An in vitro method for comparing biocompatibility of materials for extracorporeal circulation

Perfusion ◽  
2002 ◽  
Vol 17 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Giles J Peek ◽  
Richard Scott ◽  
Hilliary M Killer ◽  
Richard K Firmin
Keyword(s):  
International Normalized Ratio ◽  
The Other ◽  
Clotting Time ◽  
Roller Pump ◽  
In Vitro Method ◽  
Cell Counts ◽  
Activated Clotting Time ◽  
Free Haemoglobin ◽  
Group 2

We measured the response of fresh heparinized human blood to recirculation through circuits made of LVA (Portex Industries, Hythe, Kent, UK), SRT (Rehau UK, Langley, Slough, UK) and Tygon® S-65-HL (Norton Performance Plastics, Corby, Northants, UK), as control. Circuit construction: 1/2 in. tubing, heat exchanger (Dideco D-720P), Stockert roller pump, just underoccluded, Cincinnati Sub Zero heater, circuit volume of 500 ml. Flow 3.45 l/min, 37°C. Samples: at 10 min, 1, 2, 4 and 6 h. n= 5 in each group; 2/5 SRT experiments were stopped at 45 and 60 min due to overpressurization. Results: Baseline activated clotting time (ACT) of 300 s, increasing in all groups as fibrinogen fell to zero with SRT and LVA. Minimum fibrinogen was 1 g/l for Tygon. Absolute thrombocytopenia occurred (SRT and LVA 60 min and Tygon 240 min). International normalized ratio (INR) in both the SRT and LVA circuits increased, but mean increase for Tygon (0.56) was smaller than the other two materials. Plasma free haemoglobin increased in all three materials; the increase was greater in the LVA circuits compared to the control. C5b9 levels increased equally in all groups. Lactoferrin levels rose equally in all groups to a maximum at 150 min. The neutrophil counts fell, mirroring the lactoferrin. The total white cell counts also fell in all groups; in the LVA circuits, the fall was significantly lower than in the control. Rapid disappearance of platelets and fibrinogen from the blood in the SRT and LVA circuits excludes them both from extracorporeal use. Paradoxically, SRT caused the least complement activation of the three materials. This method can be used to compare biocompatibility.

scholarly journals 28 SIMPLIFIED ACTIVATION METHOD TO IMPROVE THE IN VITRO DEVELOPMENT OF HANDMADE CLONED (HMC) PORCINE EMBRYOS

2009 ◽  
Vol 21 (1) ◽  
pp. 114
Author(s):  
Y. Du ◽  
Z. Yang ◽  
B. Lv ◽  
L. Lin ◽  
P. M. Kragh ◽  
...  
Keyword(s):  
Cell Number ◽  
Activation Method ◽  
The Other ◽  
Electrical Activation ◽  
In Vitro Development ◽  
Reconstructed Embryos ◽  
Fetal Fibroblasts ◽  
Group 2 ◽  
Vitro Development

Delayed activation is commonly used in pig somatic cell nuclear transfer (SCNT) where electrical activation is followed by chemical activation. However, chemical incubation of several hours (up to 4 or 6) is logistically not very convenient even though handmade cloning (HMC) could improve the overall efficiency of pig cloning (Du et al. 2007 Theriogenology 68, 1104–1110). It was reported that a brief exposure of cycloheximide (CX) before electrical activation could significantly increase developmental rate and total blastocyst cell number when simultaneous activation was performed in micromanipulator-based pig cloning (Naruse et al. 2007 Theriogenology 68, 709–716). The purpose of our present work is to investigate whether such activation method is also applicable for pig HMC. Data were analyzed by t-test using SPSS (11.0, SPSS Inc., Chicago, IL, USA). After 42 h in vitro maturation, cumulus cells were removed. In vitro-cultured porcine fetal fibroblasts were used as donor cells. Cytoplast-fibroblast pairing, electrical fusion and activation of fused cytoplast-fibroblast pairs were performed as described previously (Kragh et al. 2005 Theriogenology 64, 1536–1545; Du et al. 2005 Cloning Stem Cells 7, 199–205). Three groups were compared due to different activation protocol. In Group 1 (control), reconstructed embryos were cultured in porcine zygote medium 3 (PZM3) supplemented with 4 mg mL–1 BSA, 5 μg mL–1 cytochalasin B (CB), and 10 μg mL–1 CX for 4 h. In Group 2 (CX priming), fused pairs and the other halves of cytoplasts were incubated in HEPES-buffered TCM-199 medium supplemented with 10% calf serum, 10 μg mL–1 CX for 10 min just before the second fusion or electrical activation. In Group 3 (CB + CX priming), treatment similar to Group 2 was performed except that additional 5 μg mL–1 CB was added for the 10-min incubation. Reconstructed embryos were in vitro cultured in the well of the well (WOW) system for 6 days. Blastocyst rates and total cell numbers of Day 6 blastocysts were evaluated. As illustrated in Table 1, embryos pretreated with both CB and CX gave the best results, with better blastocyst formation (53.8 ± 4.8%; mean ± SEM) and higher cell number (77.2 ± 5.4) compared to the other 2 groups. Our data suggested that CX and CB priming could be used as a solution to the long chemical incubation in porcine SCNT by HMC, making the embryos more receptive to electrical activation. Table 1.In vitro development of HMC reconstructed embryos with different activation protocols

