scholarly journals Quality Control of Factor VIII Concentrates Using an Automated Device. A Long-Term Study

1977 ◽  
Author(s):  
T. Kirkwood ◽  
M. Miller-Andersson ◽  
M.J. Seghatchian
Keyword(s):  
Quality Control ◽  
Major Change ◽  
Assay Method ◽  
End Point ◽  
Long Term Study ◽  
Normal Plasma ◽  
Accuracy And Precision ◽  
Factor Viii Concentrates ◽  
Great Uniformity ◽  
The Right

A F VIII quality control system must allow accurate and uniformly precised measurements. Accuracy depend both on assay method and on reagents. The “right answer” to a F VIII:c is undefined, so we can only control internal accuracy of the assay system by demonstrating that the result is uneffected by changes from one batch of reagent to another. Precision is affected by several sources of error,(e.g. pipetting, measurement of end point etc.) Automation allows great uniformity of these. Accuracy and precision also depend on the reference plasma. It is well established that assays of concentrate against concentrate are less variable than assays of concentrate against plasma. In this study we collected data from quality control assays of 437 batches of concentrate against frozen normal plasma (–150°C). Each assay also contained a single batch of cryoprecipitate stored under equal conditions. The assays were performed over 60 weeks during which time 6 batches of substrate plasma 2 batches of Cephotest and 7 normal plasma pools were used. The lamp used for optical determination of the end point was also changed once. Statistical analysis showed that the only major change of the results occured when the normal plasmapools were changed. Otherwise the uniformity of the measurement was very good. The results strongly suggests the use of large batches of reference standards which may be calibrated against the international standard, and is preferable to the use of frozen normal plasma pools.

Friction-Instability: A New Design Parameter for Brakes

1971 ◽  
Vol 93 (4) ◽  
pp. 1225-1228 ◽  
Author(s):  
W. L. Starkey ◽  
T. G. Foster ◽  
S. M. Marco
Keyword(s):  
Quality Control ◽  
Coefficient Of Friction ◽  
Design Parameter ◽  
Control Device ◽  
Experimental Facility ◽  
Test Results ◽  
Effective Manner ◽  
The Coefficient Of Friction ◽  
Brake Lining ◽  
The Right

A new design parameter, friction-instability, is defined in this paper. Friction-instability is a variation in the coefficient of friction which may occur at any time during the life of a brake lining. A friction-index is defined which measures this variation. A lining which has a high friction index may tend to cause an automobile to swerve either to the right or to the left. A unique experimental facility is described by means of which the friction-instability characteristics of brake linings can be measured. Test results using this facility are presented and interpreted. The friction-index is proposed as a new parameter which should be taken into consideration when brakes are designed and, developed. This index should be particularly useful as a quality control device to insure that machines which use mass-produced braking systems will perform in a safe and effective manner.

Abstract 15388: Persistent Pulmonary Hypertension After Transcatheter Aortic Valve Implantation: Impact on Mortality

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Maria Drakopoulou ◽  
Konstantinos Stathogiannis ◽  
Konstantinos Toutouzas ◽  
George Latsios ◽  
Andreas Synetos ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Aortic Stenosis ◽  
Pulmonary Artery ◽  
Severe Aortic Stenosis ◽  
Systolic Pressure ◽  
Right Atrial ◽  
Pulmonary Artery Systolic Pressure ◽  
End Point ◽  
The Right ◽  
The Impact

