Validation of a New Micro-Manometer Pressure Sensor for Cardiovascular Measurements in Mice

Abstract The Scisense (London, ON, Canada) micro-manometer pressure sensor is currently being used by investigators to evaluate cardiovascular physiology in mice, but has not been validated to date. The purpose of the current study is to compare the 1.2 F Scisense pressure sensor to the current gold standard produced by Millar Instruments (Houston, TX) (1.4 F). In vitro comparisons were preformed including temperature drift, frequency response analysis up to 250 Hz, and damping coefficient and natural frequency determined via a pop test. The authors also performed in vivo comparisons including pressure drift, dose-response studies to IV isoproterenol, maximum adrenergic stimulation with IV dobutamine, and simultaneous placement of both micro-manometer pressure sensors in the same intact murine hearts. The authors conclude that both sensors are equivalent, and that the Scisense pressure sensor represents an alternative to the current gold standard, the Millar micro-manometer pressure sensor for in vivo pressure measurements in the mouse

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β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

Thrombosis and Haemostasis ◽

10.1160/th14-01-0059 ◽

2014 ◽

Vol 112 (11) ◽

pp. 951-959 ◽

Cited By ~ 1

Author(s):

Morten Eriksen ◽

Arnfinn Ilebekk ◽

Alessandro Cataliotti ◽

Cathrine Rein Carlson ◽

Torstein Lyberg ◽

...

Keyword(s):

Adrenergic Receptor ◽

Sympathetic Nerves ◽

Ventricular Myocardium ◽

Left Ventricular ◽

Left Ventricular Myocardium ◽

Adrenergic Stimulation ◽

Β2 Adrenergic Receptor ◽

Β Blocker

SummaryBradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and nonstimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

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Micromachined Pressure Sensors on Optical Fiber Tip

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.74.149 ◽

2009 ◽

Vol 74 ◽

pp. 149-152

Author(s):

X.M. Zhang ◽

M. Yu ◽

Silas Nesson ◽

H. Bae ◽

A. Christian ◽

...

Keyword(s):

Optical Fiber ◽

Pressure Sensor ◽

Linear Response ◽

Applied Pressure ◽

Pressure Sensors ◽

Outer Diameter ◽

Sensor Element ◽

Batch Fabrication ◽

In Vitro Measurements

This paper reports the development of a miniature pressure sensor on the optical fiber tip for in vitro measurements of rodent intradiscal pressure. The sensor element is biocompatible and can be fabricated by simple, batch-fabrication methods in a non-cleanroom environment with good device-to-device uniformity. The fabricated sensor element has an outer diameter of only 366 μm, which is small enough to be inserted into the rodent discs without disrupting the structure or altering the intradiscal pressures. In the calibration, the sensor element exhibits a linear response to the applied pressure over the range of 0 - 70 kPa, with a sensitivity of 0.0206 μm/kPa and a resolution of 0.17 kPa.

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Anatomic and Biochemical Correlates of the Dopamine Transporter Ligand 11C-PE2I in Normal and Parkinsonian Primates: Comparison with 6-[18F]Fluoro-L-Dopa

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200107000-00003 ◽

2001 ◽

Vol 21 (7) ◽

pp. 782-792 ◽

Cited By ~ 39

Author(s):

Thomas Poyot ◽

Françoise Condé ◽

Marie-Claude Grégoire ◽

Vincent Frouin ◽

Christine Coulon ◽

...

Keyword(s):

Gold Standard ◽

Dopaminergic Neurons ◽

Emission Tomography ◽

Attractive Alternative ◽

Input Rate ◽

Nigrostriatal Pathway ◽

Positron Emission ◽

Neuroprotective Strategies

Positron emission tomography (PET) coupled to 6-[18F]Fluoro-L-Dopa (18F-Dopa) remains the gold standard for assessing dysfunctionality concerning the dopaminergic nigrostriatal pathway in Parkinson's disease and related disorders. The use of ligands of the dopamine transporters (DAT) is an attractive alternative target; consequently, the current aim was to validate one of them, 11C-PE2I, using a multiinjection modeling approach allowing accurate quantitation of DAT densities in the striatum. Experiments were performed in three controls, three MPTP-treated (parkinsonian) baboons, and one reserpine-treated baboon. 11C-PE2I B′max values obtained with this approach were compared with 18F-Dopa input rate constant values (Ki), in vitro Bmax binding of 125I-PE2I, and the number of dopaminergic neurons in the substantia nigra estimated postmortem by stereology. In the caudate nucleus and putamen, control values for 11C-PE2I B'max were 673 and 658 pmol/mL, respectively, whereas it was strongly reduced in the MPTP-treated (B′max = 26 and 36 pmol/mL) and reserpine-treated animals (B′max = 338 and 483 pmol/mL). In vivo11C-PE2I B′max values correlated with 18F-Dopa Ki values and in vitro125I-PE2I Bmax values in the striatum and with the number of nigral dopaminergic neurons. Altogether, these data support the use of 11C-PE2I for monitoring striatal dopaminergic disorders and the effect of potential neuroprotective strategies.