Factors associated with errors in the heparin dose response test: recommendations to improve individualized heparin management in cardiopulmonary bypass

Perfusion ◽  
2020 ◽  
pp. 026765912095297
Author(s):  
Min-Ho Lee ◽  
William Riley
Keyword(s):  
Cardiopulmonary Bypass ◽  
Dose Response ◽  
Clotting Time ◽  
Critical Aspect ◽  
Heparin Dose ◽  
Factors Associated ◽  
Heparin Concentration ◽  
Activated Clotting Time

Background: A critical aspect of cardiopulmonary bypass (CPB) is to achieve full anticoagulation to prevent thrombosis and consumptive coagulation without using excessive amount of heparin. This can be achieved with heparin dose response (HDR) test in vitro to calculate an individualized heparin bolus to reach a target activated clotting time (ACT) and heparin concentration. However, we often observe that the measured ACT (mACT) with the calculated heparin bolus gives significant errors, both positive (mACT is higher than expected) and negative (mACT is lower), from expected ACT (eACT). Methods: We performed a retrospective study of 250 patients who underwent cardiac surgery to attain an error distribution of the mACT from eACT with calculated heparin bolus. In addition, it is aimed to identify possible patterns of baseline ACT (bACT), calculated heparin concentration (CHC) and HDR slope that are associated with the significant positive and negative errors. Results: We found that individualized heparin bolus by HDR test is consistently underestimated while it gave a significant number of positive and negative errors. Further analysis indicates that significant negative errors correlate with high bACT and slope and low CHC while significant positive errors with low bACT and slope and high CHC. Conclusion: The mACT can be substantially different from eACT. The accuracy of the HDR test appears to be dependent upon bACT, slope, and CHC. Based on our analysis, we provide several recommendations and a flow chart to improve the quality of individualized heparin management on CPB.

A common pathway for sugar transport in hamster intestine

1961 ◽  
Vol 200 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Charles R. Jorgensen ◽  
Bernard R. Landau ◽  
T. Hastings Wilson
Keyword(s):  
Small Intestine ◽  
Transport Mechanism ◽  
Sugar Transport ◽  
The Other ◽  
Common Pathway ◽  
In Vitro Method ◽  
Single Segment ◽  
Other Hand

The competition between different sugars for the transport mechanism of hamster small intestine was tested with an in vitro method which allowed the use of a single segment of intestine for both control and experimental periods. The transport of the test sugar d-galactose was inhibited by other sugars known to be actively absorbed by the intestine; namely, d-glucose, α-methyl-d-glucoside, i-deoxy-d-glucose, 6-deoxy-d-glucose and 3-o-methyl-d-glucose. On the other hand d-mannose and d-xylose, two sugars not actively transported, did not inhibit d-galactose absorption. In addition, sugars known to be actively absorbed produced an inhibition of transport of d-glucose and 6-deoxy-d-glucose when these were selected as test sugars. The results of these experiments are consistent with the view that all transported sugars compete for a common pathway in hamster intestine. Various hypotheses of sugar transport are discussed in light of the present data.

Reliability of the Heparin Management Test for Monitoring High Levels of Unfractionated Heparin

2000 ◽  
Vol 92 (6) ◽  
pp. 1594-1602 ◽  
Author(s):  
Fritz Mertzlufft ◽  
Andreas Koster ◽  
Roland Hansen ◽  
Anne Risch ◽  
Herrmann Kuppe ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Storage Time ◽  
Coagulation Factors ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Group I ◽  
Group Ii ◽  
And Storage

Background The authors assessed the heparin management test in vitro in volunteers and in vivo during cardiopulmonary bypass. Methods In vitro, the heparin management test was analyzed for heparin levels between 0 and 6 IU/ml using variations in hematocrit, platelets, procoagulants, and storage time. The in vivostudies consisted of two groups: In group I (cardiopulmonary bypass </= 90 min, n = 40), anticoagulation was performed according to the activated clotting time (with or without aprotinin); in group II (cardiopulmonary bypass >/= 180 min, with aprotinin) included use (n = 10) and nonuse of coumadin (n = 10) and anticoagulation according to the automated heparin dose-response assay. Tests were performed in duplicate (whole blood, two heparin management test analyzers) and compared with anti-Xa activity (plasma). Results In vitro, the results of the heparin management test (n = 1,070) correlated well with heparin concentration (r2 = 0.98). Dilution and storage time did not affect the heparin management test; a hematocrit of 60% and reduced procoagulants (10%) prolonged clotting time. In vivo, the correlation (heparin management test vs. anti-Xa) was strong in group I (r2 = 0.97 [with aprotinin] and 0.96 [without aprotinin]; n = 960) and group II without coumadin (r2 = 0.89, n = 516). In group II with coumadin, the overall correlation was r2 = 0.87 and 0.79 (n = 484), although the range varied widely (0.57-0.94, between-analyzer differences 0-47%). Conclusions The results of the heparin management test were influenced by hematocrit, plasma coagulation factors, and the heparin level, but not by use of aprotinin. The heparin management test provided reliable values in vitro in group I, and in group II without coumadin but was less reliable in group II with coumadin.

