scholarly journals Performance of microvascular anastomosis with a new robotic visualization system: proof of concept

2021 ◽  
Author(s):  
F. Boehm ◽  
P. J. Schuler ◽  
R. Riepl ◽  
L. Schild ◽  
T. K. Hoffmann ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Body Position ◽  
Head Movements ◽  
Camera System ◽  
Visualization System ◽  
Head Mounted Display ◽  
General Evaluation ◽  
Surgical Field ◽  
Technical Instructions

AbstractMicrovascular procedures require visual magnification of the surgical field, e.g. by a microscope. This can be accompanied by an unergonomic posture with musculoskeletal pain or long-term degenerative changes as the eye is bound to the ocular throughout the whole procedure. The presented study describes the advantages and drawbacks of a 3D exoscope camera system. The RoboticScope®-system (BHS Technologies®, Innsbruck, Austria) features a high-resolution 3D-camera that is placed over the surgical field and a head-mounted-display (HMD) that the camera pictures are transferred to. A motion sensor in the HMD allows for hands-free change of the exoscope position via head movements. For general evaluation of the system functions coronary artery anastomoses of ex-vivo pig hearts were performed. Second, the system was evaluated for anastomosis of a radial-forearm-free-flap in a clinical setting/in vivo. The system positioning was possible entirely hands-free using head movements. Camera control was intuitive; visualization of the operation site was adequate and independent from head or body position. Besides technical instructions of the providing company, there was no special surgical training of the surgeons or involved staff upfront performing the procedures necessary. An ergonomic assessment questionnaire showed a favorable ergonomic position in comparison to surgery with a microscope. The outcome of the operated patient was good. There were no intra- or postoperative complications. The exoscope facilitates a change of head and body position without losing focus of the operation site and an ergonomic working position. Repeated applications have to clarify if the system benefits in clinical routine.

scholarly journals In vivo ratiometric optical mapping enables high-resolution cardiac electrophysiology in pig models

2019 ◽  
Vol 115 (11) ◽  
pp. 1659-1671 ◽  
Author(s):  
Peter Lee ◽  
Jorge G Quintanilla ◽  
José M Alfonso-Almazán ◽  
Carlos Galán-Arriola ◽  
Ping Yan ◽  
...  
Keyword(s):  
High Resolution ◽  
Cardiac Electrophysiology ◽  
High Speed ◽  
Near Infrared ◽  
Optical Mapping ◽  
Ex Vivo ◽  
Average Rate ◽  
Camera System ◽  
Epicardial Surface

Abstract Aims Cardiac optical mapping is the gold standard for measuring complex electrophysiology in ex vivo heart preparations. However, new methods for optical mapping in vivo have been elusive. We aimed at developing and validating an experimental method for performing in vivo cardiac optical mapping in pig models. Methods and results First, we characterized ex vivo the excitation-ratiometric properties during pacing and ventricular fibrillation (VF) of two near-infrared voltage-sensitive dyes (di-4-ANBDQBS/di-4-ANEQ(F)PTEA) optimized for imaging blood-perfused tissue (n = 7). Then, optical-fibre recordings in Langendorff-perfused hearts demonstrated that ratiometry permits the recording of optical action potentials (APs) with minimal motion artefacts during contraction (n = 7). Ratiometric optical mapping ex vivo also showed that optical AP duration (APD) and conduction velocity (CV) measurements can be accurately obtained to test drug effects. Secondly, we developed a percutaneous dye-loading protocol in vivo to perform high-resolution ratiometric optical mapping of VF dynamics (motion minimal) using a high-speed camera system positioned above the epicardial surface of the exposed heart (n = 11). During pacing (motion substantial) we recorded ratiometric optical signals and activation via a 2D fibre array in contact with the epicardial surface (n = 7). Optical APs in vivo under general anaesthesia showed significantly faster CV [120 (63–138) cm/s vs. 51 (41–64) cm/s; P = 0.032] and a statistical trend to longer APD90 [242 (217–254) ms vs. 192 (182–233) ms; P = 0.095] compared with ex vivo measurements in the contracting heart. The average rate of signal-to-noise ratio (SNR) decay of di-4-ANEQ(F)PTEA in vivo was 0.0671 ± 0.0090 min−1. However, reloading with di-4-ANEQ(F)PTEA fully recovered the initial SNR. Finally, toxicity studies (n = 12) showed that coronary dye injection did not generate systemic nor cardiac damage, although di-4-ANBDQBS injection induced transient hypotension, which was not observed with di-4-ANEQ(F)PTEA. Conclusions In vivo optical mapping using voltage ratiometry of near-infrared dyes enables high-resolution cardiac electrophysiology in translational pig models.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

