scholarly journals Cardiac Mechano-Electric Coupling: Acute Effects of Mechanical Stimulation on Heart Rate and Rhythm

2021 ◽  
Vol 101 (1) ◽  
pp. 37-92 ◽  
Author(s):  
T. Alexander Quinn ◽  
Peter Kohl

The heart is vital for biological function in almost all chordates, including humans. It beats continually throughout our life, supplying the body with oxygen and nutrients while removing waste products. If it stops, so does life. The heartbeat involves precise coordination of the activity of billions of individual cells, as well as their swift and well-coordinated adaption to changes in physiological demand. Much of the vital control of cardiac function occurs at the level of individual cardiac muscle cells, including acute beat-by-beat feedback from the local mechanical environment to electrical activity (as opposed to longer term changes in gene expression and functional or structural remodeling). This process is known as mechano-electric coupling (MEC). In the current review, we present evidence for, and implications of, MEC in health and disease in human; summarize our understanding of MEC effects gained from whole animal, organ, tissue, and cell studies; identify potential molecular mediators of MEC responses; and demonstrate the power of computational modeling in developing a more comprehensive understanding of ‟what makes the heart tick.ˮ

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Andreea Milasan ◽  
Nicolas Tessandier ◽  
Sisareuth Tan ◽  
Alain Brisson ◽  
Eric Boilard ◽  
...  

Introduction: Although for a long time considered as simple cellular debris, extracellular vesicles (EVs) are now known to be involved in many pathophysiological processes such as thrombosis, autoimmune diseases and inflammation. Due to their diversity and presence in different tissues, EVs are considered important biomarkers and thus, their precise detection in various biological fluids is important to better understand all their different functional activities. The lymphatic system works in close collaboration with the cardiovascular system to preserve fluid balance throughout the body. Lymphatic vessels are present in almost all vascularized tissues, including the brain and the artery wall, and their role in these organ-related pathologies are under intense investigations. Hypothesis: Since lymphatic vessels are often perceived as "sewers", due to their role in removing interstitial fluid and waste products from peripheral tissues such as the artery wall, we herein want to qualitatively and quantitatively assess the presence of EVs in circulating lymph. Methods and Results: Using several approaches such as a Zetasizer Nano S, electron microscopy and flow cytometry analysis, we have detected and characterized EVs in lymph of healthy animals, and found that these EVs are inclusively derived from red blood cells, platelets and lymphatic endothelial cells. Analysis of lymph from atherosclerotic mice (Ldlr -/- ) confirmed the idea that EVs number and origin varies according to the pathological setting. Conclusion: Herein, we show for the first time that EVs are present in lymph and that their level and origin vary in atherosclerosis. Our work will be setting the stage to a better understanding of the mechanism underlying EV accumulation in peripheral tissues during inflammation, and to better control related diseases.


AYUSHDHARA ◽  
2020 ◽  
pp. 64-68
Author(s):  
Pretty P

Ayurveda imparts a great emphasis upon the maintenance of positive health of a person. According to WHO, health is a complete state of physical, mental, social, spiritual well being and not merely the absence of disease. Sushruthas quotation regarding Swastha is exactly same which was told many decades back. Healthy body is the outcome of healthy food and lifestyle and it is the basis for health and disease. Nutrient rich diet which is consumed in proper time and amount will help the body which contributes it to maintain the homeostasis. Food has to be properly digested for the nourishment and formation of healthy Dhathu. Digestion takes place in Mahakoshta and as a result of this, food is converted into Prasadamsa and Kittamsa. Dhatus are formed in a series from Rasa to Shukra from this Prasada portion. Dhatus after their Dhatuagni paka is divided into Sara and Kitta bhaga, and from this Kitta bhaga dhatu malas are formed. Malas represent a wide variety of substances produced by the body through different Pakas conducted in the body. Removal of metabolites and waste products are the basic physiological functions of body. Mala are the waste products that need to be eliminated from the body periodically. Scope of the experiment: Here in this article the physiological interpretation of Dhatumala and its need to be flushed out on regular basis is explained. Physiological view point of Dhathumala will help to understand what it is and how it is formed in the body in a better way to the present generation.


