scholarly journals Seeing the Light: The Use of Zebrafish for Optogenetic Studies of the Heart

2021 ◽  
Vol 12 ◽  
Author(s):  
Jonathan S. Baillie ◽  
Matthew R. Stoyek ◽  
T. Alexander Quinn
Keyword(s):  
Experimental Model ◽  
Optical Measurement ◽  
Cardiac Activity ◽  
Experimental Models ◽  
Spatially Resolved ◽  
And Control ◽  
Spatiotemporal Control ◽  
Insight Into

Optogenetics, involving the optical measurement and manipulation of cellular activity with genetically encoded light-sensitive proteins (“reporters” and “actuators”), is a powerful experimental technique for probing (patho-)physiological function. Originally developed as a tool for neuroscience, it has now been utilized in cardiac research for over a decade, providing novel insight into the electrophysiology of the healthy and diseased heart. Among the pioneering cardiac applications of optogenetic actuators were studies in zebrafish, which first demonstrated their use for precise spatiotemporal control of cardiac activity. Zebrafish were also adopted early as an experimental model for the use of optogenetic reporters, including genetically encoded voltage- and calcium-sensitive indicators. Beyond optogenetic studies, zebrafish are becoming an increasingly important tool for cardiac research, as they combine many of the advantages of integrative and reduced experimental models. The zebrafish has striking genetic and functional cardiac similarities to that of mammals, its genome is fully sequenced and can be modified using standard techniques, it has been used to recapitulate a variety of cardiac diseases, and it allows for high-throughput investigations. For optogenetic studies, zebrafish provide additional advantages, as the whole zebrafish heart can be visualized and interrogated in vivo in the transparent, externally developing embryo, and the relatively small adult heart allows for in situ cell-specific observation and control not possible in mammals. With the advent of increasingly sophisticated fluorescence imaging approaches and methods for spatially-resolved light stimulation in the heart, the zebrafish represents an experimental model with unrealized potential for cardiac optogenetic studies. In this review we summarize the use of zebrafish for optogenetic investigations in the heart, highlighting their specific advantages and limitations, and their potential for future cardiac research.

scholarly journals Kairiojo plaučio transplantacija žiurkei: eksperimentinio modelio paieškos

2006 ◽  
Vol 4 (3) ◽  
pp. 0-0
Author(s):  
Remigijus Sipavičius ◽  
Aleksejus Zorinas ◽  
Dalia Drobelytė ◽  
Rokas Šerpytis ◽  
Vytautas Sirvydis
Keyword(s):  
Lung Transplantation ◽  
Experimental Model ◽  
Heart Surgery ◽  
Left Lung ◽  
Experimental Models ◽  
Bronchial Anastomosis ◽  
G 21 ◽  
Vilnius University ◽  
Anesthetic Overdosage

Remigijus Sipavičius1, Aleksejus Zorinas1, Dalia Drobelytė2, Rokas Šerpytis2, Vytautas Sirvydis1.1 Vilniaus universiteto Širdies ir kraujagyslių ligų klinikos Širdies chirurgijos centras,Santariškių g. 2, LT-08661 Vilnius2 Vilniaus universiteto Medicinos fakultetas,M. K. Čiurlionio g. 21, LT-03101 VilniusEl. paštas: [email protected] Tikslas Sukurti ar pritaikyti esamus eksperimentinius modelius žiurkėms, tęsiant tyrinėjimus plaučių transplantacijos srityje. Metodai Žiurkėms atliekama kairiojo plaučio autotransplantacija arba ortotopinė transplantacija. Autotransplantacijos atveju atliekama kairiojo plaučio pulmoplegija, plautis paliekamas vietoje konservacijai norimam išemijos laikui. Jam praėjus atkuriama plaučio kraujotaka. Transplantacijos atveju donorui atliekama abiejų plaučių pulmoplegija, jie konservuojami norimą išemijos laiką. Recipientui pašalinamas kairysis plautis. Praėjus išemijos laikui, donoro kairysis plautis persodinamas recipientui, atkuriama plaučio kraujotaka. Rezultatai Atlikta 11 eksperimentų, penki iš jų – sėkmingai. Pagrindinės nesėkmių priežastys buvo broncho ar jo anastomozės plyšimas bei anestetikų perdozavimas. Išvados Esamus eksperimentinius modelius pavyko adaptuoti žiurkėms. Jie taikytini tolesnems plaučių transplantacijos tyrinėjimams. Pagrindiniai žodžiai: plaučių transplantacija, eksperimentinis modelis Left lung transplantation in rat: search for the experimental model Remigijus Sipavičius1, Aleksejus Zorinas1, Dalia Drobelytė2, Rokas Šerpytis2, Vytautas Sirvydis1.1 Vilnius University Clinic of Cardiovascular Diseases, Heart Surgery Centre,Santariškių str. 2, LT-08661 Vilnius, Lithuania2 Vilnius University Faculty of Medicine,M. K. Čiurlionio str. 21, LT-03101 Vilnius, LithuaniaE-mail: [email protected] Objective To design a new or to adapt the existing experimental models of rat lung transplantation. Methods Both left lung autotransplantation and orthotopic transplantation are implemented in rat. At autotransplantation, the left lung is left in situ after pulmoplegia. After a settled ischaemic time the lung perfusion is restored. At transplantation, pulmoplegia is performed in the donor. Lungs are separated and preserved for a settled ischaemic time. The recipient's left lung is removed and the donor's left lung transplantation is performed. The graft's perfusion is restored. Results Eleven experiments were carried out, 5 of them successfully. The main reasons for failure were bronchial anastomosis dehiscence or bronchial tear and anesthetic overdosage. Conclusion Existing experimental models were successfully adapted in rat, capacitating the further lung transplantation research. Key words: lung transplantation, experimental model

