scholarly journals The Development of Equipment to Measure Mesh Erosion of Soft Tissue

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 941
Author(s):  
Amanda Schmidt ◽  
Gordon O’Brien ◽  
David Taylor
Keyword(s):  
Soft Tissue ◽  
Surgical Mesh ◽  
Testing Machine ◽  
Mesh Erosion ◽  
Tissue Type ◽  
Stroke Length ◽  
Characteristics Analysis ◽  
Erosion Mechanisms ◽  
Reciprocating Movement

Mesh erosion is a phenomenon whereby soft tissue becomes damaged as a result of contact with implants made from surgical mesh, a fabric-like material consisting of fibers of polypropylene or other polymers. This paper describes the design and construction of a testing machine to generate mesh erosion in vitro. A sample of mesh in the form of a 10 mm wide tape is pressed against soft tissue (porcine muscle) with a given force, and a given reciprocating movement is applied between the mesh and the tissue. To demonstrate the capabilities of the equipment, we measured erosion using the same mesh and tissue type, varying the applied force and the reciprocating stroke length, including zero strokes (i.e., static loading). For comparison, we also tested four other samples of polypropylene with different edge characteristics. Analysis of the results suggests the existence of three different erosion mechanisms: cutting, wear and creep. It is concluded that the equipment provides a useful and realistic simulation of mesh erosion, a phenomenon that is of great clinical significance and merits further study.

Tissue model and preliminary analysis of microdebriders used in functional endoscopic sinus surgery

2005 ◽  
Vol 132 (6) ◽  
pp. 834-839 ◽  
Author(s):  
Sandeep P. Dave ◽  
David A. Lehman ◽  
Roy R. Casiano
Keyword(s):  
Soft Tissue ◽  
Secondary Analysis ◽  
Functional Endoscopic Sinus Surgery ◽  
Sinus Surgery ◽  
Tissue Type ◽  
Tissue Model ◽  
Aspiration Efficiency ◽  
Basic Statistical Analysis ◽  
Larger Sample

OBJECTIVE: To develop a standardized in vitro tissue model for microdebrider comparison, and determine which microdebrider, tissue type, blade type, and suction strength is most efficient. STUDY DESIGN AND SETTING: A prospective randomized comparison of the Diego Powered Dissector and XPS 3000 Powered ENT System was conducted using a soft-tissue and a firm-tissue model. In addition to evaluating tissue aspiration with straight and angled blades, clogging rates and clearance times were measured. Both standard wall suction and liposuction were used. Basic statistical analysis and a one-way analysis of variance using confidence intervals were performed to compare outcomes. RESULTS: The aspiration of soft tissue was statistically superior to and demonstrated less clogging compared to the aspiration of firm tissue. For the “head-to-head” comparison, the XPS 3000 was statistically superior for aspirating soft tissue. When liposuction was excluded, the devices were essentially equivalent. Several notable trends that were not statistically significant were also observed. The aspiration efficiency of straight blades appeared to be superior compared to angled blades. The XPS 3000 and liposuction independently seemed to aspirate more tissue than the Diego Powered Dissector and regular suction, but at the expense of increased clogging. Finally, the Diego Powered Dissector showed a trend toward aspirating more firm tissue. CONCLUSION: Our tissue model represents a reliable and reproducible means of microdebrider comparison. A secondary analysis with a larger sample size is warranted to further validate the tissue model, to improve the power of the statistically significant results, and to better delineate the trends that were observed in the current study.

Fibrin-specificity of a Plasminogen Activator Affects the Efficiency of Fibrinolysis and Responsiveness to Ultrasound: Comparison of Nine Plasminogen Activators In Vitro

1999 ◽  
Vol 81 (04) ◽  
pp. 605-612 ◽  
Author(s):  
Dmitry V. Sakharov ◽  
Marrie Barrett-Bergshoeff ◽  
Rob T. Hekkenberg ◽  
Dingeman C. Rijken
Keyword(s):  
Thrombolytic Therapy ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Bolus Administration ◽  
High Frequency Ultrasound ◽  
Single Chain ◽  
Response Curves ◽  
Maximal Speed ◽  
Frequency Ultrasound

