defecation ◽  
Point Of View ◽  
Gi Tract ◽  
Physiological Variables ◽  
Experimental Approaches ◽  
Colon Transit ◽  
Large Animals ◽  
Cells Of Cajal ◽  
Shallow Waves ◽  
Shape Changes

Biomechatronics (bionics) is an applied science that creates interdisciplinary bonds between biology and engineering. The lower gastrointestinal (GI) tract is difficult to study but has gained interest in recent decades from a bionics point of view. Ingestible capsules that record physiological variables during GI transit have been developed and used for detailed analysis of colon transit and motility. Recently, a simulated stool named Fecobionics was developed. It has the consistency and shape of normal stool. Fecobionics records a variety of parameters including pressures, bending, and shape changes. It has been used to study defecation patterns in large animals and humans, including patients with symptoms of obstructed defecation and fecal incontinence. Recently, it was applied in a canine colon model where it revealed patterns consistent with shallow waves originating from slow waves generated by the interstitial Cells of Cajal. Novel analysis such as the “rear-front” pressure diagram and quantification of defecation indices has been developed for Fecobionics. GI research has traditionally been based on experimental approaches. Mathematical modeling is a unique way to deal with the complexity. This paper describes the Fecobionics technology, related mechano-physiological modeling analyses, and outlines perspectives for future applications.

scholarly journals Do GISTs Occur in Rats and Mice? Immunohistochemical Characterization of Gastrointestinal Tumors Diagnosed as Smooth Muscle Tumors in The National Toxicology Program

2019 ◽  
Vol 47 (5) ◽  
pp. 577-584
Author(s):  
Kyathanahalli S. Janardhan ◽  
Priyanka Venkannagari ◽  
Heather Jensen ◽  
Mark J. Hoenerhoff ◽  
Ronald A. Herbert ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cell Morphology ◽  
Spindle Cell ◽  
Smooth Muscle Actin ◽  
Gi Tract ◽  
Toxicological Studies ◽  
Smooth Muscle Tumors ◽  
Hematoxylin And Eosin ◽  
Cells Of Cajal ◽  
Rats And Mice

The majority of the tumors in the gastrointestinal (GI) tract of rats and mice, with spindle cell morphology, are diagnosed as smooth muscle tumors (SMTs). Similarly, several decades ago human GI tumors with spindle cell morphology were also diagnosed as SMTs. However, later investigations identified most of these tumors in humans as gastrointestinal stromal tumors (GISTs). The GISTs are considered to arise from the interstitial cells of Cajal located throughout the GI tract. Positive immunohistochemical staining with CKIT antibody is a well-accepted diagnostic marker for GISTs in humans. Since there is a considerable overlap between the histomorphology of SMTs and GISTs, it is not possible to distinguish them on hematoxylin and eosin stained sections. As a result, GISTs are not routinely diagnosed in toxicological studies. The current study was designed to evaluate the tumors diagnosed as leiomyoma or leiomyosarcoma in the National Toxicology Program’s 2-year bioassays using CKIT, smooth muscle actin, and desmin immunohistochemistry. The results demonstrate that most of the mouse SMTs diagnosed as leiomyoma or leiomyosarcoma are likely GISTs, whereas in rats the tumors are likely SMTs and not GISTs.

scholarly journals Liquid crystals of carbon nanotubes and graphene

2013 ◽  
Vol 371 (1988) ◽  
pp. 20120499 ◽  
Author(s):  
Cécile Zakri ◽  
Christophe Blanc ◽  
Eric Grelet ◽  
Camilo Zamora-Ledezma ◽  
Nicolas Puech ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Order Parameter ◽  
Orientational Order ◽  
Point Of View ◽  
General Point ◽  
Conductivity Anisotropy ◽  
Conductive Films ◽  
Experimental Approaches ◽  
New Methodologies

Liquid crystal ordering is an opportunity to develop novel materials and applications with spontaneously aligned nanotubes or graphene particles. Nevertheless, achieving high orientational order parameter and large monodomains remains a challenge. In addition, our restricted knowledge of the structure of the currently available materials is a limitation for fundamental studies and future applications. This paper presents recent methodologies that have been developed to achieve large monodomains of nematic liquid crystals. These allow quantification and increase of their order parameters. Nematic ordering provides an efficient way to prepare conductive films that exhibit anisotropic properties. In particular, it is shown how the electrical conductivity anisotropy increases with the order parameter of the nematic liquid crystal. The order parameter can be tuned by controlling the length and entanglement of the nanotubes. In the second part of the paper, recent results on graphene liquid crystals are reported. The possibility to obtain water-based liquid crystals stabilized by surfactant molecules is demonstrated. Structural and thermodynamic characterizations provide indirect but statistical information on the dimensions of the graphene flakes. From a general point of view, this work presents experimental approaches to optimize the use of nanocarbons as liquid crystals and provides new methodologies for the still challenging characterization of such materials.