1972 ◽  
Vol 18 (4) ◽  
pp. 320-329 ◽  
Author(s):  
D N Baron

Abstract The plasma compartment, on which almost all routine analyses in clinical chemistry are performed, occupies only a small part of the body, most of which consists of cells. For most components the intracellular and extracellular compartments have a different composition in health, and change differently in disease. The readily available cells are erythrocytes, and although these can be used for many purposes, including vitamin studies, they should not be used for studies of water and electrolytes. Muscle cells and leukocytes are the other available cells: they present different problems of isolation and methodology, but valid work has been done on their use for studies of water, electrolytes, and pH in health and disease. A recently developing study is the identification of inborn errors of metabolism by analysis of leukocytes and other cells. All cellular studies offer problems in that changes in one type of cell cannot necessarily be applied to changes in the cellular compartment of the body as a whole.


Author(s):  
L. Yarmots ◽  
G. Yarmots ◽  
A. Belenkaya

For ruminants, especially high-yielding animals in addition to the complete supply of animals with protein, its digestibility in the rumen is important. With low protein digestibility in the rumen, the released ammonia will be more effectively used by the rumen microflora, and the undigestible protein in the subsequent sections of the digestive tract can serve as a source of amino acids for the body. The use of concentrate mixtures with the inclusion of local, affordable and cheaper grain feeds, in particular a high-energy and protein ingredient- rapeseed presscake makes it possible to increase the milk productivity of cows throughout lactation. These presscakes are well balanced in their amino acid composition and belong to feeds whose protein has a low degree of digestibility in the rumen. The purpose of the researches was to study the digestibility of nutrients and milk productivity of cows when using the concentrate mixture with the inclusion of rapeseed presscake. In the scientific and economic experiment has been carried out on lactating cows, where the cows of the experimental group in the concentrate mixture of peas has been replaced with rapeseed presscake the digestibility of nutrients in the ration, energy metabolism and milk productivity have been studied. Studies have shown that almost all the nutrients were significantly better digested by the animals of the experimental group. Energy in milk was more allocated by cows of the experimental group by 6,29 MJ. From cows of the experimental group for 100 and 305 days of lactation has been obtained more milk by 6,27 and 7,06 %, respectively, than from control herdmates. The biochemical parameters of blood were within the limits of the physiological norm in animals of both groups. Thus, the replacement of peas with rapeseed presscake in the concentrate mixture did not have a negative influence on the metabolic processes and helped to increase the milk productivity of cows.


2020 ◽  
Vol 27 (29) ◽  
pp. 4840-4854 ◽  
Author(s):  
Chrysoula-Evangelia Karachaliou ◽  
Hubert Kalbacher ◽  
Wolfgang Voelter ◽  
Ourania E. Tsitsilonis ◽  
Evangelia Livaniou

Prothymosin alpha (ProTα) is a highly acidic polypeptide, ubiquitously expressed in almost all mammalian cells and tissues and consisting of 109 amino acids in humans. ProTα is known to act both, intracellularly, as an anti-apoptotic and proliferation mediator, and extracellularly, as a biologic response modifier mediating immune responses similar to molecules termed as “alarmins”. Antibodies and immunochemical techniques for ProTα have played a leading role in the investigation of the biological role of ProTα, several aspects of which still remain unknown and contributed to unraveling the diagnostic and therapeutic potential of the polypeptide. This review deals with the so far reported antibodies along with the related immunodetection methodology for ProTα (immunoassays as well as immunohistochemical, immunocytological, immunoblotting, and immunoprecipitation techniques) and its application to biological samples of interest (tissue extracts and sections, cells, cell lysates and cell culture supernatants, body fluids), in health and disease states. In this context, literature information is critically discussed, and some concluding remarks are presented.


Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 289
Author(s):  
Adamasco Cupisti ◽  
Piergiorgio Bolasco ◽  
Claudia D’Alessandro ◽  
Domenico Giannese ◽  
Alice Sabatino ◽  
...  