SummaryIn a number of cases, thrombolytic therapy fails to re-open occluded blood vessels, possibly due to the occurrence of thrombi resistant to lysis. We investigated in vitro how the lysis of hardly lysable model thrombi depends on the choice of the plasminogen activator (PA) and is accelerated by ultrasonic irradiation. Lysis of compacted crosslinked human plasma clots was measured after addition of nine different PAs to the surrounding plasma and the effect of 3 MHz ultrasound on the speed of lysis was assessed.Fibrin-specific PAs showed bell-shaped dose-response curves of varying width and height. PAs with improved fibrin-specificity (staphylokinase, the TNK variant of tissue-type PA [tPA], and the PA from the saliva of the Desmodus rotundus bat) induced rapid lysis in concentration ranges (80-, 260-, and 3,500-fold ranges, respectively) much wider than that for tPA (a 35-fold range). However, in terms of speed of lysis, these three PAs exceeded tPA only slightly. Reteplase and single-chain urokinase were comparable to tPA, whereas two-chain urokinase, anistreplase, and streptokinase were inferior to tPA. In the case of fibrin-specific PAs, ultrasonic treatment accelerated lysis about 1.5-fold. For streptokinase no acceleration was observed. The effect of ultrasound correlated with the presence of plasminogen in the outer plasma, suggesting that it was mediated by facilitating the transport of plasminogen to the surface of the clot.In conclusion, PAs with improved fibrin-specificity induce rapid lysis of plasminogen-poor compacted plasma clots in much wider concentration ranges than tPA. This offers a possibility of using single-or double-bolus administration regimens for such PAs. However, it is not likely that administration of these PAs will directly cause a dramatic increase in the rate of re-opening of the occluded arteries since they are only moderately superior to tPA in terms of maximal speed of lysis. Application of high-frequency ultrasound as an adjunct to thrombolytic therapy may increase the treatment efficiency, particularly in conjunction with fibrin-specific PAs.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

A Monoclonal Antibody-Based Enzyme Immunoassay for Fibrin Degradation Products in Plasma

1988 ◽  
Vol 59 (02) ◽  
pp. 310-315 ◽  
Author(s):  
P W Koppert ◽  
E Hoegee-de Nobel ◽  
W Nieuwenhuizen
Keyword(s):  
Enzyme Immunoassay ◽  
Degradation Products ◽  
Blood Clot ◽  
Tissue Type ◽  
Fibrin Degradation Products ◽  
Type Plasminogen Activator ◽  
Strong Positive Reaction ◽  
Sandwich Type ◽  
Capture Antibody

SummaryWe have developed a sandwich-type enzyme immunoassay (EIA) for the quantitation of fibrin degradation products (FbDP) in plasma with a time-to-result of only 45 minutes.* The assay is based on the combination of the specificities of two monoclonal antibodies (FDP-14 and DD-13), developed in our institute. FDP-14, the capture antibody, binds both fibrinogen degradation products (FbgDP) and FbDP, but does not react with the parent fibrin(ogen) molecules. It has its epitope in the E-domain of the fibrinogen molecule on the Bβ-chain between amino acids 54-118. Antibody DD-13 was raised using D-dimer as antigen and is used as a tagging antibody, conjugated with horse-radish peroxidase. A strong positive reaction is obtained with a whole blood clot lysate (lysis induced by tissue-type plasminogen activator) which is used as a standard. The EIA does virtually not detect FbgDP i. e. purified fragments X, Y, or FbgDP generated in vitro in plasma by streptokinase treatment. This indicates that the assay is specific for fibrin degradation products.We have successfully applied this assay to the plasma of patients with a variety of diseased states. In combination with the assay previously developed by us for FbgDP and for the total amount of FbgDP + FbDP (TDP) in plasma, we are now able to study the composition of TDP in patients plasma in terms of FbgDP and FbDP.

Activated Protein C Increases Fibrin Clot Lysis by Neutralization of Plasminogen Activator Inhibitor No Evidence for a Cofactor Role of Protein S