Objective: Severe aortic stenosis leads to increased pulmonary arterial systolic pressure. A controversy still remains regarding the impact of persistent pulmonary hypertension (PHT) on prognosis of patients undergoing transcatheter aortic valve implantation (TAVI). We sought to investigate the impact of persistent PHT on 2-year all-cause mortality of patients with severe aortic stenosis following TAVI. Methods: Patients with severe and symptomatic aortic stenosis (effective orifice area [EOA]≤1 cm 2 ) who were scheduled for TAVI with a self-expanding valve at our institution were prospectively enrolled. Prospectively collected echocardiographic data before and after TAVI were retrospectively analyzed in all patients. Pulmonary artery systolic pressure was estimated as the sum of the right ventricular to the right atrial gradient during systole and the right atrial pressure. PHT following TAVI was classified as absent if <35 mmHg and persistent if ≥35 mmHg. Primary clinical end-point was 2-year all-cause mortality defined according to the criteria proposed by the Valve Academic Research Consortium-2. Results: Hundred and forty patients (mean age: 82±9 years) were included in the study. The primary clinical end point occurred in 17 patients (12%) during a median follow-up period of 2 years. Mean pulmonary artery systolic pressure was reduced in all patients following TAVI (45±9 versus 41±6 mmHg, p<0.01). Mortality rate was higher in patients with persistent PHT compared to patients with normal pulmonary artery systolic pressure following TAVI (26% versus 14 %, p<0.01). Patients that reached the primary clinical end point had a higher post procedural mean systolic pulmonary pressure (43±9 versus 39±6 mmHg, p=0.02). In multivariate regression analysis, persistence of PHT (OR: 2.51, 95% CI: 1.109-7.224, p=0.01) was an independent predictor of long-term mortality. Conclusions: The persistence of pulmonary hypertension after TAVI is associated with long term mortality. Identifying the population that will clearly benefit from TAVI is still need to be validated by larger trials.

scholarly journals Assay method for quality control and stability studies of a new antimalarial agent (CDRI 99/411)

2013 ◽  
Vol 3 (5) ◽  
pp. 335-340 ◽  
Author(s):  
Kiran Khandelwal ◽  
Shakti Deep Pachauri ◽  
Sofia Zaidi ◽  
Pankaj Dwivedi ◽  
Ashok Kumar Sharma ◽  
...  
Keyword(s):  
Quality Control ◽  
Assay Method ◽  
Stability Studies ◽  
Antimalarial Agent

Developing the Disruptors

2020 ◽  
pp. 23-40
Keyword(s):  
New Technologies ◽  
Deep Understanding ◽  
Major Change ◽  
Wicked Problems ◽  
Business Environment ◽  
Strategic Process ◽  
The Future ◽  
The Right ◽  
Current Business

Disruptive leaders possess a deep understanding of the nonobvious. Developing solutions with a heightened creativity, solving problems and addressing risks, finding the right tradeoffs, and recognizing the wicked opportunities in the wicked problems, disruptive leaders scan the environment, identify trends, and envision the future. Often, this is done by finding superior solutions, products, and services. However, this is done with a strategic process and plan. In our current business environment, right when we get comfortable, we find ourselves having to adjust to a major change that requires us to shift time, energy, and resources to solve a problem or stay ahead of the market, or change our market. Every change that we encounter creates winners and losers. If we are disruptive in our leadership, these changes can bring about fabulous innovation and create new technologies that benefit humankind. Building a disruptive organization is the best way to thrive. This chapter explores developing the disruptors.

Collaborative Study of Methods for the Analysis and Control of AG-Chlordane and Its Formulations

1973 ◽  
Vol 56 (3) ◽  
pp. 591-595
Author(s):  
Marshall A Malina
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Assay Method ◽  
Good Precision ◽  
Accuracy And Precision ◽  
Infrared Method ◽  
Gas Chromatographic Method ◽  
And Control ◽  
Excellent Accuracy

Abstract Four methods for the analysis of AG-chlordane and its formulations were submitted to a collaborative study. Fifteen laboratories, including 5 CIPAC laboratories, participated in this study. The infrared method for the analysis of the content of the 2 chlordane isomers was precise, with a coefficient of variation of 0.015. The gas chromatographic method for the analysis of the heptachlor content also yielded good precision with a standard deviation of 0.16. The infrared assay method for granular formulations exhibited excellent accuracy and precision, with a coefficient of variation of 0.067 and an error of only +0.25% relative. The gas chromatographic assay method for emulsifiable concentrates exhibited poor accuracy and precision and was found unacceptable. The first 3 methods have been adopted as official first action.