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Abstract 124: Parthenogenetic Stem Cell-derived Cardiomyocytes Express Major Histocompatibility Complex-I only after Inflammatory Stimulation

Circulation Research ◽

10.1161/res.115.suppl_1.124 ◽

2014 ◽

Vol 115 (suppl_1) ◽

Author(s):

Satish Galla ◽

Michael Didie ◽

Vijayakumar Muppala ◽

Ralf Dressel ◽

Wolfram Hubertus Zimmermann

Keyword(s):

Major Histocompatibility Complex ◽

Heart Muscle ◽

Immunological Response ◽

Type I ◽

Major Histocompatibility ◽

Adrenergic Stimulation ◽

Mhc I ◽

Histocompatibility Complex

Background: Pluripotent parthenogenetic stem cells (PSCs) can be directed towards a cardiac fate and utilized in tissue engineered heart repair. In vivo applications of tissue engineered allografts are compromised by expression of mismatching major histocompatibility complex proteins (MHC; encoded in the murine H2 locus). Here we investigated whether PSC-derived cardiomyocytes (CM) express MHC-I. Methods: Mouse PSCs (A3-line from B6D2F1 strain with haploidentical H2K d -locus) expressing a CM-specific neomycin-resistance and GFP were differentiated and purified for CM by addition of G418 (85% purity by FACS for actinin). To simulate heart muscle biology in vitro, we made use of engineered heart muscle (EHM) constructed from PSC-derived CM (75%), growth-inhibited murine embryonic fibroblasts (MEF (25%); NMRI mice), and collagen type I. MHC class-I H2K d (MHC-I) expression was assessed on CM and Non myocytes before EHM assembly and from enzymatically digested EHMs (cultured for 10 days) by FACS. Interferon gamma (IFNγ) was added for 48 h to stimulate MHC-I expression. As a reference, we investigated MHC-I expression in CM from neonatal mice and adult mouse hearts by FACS and by immunofluorescence staining. Results: EHM showed a positive ionotropic response to beta-adrenergic stimulation which could be reduced by muscarinergic stimulation. A3-CM, in contrast to Non myocytes, showed negligible expression of MHC-I (1±0.5% vs. 60±10% positive cells; n=3). EHM culture did not change MHC-I expression in CM. IFNγ treatment resulted in a marked increase of MHC-I-expression in CM monolayer culture (40±6%; n=3) and in EHM (30±8%; n=3). For comparison, 30% (n=2) neonatal CM expressed MHC-I while MHC-I was not detectable in adult CM. Conclusion: PSC-derived CM show a similarly low expression of MHC-I as adult CM and respond with MHC-I upregulation to IFNγ stimulation. This suggests a mature immunological response in PSC-CM with important implications for in vivo applications, i.e., MHC-I matching will likely be a prerequisite for successful allografting of PSC-EHM.

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Mechanotransduction and Adrenergic Stimulation in Arrhythmogenic Cardiomyopathy: An Overview of in vitro and in vivo Models

Frontiers in Physiology ◽

10.3389/fphys.2020.568535 ◽

2020 ◽

Vol 11 ◽

Author(s):

Giorgia Beffagna ◽

Elena Sommariva ◽

Milena Bellin

Keyword(s):

Adrenergic Stimulation ◽

Arrhythmogenic Cardiomyopathy ◽

In Vivo Models

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A Critical Review of the Durability of Adhesion to Tooth Tissue: Methods and Results

Journal of Dental Research ◽

10.1177/154405910508400204 ◽

2005 ◽

Vol 84 (2) ◽

pp. 118-132 ◽

Cited By ~ 901

Author(s):

J. De Munck ◽

K. Van Landuyt ◽

M. Peumans ◽

A. Poitevin ◽

P. Lambrechts ◽

...