Antithrombotic Effects and Bleeding Time Prolongation with Synthetic Platelet GPIIb/llla Inhibitors in Animal Models of Platelet-Mediated Thrombosis

1994 ◽  
Vol 71 (01) ◽  
pp. 095-102 ◽  
Author(s):  
Désiré Collen ◽  
Hua Rong Lu ◽  
Jean-Marie Stassen ◽  
Ingrid Vreys ◽  
Tsunehiro Yasuda ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Bleeding Time ◽  
Bolus Injection ◽  
Cell Injury ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Femoral Vein ◽  
Thrombotic Occlusion ◽  
Antithrombotic Effects

SummaryCyclic Arg-Gly-Asp (RGD) containing synthetic peptides such as L-cysteine, N-(mercaptoacetyl)-D-tyrosyl-L-arginylglycyl-L-a-aspartyl-cyclic (1→5)-sulfide, 5-oxide (G4120) and acetyl-L-cysteinyl-L-asparaginyl-L-prolyl-L-arginyl-glycyl-L-α-aspartyl-[0-methyltyrosyl]-L-arginyl-L-cysteinamide, cyclic 1→9-sulfide (TP9201) bind with high affinity to the platelet GPIIb/IIIa receptor.The relationship between antithrombotic effect, ex vivo platelet aggregation and bleeding time prolongation with both agents was studied in hamsters with a standardized femoral vein endothelial cell injury predisposing to platelet-rich mural thrombosis, and in dogs with a carotid arterial eversion graft inserted in the femoral artery. Intravenous administration of G4120 in hamsters inhibited in vivo thrombus formation with a 50% inhibitory bolus dose (ID50) of approximately 20 μg/kg, ex vivo ADP-induccd platelet aggregation with ID50 of 10 μg/kg, and bolus injection of 1 mg/kg prolonged the bleeding time from 38 ± 9 to 1,100 ± 330 s. Administration of TP9201 in hamsters inhibited in vivo thrombus formation with ID50 of 30 μg/kg, ex vivo platelet aggregation with an ID50 of 50 μg/kg and bolus injection of 1 mg/kg did not prolong the template bleeding time. In the dog eversion graft model, infusion of 100 μg/kg of G4120 over 60 min did not fully inhibit platelet-mediated thrombotic occlusion but was associated with inhibition of ADP-induccd ex vivo platelet aggregation and with prolongation of the template bleeding time from 1.3 ± 0.4 to 12 ± 2 min. Infusion of 300 μg/kg of TP9201 over 60 min completely prevented thrombotic occlusion, inhibited ex vivo platelet aggregation, but was not associated with prolongation of the template bleeding time.TP9201, unlike G4120, inhibits in vivo platelet-mediated thrombus formation without associated prolongation of the template bleeding time.

Significance of Platelet β-Adrenoceptors for Platelet Responses In Vivo and In Vitro