Intervertebral Disc Residual and Equilibrium Viscoelastic Parameters Specific to Location and Degeneration Severity

2010 ◽  
Author(s):  
A. M. Ellingson ◽  
D. J. Nuckley
Keyword(s):  
Residual Stress ◽  
Low Back Pain ◽  
Back Pain ◽  
Intervertebral Disc ◽  
Low Back ◽  
Viscoelastic Parameters ◽  
Viscoelastic Modeling ◽  
Insight Into

Chronic low back pain affects an estimated 15–65% of the U.S. population. Disc degeneration is often accredited as the origin of low back pain. With degeneration comes the breakdown of proteoglycans, loss of water content, and a decrease in the height of the intervertebral disc (IVD). These changes likely affect the disc’s viscoelastic response, making modeling and subsequent prediction of degeneration mechanics difficult. Unfortunately, much of the previous mechanical testing of IVD tissues has involved excision of the tissue and disruption of annular fibers. To gain insight into the in situ viscoelastic material properties, we have developed a new methodology of hybrid confined / in situ compression. This technique also allows for the quantification of the residual stress and strain that the IVD experiences in vivo and improved viscoelastic modeling parameters. Residual measurements, to the knowledge of the authors, have yet to be reported in previous studies. Therefore, the purpose of this study was to define the viscoelastic properties of the intact intervertebral disc as well as the residual stress/strain specific to degeneration grade and location.

Advances in imaging feto-placental vasculature: new tools to elucidate the early life origins of health and disease

2020 ◽  
pp. 1-11
Author(s):  
Yutthapong Tongpob ◽  
Caitlin Wyrwoll
Keyword(s):  
Ex Vivo ◽  
Light Sheet ◽  
Experimental Models ◽  
Cardiovascular Development ◽  
Micro Computed Tomography ◽  
Placental Function ◽  
Light Sheet Microscopy ◽  
Health And Disease ◽  
Insight Into

Abstract Optimal placental function is critical for fetal development, and therefore a crucial consideration for understanding the developmental origins of health and disease (DOHaD). The structure of the fetal side of the placental vasculature is an important determinant of fetal growth and cardiovascular development. There are several imaging modalities for assessing feto-placental structure including stereology, electron microscopy, confocal microscopy, micro-computed tomography, light-sheet microscopy, ultrasonography and magnetic resonance imaging. In this review, we present current methodologies for imaging feto-placental vasculature morphology ex vivo and in vivo in human and experimental models, their advantages and limitations and how these provide insight into placental function and fetal outcomes. These imaging approaches add important perspective to our understanding of placental biology and have potential to be new tools to elucidate a deeper understanding of DOHaD.

Assessment of airway response distribution and paradoxical airway dilation in mice during methacholine challenge

2017 ◽  
Vol 122 (3) ◽  
pp. 503-510 ◽  
Author(s):  
S. Dubsky ◽  
G. R. Zosky ◽  
K. Perks ◽  
C. R. Samarage ◽  
Y. Henon ◽  
...  
Keyword(s):  
Dynamic Imaging ◽  
Lung Mechanics ◽  
Imaging Method ◽  
Response Distribution ◽  
Interconnected System ◽  
Airway Response ◽  
Airway Responses ◽  
And Control