1988 ◽  
Vol 60 (02) ◽  
pp. 328-333 ◽  
Author(s):  
N J de Fouw ◽  
Y F de Jong ◽  
F Haverkate ◽  
R M Bertina
Keyword(s):  
Plasminogen Activator ◽  
Protein C ◽  
Blood Platelets ◽  
Plasminogen Activator Inhibitor ◽  
Protein S ◽  
Tissue Type ◽  
Clot Lysis ◽  
Activator Inhibitor ◽  
Pai 1

summaryThe effect of purified human activated protein G (APC) on fibrinolysis was studied using a clot iysis system consisting of purified glu-plasminogen, tissue-type plasminogen activator, plasminogen activator inhibitor (released from endothelial cells or blood platelets), fibrinogen, 125T-fibrinogen and thrombin. All proteins were of human origin.In this system APC could increase fibrinolysis in a dose dependent way, without affecting fibrin formation or fibrin crosslinking. However, this profibrinolytic effect of APC could only be observed when plasminogen activator inhibitor (PAI-l) was present. The effect of APC was completely quenched by pretreatment of APC with anti-protein C IgG or di-isopropylfluorophosphate. Addition of the cofactors of APC:protein S, Ca2+-ions and phospholipid-alone or in combination did not enhance the profibrinolytic effect of APC. These observations indicate that human APC can accelerate in vitro clot lysis by the inactivation of PAI-1 activity. However, the neutralization of PAI-1 by APC is independent of the presence or absence of protein S, phospholipid and Ca2+-ions.

Pharmacokinetics and Haemostatic Status During Consecutive Infusions of Recom binant Tissue-Type Plasminogen Activator in Patients with Acute Myocardial Infarction

1989 ◽  
Vol 61 (03) ◽  
pp. 497-501 ◽  
Author(s):  
E Seifried ◽  
P Tanswell ◽  
D Ellbrück ◽  
W Haerer ◽  
A Schmidt
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Plasminogen Activator ◽  
Peak Plasma ◽  
Peak Plasma Concentration ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Precise Control ◽  
Type Plasminogen Activator

SummaryPharmacokinetics and systemic effects of recombinant tissue type plasminogen activator (rt-PA) were determined during coronary thrombolysis in 12 acute myocardial infarction patients using a consecutive intravenous infusion regimen. Ten mg rt-PA were infused in 2 minutes resulting in a peak plasma concentration (mean ±SD) of 3310±950 ng/ml, followed by 50 mg in 1 h and 30 mg in 1.5 h yielding steady state plasma levels of. 2210±470 nglml and 930±200 ng/ml, respectively. All patients received intravenous heparin. Total clearance of rt-PA was 380±74 ml/min, t,½α was 3.6±0.9 min and t,½β was 16±5.4 min.After 90 min, in plasma samples containing anti-rt-PA-IgG to inhibit in vitro effects, fibrinogen was decreased to 54%, plasminogen to 52%, α2-antiplasmin to 25%, α2-macroglobulin to 90% and antithrombin III to 85% of initial values. Coagulation times were prolonged and fibrin D-dimer concentrations increased from 0.40 to 2.7 μg/ml. It is concluded that pharmacokinetics of rt-PA show low interpatient variability and that its short mean residence time in plasma allows precise control of therapy. Apart from its moderate effect on the haemostatic system, rt-PA appears to lyse a fibrin pool in addition to the coronary thrombus.

Comparison of Specific Antibody, D-Phe-Pro-Arg-CH2Cl and Aprotinin for Prevention of In Vitro Effects of Recombinant Tissue-Type Plasminogen Activator on Haemostasis Parameters

1987 ◽  
Vol 58 (03) ◽  
pp. 921-926 ◽  
Author(s):  
E Seifried ◽  
P Tanswell
Keyword(s):  
Specific Antibody ◽  
Plasma Concentrations ◽  
Fibrinolytic Therapy ◽  
Tissue Type ◽  
Control Value ◽  
Type Plasminogen Activator ◽  
In Vitro Effects ◽  
Fibrinolytic Parameters

SummaryIn vitro, concentration-dependent effects of rt-PA on a range of coagulation and fibrinolytic assays in thawed plasma samples were investigated. In absence of a fibrinolytic inhibitor, 2 μg rt-PA/ml blood (3.4 μg/ml plasma) caused prolongation of clotting time assays and decreases of plasminogen (to 44% of the control value), fibrinogen (to 27%), α2-antiplasmin (to 5%), FV (to 67%), FVIII (to 41%) and FXIII (to 16%).Of three inhibitors tested, a specific polyclonal anti-rt-PA antibody prevented interferences in all fibrinolytic and most clotting assays. D-Phe-Pro-Arg-CH2Cl (PPACK) enabled correct assays of fibrinogen and fibrinolytic parameters but interfered with coagulometric assays dependent on endogenous thrombin generation. Aprotinin was suitable only for a restricted range of both assay types.Most in vitro effects were observed only with rt-PA plasma concentrations in excess of therapeutic values. Nevertheless it is concluded that for clinical application, collection of blood samples on either specific antibody or PPACK is essential for a correct assessment of in vivo effects of rt-PA on the haemostatic system in patients undergoing fibrinolytic therapy.