Scope for growth versus actual growth in the juvenile predatory gastropod Chorus giganteus

2006 ◽  
Vol 86 (6) ◽  
pp. 1423-1428 ◽  
Author(s):  
J.M. Navarro ◽  
G.X. Urrutia ◽  
C. Carrasco
Keyword(s):  
Ingestion Rate ◽  
High Sensitivity ◽  
Point Of View ◽  
The Body ◽  
Experimental Conditions ◽  
Pronounced Increase ◽  
Continuous Increase ◽  
Scope For Growth ◽  
Physiological Variables ◽  
Actual Growth

The scope for growth (SFG) calculated on measurements of physiological variables in juvenile of the predatory gastropod Chorus giganteus was compared with the actual growth under an energetic point of view. The continuous increase in the amount of food ingested and absorbed by C. giganteus was clearly related to the body size of the snails. The pronounced increase in the metabolic processes of respiration and excretion at the end of the study was related with the high rates of growth experienced by the snails under the experimental conditions. These results were supported by the correlation analysis where ingestion rate (r=0.99), oxygen consumption (r=0.88) and excretion rate (r=0.89) were significantly correlated with the actual growth (P≤0.05). Comparing the estimated growth curve (SFG) with that directly measured on juvenile individuals of C. giganteus, a high similarity in results was observed. The high sensitivity of the scope for growth argues for the use of this index as an adequate tool for estimating the growth of juvenile gastropod molluscs without interference from reproductive processes such as gametogenesis and spawning which may produce corresponding rises and falls in the biomass of individuals. Scope for growth is thus validated as a reliable measurement of the physiological/energetic condition of the organism, representing an effective index for indirect estimation of the growth of a species.

Role of enterocele in the obstructed defecation syndrome (ODS): a new radiological point of view

2009 ◽  
Vol 12 (8) ◽  
pp. 810-816 ◽  
Author(s):  
C. Morandi ◽  
J. Martellucci ◽  
P. Talento ◽  
A. Carriero
Keyword(s):  
Obstructed Defecation ◽  
Point Of View ◽  
Obstructed Defecation Syndrome

scholarly journals Money Supply as the Target of the Central Bank

2014 ◽  
Vol 14 (1) ◽  
pp. 116-136
Author(s):  
Andrzej Jędruchniewicz
Keyword(s):  
Monetary Policy ◽  
Central Bank ◽  
Money Supply ◽  
Point Of View ◽  
Main Trend ◽  
Demand For Money ◽  
Intermediate Target ◽  
The Third ◽  
Production And Consumption ◽  
Shape Changes

Abstract The main purpose of the article is a critical analysis of the monetary policy strategy that is based on the adoption of money supply as an intermediate target. The analysis is conducted from the perspective of the theory of the Austrian school. The first part of the article presents an influence of the supply of money on changes of categories in economy according to mainstream theories of economics. The second part discusses the essence of the strategy of monetary policy using money supply as an intermediate target from the point of view of the main trend in economics. It is demonstrated that in order to use it, two elementary conditions must be met: the function of demand for money must be at least relatively stable and the central bank must practically shape changes in the money supply at the planned level. The third part is of key importance for the purpose of this article. It involves the criticism of Friedman’s principle, i.e. a constant increase in money supply as a monetary strategy. According to the Austrian theory, an increase in the quantity of money which is not financed by voluntary savings separates the time structure of production and consumption. Thus, after the period of prosperity there a collapse in production must take place. It is also pointed out that the crisis can be postponed only when the quantity of money increases at an ever faster rate.

I. Functional development and plasticity of interstitial cells of Cajal networks

2001 ◽  
Vol 281 (3) ◽  
pp. G602-G611 ◽  
Author(s):  
Sean M. Ward ◽  
Kenton M. Sanders
Keyword(s):  
Interstitial Cells Of Cajal ◽  
Interstitial Cells ◽  
Developmental Studies ◽  
Gi Tract ◽  
Functional Roles ◽  
Novel Studies ◽  
Downstream Signaling ◽  
Functional Development ◽  
Immunohistochemical Studies ◽  
Cells Of Cajal

Interstitial cells of Cajal (ICC) are the pacemaker cells in gastrointestinal (GI) muscles. They also mediate or transduce inputs from enteric motor nerves to the smooth muscle syncytium. What is known about functional roles of ICC comes from developmental studies based on the discovery that ICC express c- kit. Functional development of ICC networks depends on signaling via the Kit receptor pathway. Immunohistochemical studies using Kit antibodies have expanded our knowledge about the ICC phenotype, the structure of ICC networks, the interactions of ICC with other cells within the tunica muscularis, and the loss of ICC in some motility disorders. Manipulating Kit signaling with reagents to block the receptor or downstream signaling pathways or by using mutant mice in which Kit or its ligand, stem cell factor, are defective has allowed novel studies of the development of these cells within the tunica muscularisand also allowed the study of specific functions of different classes of ICC in several regions of the GI tract. This article examines the role of ICC in GI motility, focusing on the functional development and maintenance of ICC networks in the GI tract and the phenotypic changes that can occur when the Kit signaling pathway is disrupted.