1992 ◽  
Vol 68 (06) ◽  
pp. 687-693 ◽  
Author(s):  
P T Larsson ◽  
N H Wallén ◽  
A Martinsson ◽  
N Egberg ◽  
P Hjemdahl
Keyword(s):  
Ex Vivo ◽  
High Dose ◽  
Platelet Aggregability ◽  
Adrenoceptor Agonist ◽  
Dose Infusion ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThe significance of platelet β-adrenoceptors for platelet responses to adrenergic stimuli in vivo and in vitro was studied in healthy volunteers. Low dose infusion of the β-adrenoceptor agonist isoprenaline decreased platelet aggregability in vivo as measured by ex vivo filtragometry. Infusion of adrenaline, a mixed α- and β-adrenoceptor agonist, increased platelet aggregability in vivo markedly, as measured by ex vivo filtragometry and plasma β-thromboglobulin levels. Adrenaline levels were 3–4 nM in venous plasma during infusion. Both adrenaline and high dose isoprenaline elevated plasma von Willebrand factor antigen levels β-Blockade by propranolol did not alter our measures of platelet aggregability at rest or during adrenaline infusions, but inhibited adrenaline-induced increases in vWf:ag. In a model using filtragometry to assess platelet aggregability in whole blood in vitro, propranolol enhanced the proaggregatory actions of 5 nM, but not of 10 nM adrenaline. The present data suggest that β-adrenoceptor stimulation can inhibit platelet function in vivo but that effects of adrenaline at high physiological concentrations are dominated by an α-adrenoceptor mediated proaggregatory action.

In Vivo Effect of Suloctidil as an Antiplatelet Agent

1979 ◽  
Vol 41 (03) ◽  
pp. 465-474 ◽  
Author(s):  
Marcia R Stelzer ◽  
Thomas S Burns ◽  
Robert N Saunders
Keyword(s):  
Ex Vivo ◽  
Antiplatelet Agent ◽  
Ratio Method ◽  
Platelet Aggregate ◽  
Permanent Effect ◽  
Platelet Aggregates ◽  
5 Ht Uptake ◽  
High Doses

SummaryThe relationship between the effects of suloctidil in vivo as an antiplatelet agent and in vitro as a modifier of platelet serotonin (5-HT) parameters was investigated. Suloctidil was found to be effective in reducing platelet aggregates formation in the retired breeder rat as determined using the platelet aggregate ratio method (PAR) with an ED50 of 16.1 mg/kg 24 hours post administration. In contrast to the hypothesis that 5-HT depletion is involved in the anti-aggregatory mechanism of suloctidil, no correlation was found between platelet 5- HT content and this antiplatelet activity. Reduction of platelet 5-HT content required multiple injections of high doses (100 mg/kg/day) of suloctidil. Suloctidil administration for 8 days at 100 mg/kg/day, which lowered platelet 5-HT content by 50%, resulted in no permanent effect on ex vivo platelet 5-HT uptake or thrombin-induced release, nor alteration in the plasma 5-HT level. However, these platelets exhibited a short-lived, significant increase in percent leakage of 5-HT after 30 minutes of incubation. Therefore, suloctidil treatment at high doses may with time result in platelet 5-HT depletion, however this effect is probably not related to the primary anti-aggregatory activity of the drug.

Studies on the Haemostatic Defect in a Complicated Syndrome

1995 ◽  
Vol 74 (05) ◽  
pp. 1244-1251 ◽  
Author(s):  
H Stormorken ◽  
H Holmsen ◽  
R Sund ◽  
K S Sakariassen ◽  
T Hovig ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Bleeding Tendency ◽  
Clot Retraction ◽  
Abnormal Finding ◽  
Shear Rates ◽  
Perfusion Chamber ◽  
Coagulant Activity ◽  
5 Ht Uptake ◽  
And Storage

SummaryThe Stormorken syndrome is a multifacetted syndrome including a bleeding tendency. No deviations were found in the coagulation- or fibrinolytic systems. Platelet number was low normal, and size abnormal, whereas EM findings were unremarkable. Survival time was half normal. Clot retraction was initially rapid, but clearly decreased, whereas prothrombin consumption was also initially rapid, but complete. Membrane GP’s were normal, so was AA metabolism, PI-cycle, granule storage and secretion, and c-AMP function, whereas 5-HT uptake and storage was decreased. Optical platelet aggregation was low normal with all physiological agonists. The only clearly abnormal finding was that coagulant activity was present on non stimulated platelets at the same level as kaolin-stimulated normal platelets. This indicated a platelet abnormality which should lead to a thrombogenic, not to a haemorrhagic trait. This paradox may have its origin in rheology, because when challenged with in vivo shear rates in an ex vivo perfusion chamber, platelet cohesion was abnormally low. Further studies to better delineate the membrane abnormality are underway.