In Vitro Stability of a Tissue-Type Plasminogen Activator Mutant, BM 06.022, in Human Plasma

1994 ◽  
Vol 72 (06) ◽  
pp. 906-911 ◽  
Author(s):  
D C Rijken ◽  
E Groeneveld ◽  
M M Barrett-Bergshoeff
Keyword(s):  
Plasminogen Activator ◽  
Half Life ◽  
Polyacrylamide Gel Electrophoresis ◽  
Tissue Type ◽  
Single Chain ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Sds Page ◽  
Chain Form

SummaryBM 06.022 is a non-glycosylated mutant of human tissue-type plasminogen activator (t-PA) comprising only the kringle-2 and proteinase domains. The in vivo half-life of BM 06.022 antigen is 4- to 5-fold longer than that of t-PA antigen. The in vitro half-life of the activity of BM 06.022 at therapeutic concentrations in plasma is shorter than that of t-PA. In this study the inactivation of BM 06.022 in plasma was further investigated.Varying concentrations of BM 06.022 were incubated in plasma for 0-150 min. Activity assays on serial samples showed a dose-dependent decline of BM 06.022 activity with a half-life from 72 min at 0.3 μg/ml to 38 min at 10 μg/ml. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by fibrin autography showed the generation of several BM 06.022-complexes. These complexes could be completely precipitated with antibodies against Cl-inactivator, α2-antiplasmin and α1-antitrypsin.During the incubation of BM 06.022 in plasma, plasmin was generated dose-dependently as revealed by varying degrees of a2-anti-plasmin consumption and fibrinogen degradation. SDS-PAGE and immunoblotting showed that single-chain BM 06.022 was rapidly (i. e. within 45 min) converted into its two-chain form at concentrations of 5 μg/ml BM 06.022 and higher.In conclusion, BM 06.022 at therapeutic concentrations in plasma was inactivated by Cl-inactivator, a2-antiplasmin and a j-antitrypsin. The half-life of the activity decreased at increasing BM 06.022 concentrations, probably as a result of the generation of two-chain BM 06.022 which may be inactivated faster than the single-chain form.

Perturbation of Platelet Adhesion to Endothelial Cells by Plasminogen Activation In Vitro

1997 ◽  
Vol 78 (02) ◽  
pp. 934-938 ◽  
Author(s):  
Hsiun-ing Chen ◽  
Yueh-I Wu ◽  
Yu-Lun Hsieh ◽  
Guey-Yueh Shi ◽  
Meei-Jyh Jiang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Platelet Adhesion ◽  
Treatment Time ◽  
Shape Change ◽  
Umbilical Vein ◽  
Tissue Type ◽  
Apical Surface ◽  
Plasminogen Activation

SummaryTo investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as e-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.

The Effect of Pentosan Polysulphate (SP54) on the Fibrinolytic Enzyme System - A Human Volunteer and Experimental Animal Study

1985 ◽  
Vol 54 (04) ◽  
pp. 833-837 ◽  
Author(s):  
N A Marsh ◽  
P M Peyser ◽  
L J Creighton ◽  
M Mahmoud ◽  
P J Gaffney
Keyword(s):  
Plasminogen Activator ◽  
Surface Effect ◽  
Ex Vivo ◽  
Vena Cava ◽  
Tissue Type ◽  
Similar Response ◽  
Small Contribution ◽  
Thrombosis Model ◽  
Pentosan Polysulphate

SummaryPentosan polysulphate causes an increase in plasminogen activator activity in plasma both after oral ingestion and after subcutaneous injection. The effect is greatest after 3 h and has disappeared by 6 h. Repeat doses by mouth over 5 days elicit a similar response. The recorded increase in activity is due largely to the release of tissue-type plasminogen activator (tPA) from the endothelium according to the antigen assay although there could be a small contribution from Factor XH-related “intrinsic” fibrinolysis induced in vitro. SP54 enhances activity ex vivo by a non-specific surface effect, and this phenomenon may contribute the increased levels of activity seen in vitro. Administration of SP54 to animals elicits a similar increase in activator activity, the intramuscular route being slightly more effective. Results with an inferior vena cava thrombosis model in the rat suggest that pentosan polysulphate may induce a thrombolytic effect.

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