Monitoring Activated Clotting Time for Combined Heparin and Aprotinin Application: An In Vitro Evaluation of a New Aprotinin-Insensitive Test Using SONOCLOT

2005 ◽  
Vol 101 (2) ◽  
pp. 308-314 ◽  
Author(s):  
Michael T. Ganter ◽  
Seraina Dalbert ◽  
Kirk Graves ◽  
Richard Klaghofer ◽  
Andreas Zollinger ◽  
...  
Keyword(s):  
Clotting Time ◽  
In Vitro Evaluation ◽  
Activated Clotting Time

scholarly journals In Vitro Microbiological Analysis of Bacterial Seal at the Implant-Abutment Interface Using Two Morse Taper Implant Models

2014 ◽  
Vol 25 (1) ◽  
pp. 48-53 ◽  
Author(s):  
Deceles Cristina Costa Alves ◽  
Paulo Sérgio Perri de Carvalho ◽  
Elizabeth Ferreira Martinez
Keyword(s):  
Brain Heart Infusion ◽  
The Other ◽  
Microbiological Analysis ◽  
Torque Wrench ◽  
Significant Difference ◽  
Implant Abutment ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

The objective of this study was to evaluate the bacterial seal at the implant-abutment interface using two morse taper implant models, by means of an in vitro microbiological analysis. For that were used 15 implants with mini-abutments tightened by friction, no screws (Group 1); and 30 implants with screw-tightened abutments, of which 15 received 20 N.cm of closing torque (Group 2) and the other 15 received 30 N.cm (Group 3). Microbiological analysis was carried out using colonies of Escherichia coli transported directly from a culture dish to the prosthetic component. Friction implants (Group 1) were activated by tapping and a torque wrench was used for screw-tightened implants (Groups 2 and 3). Each abutment/implant set was immersed in test tubes containing 5 mL of brain-heart infusion broth and incubated at 37 °C for 14 days, observed daily for the presence of contamination. A statistically significant difference was observed regarding the number of contaminated implants. There was greater contamination in Group 2 implants (p<0.05), with no statistically significant difference between the other groups (Group 1 = 20% and Group 3 = 0%). It was concluded that there was no significant difference in in vitro bacterial sealing between implants with mini-abutments tightened by friction without screws and implants with screw-tightened abutments with 30 N.cm of closing torque. The difference in closing torque altered the in vitro sealing ability of the tested abutments, with a greater contamination for components that received a closing torque of 20 N.cm.

Implementation of Vancomycin Monitoring Criteria in a Pediatric Hospital

2004 ◽  
Vol 9 (3) ◽  
pp. 179-186
Author(s):  
Kelley R. Lee ◽  
Stephanie J. Phelps
Keyword(s):  
Blood Cell ◽  
Serum Creatinine ◽  
White Blood Cell ◽  
Primary Objective ◽  
Serum Concentrations ◽  
Cell Counts ◽  
Group 2 ◽  
Serum Vancomycin ◽  
Group 1

OBJECTIVES The primary objective of this retrospective study was to determine if implementation of vancomycin monitoring criteria could reduce the number of serum vancomycin concentrations obtained without adversely affecting patient outcomes. BACKGROUND Controversy regarding the correlation between serum vancomycin concentrations and its efficacy and/or toxicity persists. Little evidence has shown a correlation between vancomycin peak concentration (20–40 mg/L) and toxicity. Likewise, there is little information that supports an association between trough (5–15 mg/L) serum concentrations and clinical cure or in vitro killing rates. For these reasons, many question the clinical utility and cost-effectiveness of monitoring serum vancomycin concentrations. METHODS We reviewed medical records of 193 patients (1 d-19 yrs) who received vancomycin during a 2-month period before (Group 1; n = 100) and after (Group 2; n = 93) implementation of vancomycin monitoring criteria. RESULTS There was no difference (P &gt; 0.05) in baseline age, weight, white blood cell count, temperature, serum creatinine, and blood urea nitrogen between Groups 1 and 2. Although 49.5% of all patients had vancomycin serum concentrations performed, significantly (P &lt; 0.005) fewer patients in Group 2 (32%) were monitored when compared to Group 1 (65%). Peak serum vancomycin concentrations were within the reference range (20–40 mg/L) in 48% of patients in Group 1 compared to 80% in Group 2 (P = 0.03). The mean duration of vancomycin therapy was greater (P = 0.004) for patients in Group 1 (7 ± 7.5 days) compared to Group 2 (4 ± 4.4 days) and the medians for the two groups were also different. Mean ending temperatures (P = 0.23), white blood cell counts (P = 0.71), serum creatinine (P = 0.3) and BUN (P = 0.24) were not different for the two groups. CONCLUSIONS Implementation of criteria to decrease unnecessary serum vancomycin concentration monitoring does not adversely affect patient outcome and may decrease cost to the institution, healthcare system, and patient.

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