Keyword(s):

Gold Standard ◽

Test Method ◽

Chemical Degradation ◽

Morphological Evidence ◽

Aging Effects ◽

Application Procedure ◽

Etch And Rinse ◽

Clinical Benefits

The immediate bonding effectiveness of contemporary adhesives is quite favorable, regardless of the approach used. In the long term, the bonding effectiveness of some adhesives drops dramatically, whereas the bond strengths of other adhesives are more stable. This review examines the fundamental processes that cause the adhesion of biomaterials to enamel and dentin to degrade with time. Non-carious class V clinical trials remain the ultimate test method for the assessment of bonding effectiveness, but in addition to being high-cost, they are time- and labor-consuming, and they provide little information on the true cause of clinical failure. Therefore, several laboratory protocols were developed to predict bond durability. This paper critically appraises methodologies that focus on chemical degradation patterns of hydrolysis and elution of interface components, as well as mechanically oriented test set-ups, such as fatigue and fracture toughness measurements. A correlation of in vitro and in vivo data revealed that, currently, the most validated method to assess adhesion durability involves aging of micro-specimens of biomaterials bonded to either enamel or dentin. After about 3 months, all classes of adhesives exhibited mechanical and morphological evidence of degradation that resembles in vivo aging effects. A comparison of contemporary adhesives revealed that the three-step etch-and-rinse adhesives remain the ‘gold standard’ in terms of durability. Any kind of simplification in the clinical application procedure results in loss of bonding effectiveness. Only the two-step self-etch adhesives approach the gold standard and do have some additional clinical benefits.

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Enhancement by vasopressin of adrenergic responses in human mesenteric arteries

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1997.272.3.h1087 ◽

1997 ◽

Vol 272 (3) ◽

pp. H1087-H1093 ◽

Cited By ~ 7

Author(s):

P. Medina ◽

I. Noguera ◽

M. Aldasoro ◽

J. M. Vila ◽

B. Flor ◽

...

Keyword(s):

Electrical Stimulation ◽

Animal Experiments ◽

Mesenteric Arteries ◽

Organ Bath ◽

Adrenergic Stimulation ◽

Response Curves ◽

Receptor Stimulation ◽

Half Maximal Effective Concentration

Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited by electrical stimulation at 2, 4, and 8 Hz (by 100, 100, and 72%, respectively) and produced a leftward shift of the concentration-response curves to norepinephrine (half-maximal effective concentration decreased from 2.2 x 10(-6) to 5.0 x 10(-7) M; P < 0.05) without any alteration in maximal contractions. Vasopressin also potentiated KCl- and calcium-induced contractions. The V1-receptor antagonist 1-[beta-mercapto-beta,beta-cyclopentamethylenepropionic acid-2-O-methyl-tyrosine, 8-arginine]vasopressin (10(-6) M) prevented the potentiation evoked by vasopressin in all cases. The calcium antagonist nifedipine (10(-6) M) did not affect the potentiation of electrical stimulation and norepinephrine induced by vasopressin but abolished KCl-induced contractions. The results suggest that vasopressin, in addition to its direct vasoconstrictor effect, strongly potentiates the responses to adrenergic stimulation and KCl depolarization. Both the direct and indirect effects of vasopressin appear to be mediated by V1-receptor stimulation. The amplifying effect of vasopressin on constrictor responses may be relevant in those clinical situations characterized by increased plasma vasopressin levels.

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An Implantable Sensorized Lead for Continuous Monitoring of Cardiac Apex Rotation

Sensors ◽

10.3390/s18124195 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4195

Author(s):

Emanuela Marcelli ◽

Laura Cercenelli

Keyword(s):

Continuous Monitoring ◽

Dimensional Space ◽

Animal Experiments ◽

Three Dimensional ◽

Pressure Sensors ◽

Cardiac Monitoring ◽

Cardiac Apex ◽

Angular Velocities

Changes in the pattern or amplitude of cardiac rotation have been associated with important cardiovascular diseases, including Heart Failure (HF) which is one of the major health problems worldwide. Recent advances in echocardiographic techniques have allowed for non-invasive quantification of cardiac rotation; however, these examinations do not address the continuous monitoring of patient status. We have presented a newly developed implantable, transvenous lead with a tri-axis (3D) MEMS gyroscope incorporated near its tip to measure cardiac apex rotation in the three-dimensional space. We have named it CardioMon for its intended use for cardiac monitoring. If compared with currently proposed implantable systems for HF monitoring based on the use of pressure sensors that can have reliability issues, an implantable motion sensor like a gyroscope holds the premise for more reliable long term monitoring. The first prototypal assembly of the CardioMon lead has been tested to assess the reliability of the 3D gyroscope readings. In vitro results showed that the novel sensorized CardioMon lead was accurate and reliable in detecting angular velocities within the range of cardiac twisting velocities. Animal experiments will be planned to further evaluate the CardioMon lead in in vivo environments and to investigate possible endocardial implantation sites.

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