Detailed information on the distribution of airway diameters during bronchoconstriction in situ is required to understand the regional response of the lungs. Imaging studies using computed tomography (CT) have previously measured airway diameters and changes in response to bronchoconstricting agents, but the manual measurements used have severely limited the number of airways measured per subject. Hence, the detailed distribution and heterogeneity of airway responses are unknown. We have developed and applied dynamic imaging and advanced image-processing methods to quantify and compare hundreds of airways in vivo. The method, based on CT, was applied to house dust-mite-sensitized and control mice during intravenous methacholine (MCh) infusion. Airway diameters were measured pre- and post-MCh challenge, and the results compared demonstrate the distribution of airway response throughout the lungs during mechanical ventilation. Forced oscillation testing was used to measure the global response in lung mechanics. We found marked heterogeneity in the response, with paradoxical dilation of airways present at all airway sizes. The probability of paradoxical dilation decreased with decreasing baseline airway diameter and was not affected by pre-existing inflammation. The results confirm the importance of considering the lung as an entire interconnected system rather than a collection of independent units. It is hoped that the response distribution measurements can help to elucidate the mechanisms that lead to heterogeneous airway response in vivo. NEW & NOTEWORTHY Information on the distribution of airway diameters during bronchoconstriction in situ is critical for understanding the regional response of the lungs. We have developed an imaging method to quantify and compare the size of hundreds of airways in vivo during bronchoconstriction in mice. The results demonstrate large heterogeneity with both constriction and paradoxical dilation of airways, confirming the importance of considering the lung as an interconnected system rather than a collection of independent units.

The Development of an In Situ Assay for bFGF Release

1993 ◽  
Vol 331 ◽  
Author(s):  
S. K. Hobbs ◽  
L. M. Periolat ◽  
L. G. Cima ◽  
M. Nugent ◽  
M. Leunig ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Dorsal Skinfold Chamber ◽  
Control Growth ◽  
Vessel Growth ◽  
And Control ◽  
Tissue Reactivity ◽  
In Situ Assay

AbstractThere is a need for an in situ assay to quantify tissue reactivity to sustained release of bFGF to better understand and control growth factor-induced angiogenesis. To this end we have adapted the alginate/heparin-sepharose release system for use in the mouse dorsal skinfold chamber. A mathematical model was used to predict the time dependence of bFGF release as a function of bFGF loading, heparin concentration, and device geometry. The model predictions agreed well with previously reported in vitro data. In vivo studies to correlate blood vessel growth as a function of release rate are in progress.

Repression of protein synthesis and mTOR signaling in rat liver mediated by the AMPK activator aminoimidazole carboxamide ribonucleoside

2005 ◽  
Vol 288 (5) ◽  
pp. E980-E988 ◽  
Author(s):  
Ali K. Reiter ◽  
Douglas R. Bolster ◽  
Stephen J. Crozier ◽  
Scot R. Kimball ◽  
Leonard S. Jefferson
Keyword(s):  
Protein Synthesis ◽  
Rat Liver ◽  
Translational Control ◽  
Serum Insulin ◽  
Experimental Models ◽  
Mtor Signaling ◽  
Initiation Factor ◽  
Perfused Liver

The studies described herein were designed to investigate the effects of 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleoside (AICAR), an activator of the AMP-activated protein kinase (AMPK), on the translational control of protein synthesis and signaling through the mammalian target of rapamycin (mTOR) in rat liver. Effects of AICAR observed in vivo were compared with those obtained in an in situ perfused liver preparation to investigate activation of AMPK in the absence of accompanying changes in hormones and nutrients. AMPK became hyperphosphorylated, as assessed by a gel-shift analysis, in response to AICAR both in vivo and in situ; however, increased relative phosphorylation at the Thr172 site on the kinase was observed only in perfused liver. Phosphorylation of AMPK either in vivo or in situ was associated with a repression of protein synthesis as well as decreased phosphorylation of a number of targets of mTOR signaling including ribosomal protein S6 kinase 1, eukaryotic initiation factor (eIF)4G, and eIF4E-binding protein (4E-BP)1. The phosphorylation changes in eIF4G and 4E-BP1 were accompanied by a reduction in the amount of eIF4E present in the active eIF4E·eIF4G complex and an increase in the amount present in the inactive eIF4E·4E-BP1 complex. Reduced insulin signaling as well as differences in nutrient availability may have contributed to the effects observed in vivo as AICAR caused a fall in the serum insulin concentration. Overall, however, the results from both experimental models support a scenario in which AICAR directly represses protein synthesis and mTOR signaling in the liver through an AMPK-dependent mechanism.

scholarly journals Экспериментальные модели сократительной активности миометрия

2020 ◽  
Author(s):  
A.A. Yakovleva ◽  
N.G. Pavlova
Keyword(s):  
In Silico ◽  
Contractile Activity ◽  
Experimental Models ◽  
Pacemaker Activity ◽  
Single View ◽  
Uterine Contractile ◽  
Experimental Approaches