Childhood obesity and eating behaviour

2015 ◽  
Vol 28 (5-6) ◽  
Author(s):  
Ana María Obregón ◽  
Paulina P. Pettinelli ◽  
Jose Luis Santos
Keyword(s):  
Childhood Obesity ◽  
Social Issues ◽  
Eating Behaviour ◽  
Recent Decade ◽  
Paediatric Population ◽  
High Energy ◽  
Point Of View ◽  
High Energy Density ◽  
Eating Rate ◽  
Physiological Variables

AbstractThe prevalence of childhood obesity has increased substantially in the recent decade as a result of the reduction in physical activity and the availability of high-fat and high-energy-density foods which the paediatric population faces daily. Although children are highly exposed to these foods, there is a wide variation in body weight, suggesting the presence of different patterns of response to an “obesogenic” environment. This wide variability from the point of view of eating behaviour involves a number of social issues (e.g., food availability, cost) as well as genuine behavioural traits such as the response to satiety, energy compensation, eating rate, responsiveness to food, food reward and dietary preferences. This article reviews the main physiological variables related to energy intake affecting eating behaviour in the paediatric population.

Role of Ano1 Ca2+-activated Cl− channels in generating urethral tone

2021 ◽  
Vol 320 (4) ◽  
pp. F525-F536
Author(s):  
Bernard T. Drumm ◽  
Keith D. Thornbury ◽  
Mark A. Hollywood ◽  
Gerard P. Sergeant
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Interstitial Cells Of Cajal ◽  
Muscle Cells ◽  
Interstitial Cells ◽  
Anoctamin 1 ◽  
Cl Channels ◽  
Experimental Approaches ◽  
Cells Of Cajal

Studies from rabbit show that anoctamin-1 (Ano1) channels expressed in urethral interstitial cells of Cajal (ICCs) serve as a source of depolarization for smooth muscle cells, increasing excitability and tone. However, the role of urethral Ano1 channels is unclear, owing to differences in the species examined and experimental approaches. We summarize findings from different species on the role of urethral ICC and Ano1 channels in urethral contractility and outline proposals for clarifying this topic using cell-specific optogenetic approaches.

Interstitial cells of Cajal mediate nitrergic inhibitory neurotransmission in the murine gastrointestinal tract

2014 ◽  
Vol 307 (1) ◽  
pp. G98-G106 ◽  
Author(s):  
Barbara Lies ◽  
Víctor Gil ◽  
Dieter Groneberg ◽  
Barbara Seidler ◽  
Dieter Saur ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Interstitial Cells Of Cajal ◽  
Cell Types ◽  
Interstitial Cells ◽  
Gi Tract ◽  
Inhibitory Neurotransmitter ◽  
Inhibitory Junction Potential ◽  
Cells Of Cajal ◽  
Junction Potential

Nitric oxide (NO) is a major inhibitory neurotransmitter in the gastrointestinal (GI) tract. Its main effector, NO-sensitive guanylyl cyclase (NO-GC), is expressed in several GI cell types, including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), and fibroblast-like cells. Up to date, the interplay between neurons and these cells to initiate a nitrergic inhibitory junction potential (IJP) is unclear. Here, we investigate the origin of the nitrergic IJP in murine fundus and colon. IJPs were determined in fundus and colon SMC of mice lacking NO-GC globally (GCKO) and specifically in SMC (SM-GCKO), ICC (ICC-GCKO), and both SMC/ICC (SM/ICC-GCKO). Nitrergic IJP was abolished in ICC-GCKO fundus and reduced in SM-GCKO fundus. In the colon, the amplitude of nitrergic IJP was reduced in ICC-GCKO, whereas nitrergic IJP in SM-GCKO was reduced in duration. These results were corroborated by loss of the nitrergic IJP in global GCKO. In conclusion, our results prove the obligatory role of NO-GC in ICC for the initiation of an IJP. NO-GC in SMC appears to enhance the nitrergic IJP, resulting in a stronger and prolonged hyperpolarization in fundus and colon SMC, respectively. Thus NO-GC in both cell types is mandatory to induce a full nitrergic IJP. Our data from the colon clearly reveal the nitrergic IJP to be biphasic, resulting from individual inputs of ICC and SMC.

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