The retention of uremic toxins and their pathological effects occurs in the advanced phases of chronic kidney disease (CKD), mainly in stage 5, when the implementation of conventional thrice-weekly hemodialysis is the prevalent and life-saving treatment. However, the start of hemodialysis is associated with both an acceleration of the loss of residual kidney function (RKF) and the shift to an increased intake of proteins, which are precursors of uremic toxins. In this phase, hemodialysis treatment is the only way to remove toxins from the body, but it can be largely inefficient in the case of high molecular weight and/or protein-bound molecules. Instead, even very low levels of RKF are crucial for uremic toxins excretion, which in most cases are protein-derived waste products generated by the intestinal microbiota. Protection of RKF can be obtained even in patients with end-stage kidney disease (ESKD) by a gradual and soft shift to kidney replacement therapy (KRT), for example by combining a once-a-week hemodialysis program with a low or very low-protein diet on the extra-dialysis days. This approach could represent a tailored strategy aimed at limiting the retention of both inorganic and organic toxins. In this paper, we discuss the combination of upstream (i.e., reduced production) and downstream (i.e., increased removal) strategies to reduce the concentration of uremic toxins in patients with ESKD during the transition phase from pure conservative management to full hemodialysis treatment.


2013 ◽  
Vol 69 (11) ◽  
pp. 2287-2292 ◽  
Author(s):  
Andrew C. Kruse ◽  
Aashish Manglik ◽  
Brian K. Kobilka ◽  
William I. Weis

G protein-coupled receptors (GPCRs) are a large class of integral membrane proteins involved in regulating virtually every aspect of human physiology. Despite their profound importance in human health and disease, structural information regarding GPCRs has been extremely limited until recently. With the advent of a variety of new biochemical and crystallographic techniques, the structural biology of GPCRs has advanced rapidly, offering key molecular insights into GPCR activation and signal transduction. To date, almost all GPCR structures have been solved using molecular-replacement techniques. Here, the unique aspects of molecular replacement as applied to individual GPCRs and to signaling complexes of these important proteins are discussed.


Author(s):  
Adenike Adegbayi

Abstract The aim of the study is to add to the body of knowledge on less researched aspects of female adolescent health in Nigeria. It specifically explored the menarche or first period narratives of 136 young women, focusing on the contents of the discussion that ensued with whom they told when they first got their period using qualitative methodology. It also explores sources of premenstrual information and how the menstrual period is managed. The sample consisted of 136 undergraduate females in Redeemer’s University, Ede, Nigeria. Almost all of the respondents (95%) received information about menstruation from mothers, female relatives and school lessons prior to menarche. The majority of the respondents first told either their mother or a female relative when they first got their period and viewed menarche as a crisis. Two salient themes emerged from the contents of the narratives; celebration and advice. The advice theme was further explored and three advice patterns were identified: being a woman, hygiene and changed dynamics in relationships with males. Data from the present study suggests that only certain aspects of the menstruation discourse have evolved. All respondents reported using sanitary towels during their menstrual period with the majority experiencing cramps regularly and (61%) using pharmalogical agents for remedy. It is envisaged that findings from the study will be useful in future health intervention programmes and research on female adolescent health in Nigeria and elsewhere.


Author(s):  
Vincent Geenen

AbstractThe conventional perception asserts that immunology is the science of ‘discrimination’ between self and non-self. This concept is however no longer tenable as effector cells of the adaptive immune system are first conditioned to be tolerant to the body’s own antigens, collectively known as self until now. Only then attain these effectors the responsiveness to non-self. The acquisition of this essential state of tolerance to self occurs for T cells in the thymus, the last major organ of our body that revealed its intricate function in health and disease. The ‘thymus’ as an anatomical notion was first notably documented in Ancient Greece although our present understanding of the organ’s functions was only deciphered commencing in the 1960s. In the late 1980s, the thymus was identified as the site where clones of cells reactive to self, termed ‘forbidden’ thymocytes, are physically depleted as the result of a process now known as negative selection. The recognition of this mechanism further contributed to the belief that the central rationale of immunology as a science lies in the distinction between self and non-self. This review will discuss the evidence that the thymus serves as a unique lymphoid organ able to instruct T cells to recognize and be tolerant to harmless self before adopting the capacity to defend the body against potentially injurious non-self-antigens presented in the context of different challenges from infections to exposure to malignant cells. The emerging insight into the thymus’ cardinal functions now also provides an opportunity to exploit this knowledge to develop novel strategies that specifically prevent or even treat organ-specific autoimmune diseases.


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