Сократительная деятельность матки до настоящего времени остается актуальным вопросом фундаментальных исследований, поскольку отсутствуют единые представления о биомеханике маточного сокращения, необходимые для профилактики родового и акушерского травматизма. Цель работы - оценка ограничений и возможностей экспериментальных моделей, предназначенных для изучения сократительной активности миометрия. Методика. Основными экспериментальными подходами к изучению сократительной активности матки являлись исследования in vitro, in situ, in vivo, in silico, а также их сочетание. Результаты. В статье рассмотрены исследования, в которых использованы различные сочетания экспериментальных подходов, обсуждаются результаты, полученные при моделировании в экспериментах, обсуждаются результаты изучения синхронизации сокращения отделов матки на различных моделях, а также результаты исследования пейсмейкерной активности миометрия и возможность экстраполяции полученных данных на человека. В связи с активным развитием компьютерных технологий в статье поднимается вопрос об их использовании в моделировании сократительной активности матки человека. Заключение. Делается заключение, что комплексный подход, включающий электромиографические, биохимические и морфологические исследования в хроническом эксперименте, является наиболее адекватным для изучения сократительной активности миометрия и функционального состояния нормально развитых и отставших в развитии плодов, что позволит разработать комплексные методы профилактики родового и акушерского травматизма.Uterine contractile activity remains an important issue of fundamental research as there is no single view of the biomechanics of uterine contraction necessary for the prevention of parturition and obstetric trauma until now. The aim of the review was to assess advantages and limitations of experimental models described in the literature for study uterine contractile activity. At the present time main experimental approaches for study myometrium contractile activity are research in vitro, in situ, in vivo, in silico and the their combinations. The literature presents experimental approaches, different models of uterine contractions synchronization and study of myometrium pacemaker activity. Due to active development of computer technologies there is a need to model human uterine contractile activity with a simplified anatomy. The authors propose that combination of electromyographic, biochemical and morphological methods in chronic experiment is the most correct and appropriate direction for the assessment of the myometrium contractile activity and functional state of normally developed and growth restricted fetuses.

scholarly journals The investigation of adaptogenic and hepatoprotective properties of Ilex paraguariensis on experimental models in vivo

2021 ◽  
pp. 43-51
Author(s):  
Aksana I. Hubich ◽  
Svyatlana S. Okarakava ◽  
Darya V. Kopyleva ◽  
Nadezhda S. Jaafar ◽  
Dziyana V. Duts ◽  
...  
Keyword(s):  
Physical Activity ◽  
Experimental Model ◽  
Alcohol Intoxication ◽  
Energy Drink ◽  
Experimental Models ◽  
Ilex Paraguariensis ◽  
Chlorogenic Acids ◽  
Silybum Marianum ◽  
Chronic Alcohol Intoxication

This work is devoted to the study of the effect of Ilex paraguariensis decoction for energy and carbohydrate metabolism in conditions of increased physical activity, the analysis of the stabilisation possibilities of liver injury and lipid peroxidation markers in rats in an experimental model of chronic alcohol intoxication. It’s established that I. paraguariensis exhibits antioxidant and hepatoprotective effects in rats with experimental alcoholic liver, comparable to the action of classical plant hepatoprotector – Silybum marianum, has a stimulating and adaptogenic effects in experimental model of physical activity, comparable to the energy drink «Wild Jaguar». The results obtained may be due to the presence of flavonoids, ascorbic and chlorogenic acids, exhibiting an antioxidant effect, as well as caffeine, which is known to stimulate the work of the central nervous and cardiovascular systems.

Augmented bidirectional HCO3 transport by rat distal tubules in chronic alkalosis

1991 ◽  
Vol 261 (2) ◽  
pp. F308-F317 ◽  
Author(s):  
D. E. Wesson ◽  
G. M. Dolson
Keyword(s):  
Metabolic Alkalosis ◽  
Distal Tubule ◽  
Free Flow ◽  
Proton Secretion ◽  
Nephron Segment ◽  
Distal Tubules ◽  
And Control

Free-flow micropuncture studies show both augmented net HCO3 reabsorption in the distal tubule of rats with chronic metabolic alkalosis and higher HCO3 delivery to this nephron segment. The present studies in rats used in vivo microperfusion of surface distal tubules to investigate whether the augmented net reabsorption 1) was due to decreased HCO3 secretion and/or to increased proton secretion or 2) depended on the higher HCO3 delivery to the distal tubule. Artificial perfusates were designed to simulate in situ deliveries of HCO3 to the distal tubules of both alkalotic and control animals and to represent extremes of in situ Cl deliveries. Rather than being decreased, both measured and calculated HCO3 secretion were higher in the alkalotic animals for each perfusate used. Similarly, calculated proton secretion (difference between net HCO3 reabsorption and calculated HCO3 secretion) was higher for the alkalotic animals using each HCO3-containing perfusate. Augmented net HCO3 reabsorption by alkalotic animals was more clearly demonstrated using higher HCO3 deliveries and Cl-free perfusates. These studies demonstrate that both the reabsorptive and secretory components of net HCO3 transport are increased in the distal tubule of animals with chronic metabolic alkalosis.

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