A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

1977 ◽  
Vol 37 (01) ◽  
pp. 154-161 ◽  
Author(s):  
B. A Janik ◽  
S. E Papaioannou
Keyword(s):  
Side Effects ◽  
Effective Dose ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Plasminogen Activators ◽  
Assay System ◽  
Coagulation Parameters ◽  
Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

Ex Vivo Inhibition of Platelet Aggregation in Patients with Severe Limb Arteriopathy Treated with BAY U3405, a Specific IX A2 Receptor Antagonist

1994 ◽  
Vol 72 (05) ◽  
pp. 659-662 ◽  
Author(s):  
S Bellucci ◽  
W Kedra ◽  
H Groussin ◽  
N Jaillet ◽  
P Molho-Sabatier ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Ex Vivo ◽  
Randomized Study ◽  
In Vivo Studies ◽  
Walking Distance ◽  
Peripheral Blood Flow ◽  
Walking Ability ◽  
Double Blind ◽  
Platelet Factor

SummaryA double-blind, placebo-controlled randomized study with BAY U3405, a specific thromboxane A2 (TX A2) receptor blocker, was performed in patients suffering from severe stade II limb arteriopathy. BAY U3405 or placebo was administered in 16 patients at 20 mg four times a day (from day 1 to day 3). Hemostatic studies were done before therapy, and on day 2 and day 3 under therapy. On day 3, BAY U3405 was shown to induce a highly statistically significant decrease of the velocity and the intensity of the aggregations mediated by arachidonic acid (56 ± 37% for the velocity, 58 ± 26% for the intensity) or by U46619 endoperoxide analogue (36 ± 35% for the velocity, 37 ± 27% for the intensity). Similar results were already observed on day 2. By contrast, such a decrease was not noticed with ADP mediated platelet aggregation. Furthermore, plasma levels of betathrombo-globulin and platelet factor 4 remained unchanged. Peripheral hemodynamic parameters were also studied. The peripheral blood flow was measured using a Doppler ultrasound; the pain free walking distance and the total walking ability distance were determined under standardized conditions on a treadmill. These last two parameters show a trend to improvement which nevertheless was not statistically significant. All together these results encourage further in vivo studies using BAY U3405 or related compounds on a long-term administration.

Inhibition of Fibrinolytic Activity In-Vivo by Dexamethasone Is Counterbalanced by an Inhibition of Platelet Aggregation

1992 ◽  
Vol 68 (01) ◽  
pp. 069-073 ◽  
Author(s):  
J J J van Giezen ◽  
J W C M Jansen
Keyword(s):  
Platelet Aggregation ◽  
Fibrinolytic Activity ◽  
Ex Vivo ◽  
Dose Range ◽  
Coagulation System ◽  
Loop Model ◽  
Prothrombotic State ◽  
Inhibition Of Platelet Aggregation ◽  
Pai 1

SummaryDexamethasone decreases the fibrinolytic activity in cultured medium of several cell types by an induction of PAI-1 synthesis. As a result of this enhanced PAI-1 synthesis a prothrombotic state is expected in patients treated with dexamethasone. However, such a prothrombotic state is not reported as a major adverse effect. We have studied the effects of dexamethasone (dose range: 0.1–3.0 mg/kg) on the fibrinolytic system of rats after a 5 day pretreatment period. It appeared that dexamethasone dose dependently decreased the fibrinolytic activity (a dose of 1 mg/kg showed a reduction of about 40%). This reduced fibrinolytic activity could be functionally translated into an increased thrombus size as measured with a venous thrombosis model: thrombus size was increased by 50% with 1 mg/kg dexamethasone. No effects could be measured on the coagulation system, but it appeared that ex-vivo measured platelet aggregation was dose dependently inhibited by dexamethasone treatment. This effect resulted in-vivo in prolonged obstruction times as measured with a modified aorta-loop model. These results indicate that the expected prothrombotic state due to a diminished fibrinolytic activity caused by dexamethasone is counterbalanced by an inhibition of platelet aggregation.

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