Quantitation of Plasma Aldosterone by Radioimmunoassay

1972 ◽  
Vol 18 (11) ◽  
pp. 1395-1402 ◽  
Author(s):  
M J St Cyr ◽  
J M Sancho ◽  
J C Melby
Keyword(s):  
Thin Layer ◽  
Upright Position ◽  
Plasma Aldosterone ◽  
Chromatographic System ◽  
Normal Plasma ◽  
Accuracy And Precision

Abstract Aldosterone antibodies were produced by injecting sheep with the albumin conjugate of aldosterone-18,21-dihemisuccinate. Conditions optimal for an accurate, reproducible assay with this antiserum were determined experimentally. Aldosterone is extracted from plasma and isolated by a single thin-layer chromatographic system before the immunoassay is performed. Normal plasma aldosterone in supine subjects is 8.6 ± 3.8 ng/100 ml; after 2 h in the upright position, 18.3 ± 9.5 ng/100 ml. Eighteen months of experience with the method have proved it to be reliable with respect to reproducibility, accuracy, and precision.

Comparative Investigations on Factor VIII Assays

1975 ◽  
Author(s):  
R. Pflugshaupt ◽  
S. Moser ◽  
K. Züger ◽  
R. Bütler
Keyword(s):  
Factor Viii ◽  
High Activity ◽  
Hemophilia A ◽  
Statistical Evaluation ◽  
Two Stage ◽  
One Stage ◽  
Normal Plasma ◽  
Calibration Curves ◽  
Factor Viii Concentrates

Six one stage methods and one two stage method were tested for precision and reproducibility. With each method twenty calibration curves of normal plasma and two lots of Factor VIII concentrates were established. Statistical evaluation revealed only minor differences. Neither one of the methods was optimal for both the physiological-pathological region and the region of high activity preparations.Three selected methods were tested in vivo for accuracy: nine patients with hemophilia A were treated with equal amounts of Factor VIII concentrates or kryoprecipitates respectively. The methods showed different activities for preparations as well as for patient’s plasma. The discrepancy between measured and expected recovery differed for each method.

Experiences with a gravity-assisted valve in hydrocephalic children

2009 ◽  
Vol 4 (3) ◽  
pp. 288-293 ◽  
Author(s):  
Ernst Johannes Haberl ◽  
Martina Messing-Juenger ◽  
Martin Schuhmann ◽  
Regina Eymann ◽  
Cornelia Cedzich ◽  
...  
Keyword(s):  
Complication Rate ◽  
Secondary Outcome ◽  
Csf Shunt ◽  
Early Complication ◽  
Valve Design ◽  
End Point ◽  
Pediatric Hydrocephalus ◽  
Long Term Study ◽  
Early Results

Object Over the past decade, a gravity-assisted valve (GAV) has become a standard device in many European pediatric hydrocephalus centers. Because past comparative clinical outcome studies on valve design have not included any GAV, the authors in this trial evaluated the early results of GAV applications in a pediatric population. Methods For a minimum of 2 years the authors monitored 169 of 182 hydrocephalic children who received a pediatric GAV at their first CSF shunt insertion (61.5%) or as a substitute for any differential pressure valve (38.5%) at 1 of 7 European pediatric hydrocephalus centers. Outcomes were categorized as valve survival (primary outcome) or shunt survival (secondary outcome). The end point was defined as valve explantation. Results Within a follow-up period of 2 years, the valve remained functional in 130 (76.9%) of 169 patients. One hundred eight of these patients (63.9%) had an uncomplicated clinical course without any subsequent surgery, and 22 (13%) were submitted to a valve-preserving catheter revision without any further complications during the follow-up period. Thirty-nine patients (23.1%) reached an end point of valve explantation: 13 valve failures from infection (7.7%), 8 (4.7%) from overdrainage, and 18 (10.6%) from underdrainage. Conclusions Compared with nongravitational shunt designs, a GAV does not substantially affect the early complication rate. Valve-preserving shunt revisions do not increase the risk of subsequent valve failure and therefore should not be defined as an end point in studies on valve design. A significant impact of any well-established valve design on the early complication rate in shunt surgery is not supported by any current data; therefore, this correlation should be dismissed. As overdrainage-related complications have been shown to occur late, the presumed advantages of a pediatric GAV remain to be shown in a long-term study.

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