Comparison of methods for measurement of the pressure exerted by knitted fabrics

2016 ◽  
Vol 87 (17) ◽  
pp. 2117-2126 ◽  
Author(s):  
Małgorzata Cieślak ◽  
Agnieszka Karaszewska ◽  
Ewa Gromadzińska ◽  
Izabela Jasińska ◽  
Irena Kamińska

The article presents the results of measurements of pressure exerted by two model knitted products – bands with different structure (WI jersey weft-knitted fabric and WII openwork warp-knitted fabric). The tests were carried out with using the I-Scan system (in vivo and in vitro tests) and the STM 579 device (in vitro test). A comparative analysis of the in vivo and in vitro results for the I-Scan method and in vitro results for the I-Scan and STM 579 method was performed. It was found that the pressure values are lower for openwork warp-knitted fabric than for jersey weft-knitted fabric both in the case of the in vitro and in vivo tests, and the values of pressure for the same band are higher in the case of the in vitro tests.


1996 ◽  
Vol 24 (3) ◽  
pp. 435-438
Author(s):  
Kimmo Louekari

Ethical, economical and scientific considerations should encourage the development of alternative and in vitro test methods. Before their adoption, in vitro methods need to be validated and scientifically justified. Demand for rigorous validation schemes for in vitro tests must be emphasised, even more than in the case of in vivo tests. The OECD has adopted in vitro guidelines for testing genotoxicity; several endpoints and mechanisms can be studied in a cost-effective manner in vitro. Similar advantages could be afforded if acute irritation and corrosion, as well as the non-genotoxic carcinogenic effects of chemicals, could be studied in vitro. Evaluation of the validation status of various methods used to study non-genotoxic carcinogens was begun by the Nordic Working Group on In Vitro Methods for Non-genotoxic Mechanisms in 1996. In some established OECD test guidelines (for example, the dermal irritation/corrosion test), there is already room for the application of in vitro methods which have not been formally validated. In January 1996, the OECD Workshop on Harmonisation of Validation and Acceptance Criteria for Alternative Toxicological Test Methods set the basis for internationally acceptable principles to be followed in the validation of in vitro test methods.



1990 ◽  
Vol 18 (1_part_1) ◽  
pp. 11-18 ◽  
Author(s):  
Oliver P. Flint

The fullest potential for in vitro evaluation of toxicity will be realised in the context of the process of assessing the risk of human toxicity. This article is an attempt to clarify what contributions can be made by in vitro tests and what types of in vitro test can best be used. In vitro tests are clarified according to the type of biological endpoint evaluated, first into tests for general (‘basal’) cytotoxicity and, secondly, into tests for differentiated cell function. The role of each type of test is analysed and it is suggested that tests for general cytotoxicity, as opposed to differentiated function, are difficult to interpret in terms of in vivo toxicity. A general approach to evaluating in vitro tests is described, and a strategy for using these tests is proposed.



1998 ◽  
Vol 36 (1) ◽  
pp. 243-247 ◽  
Author(s):  
Jean Bickii ◽  
Leonardo K. Basco ◽  
Pascal Ringwald

Three in vitro assays (the isotopic semimicrotest [700 μl per well; 24-well plates], the isotopic microtest [200 μl per well; 96-well plates], and the rapid in vitro test) and the standard in vivo test for chloroquine resistance were compared for 99 clinical isolates of Plasmodium falciparum obtained from symptomatic African patients. The 50% inhibitory concentrations determined by the two isotopic tests were similar and were highly correlated (r = 0.965; P < 0.05), showing a high concordance between the semimicrotest and the microtest. There was a moderate agreement between these two isotopic tests and the in vivo test. Most of the discordant results were probably due to host factors, including reinfections, pharmacokinetic variations, and immunologic response, which are eliminated in in vitro assays. The rapid in vitro test based on the inhibition of chloroquine efflux in the presence of verapamil was poorly concordant with the other tests. Despite some discordant results, isotopic in vitro assays are useful to characterize the phenotypes of individual isolates without the interference of host factors and are complementary to in vivo evaluation of drug efficacy. However, in vitro assays need to be standardized to allow direct comparison of results between different laboratories.



1996 ◽  
Vol 24 (3) ◽  
pp. 325-331
Author(s):  
Iain F. H. Purchase

The title of this paper is challenging, because the question of how in vitro methods and results contribute to human health risk assessment is rarely considered. The process of risk assessment usually begins with hazard assessment, which provides a description of the inherent toxicological properties of the chemical. The next step is to assess the relevance of this to humans, i.e. the human hazard assessment. Finally, information on exposure is examined, and risk can then be assessed. In vitro methods have a limited, but important, role to play in risk assessment. The results can be used for classification and labelling; these are methods of controlling exposure, analogous to risk assessment, but without considering exposure. The Ames Salmonella test is the only in vitro method which is incorporated into regulations and used widely. Data from this test can, at best, lead to classification of a chemical with regard to genotoxicity, but cannot be used for classification and labelling on their own. Several in vitro test systems which assess the topical irritancy and corrosivity of chemicals have been reasonably well validated, and the results from these tests can be used for classification. The future development of in vitro methods is likely to be slow, as it depends on the development of new concepts and ideas. The in vivo methods which currently have reasonably developed in vitro alternatives will be the easiest to replace. The remaining in vivo methods, which provide toxicological information from repeated chronic dosing, with varied endpoints and by mechanisms which are not understood, will be more difficult to replace.



1995 ◽  
Vol 23 (1) ◽  
pp. 61-73
Author(s):  
Coenraad Hendriksen ◽  
Johan van der Gun

In the quality control of vaccine batches, the potency testing of inactivated vaccines is one of the areas requiring very large numbers of animals, which usually suffer significant distress as a result of the experimental procedures employed. This article deals with the potency testing of diphtheria and tetanus toxoids, two vaccines which are used extensively throughout the world. The relevance of the potency test prescribed by the European Pharmacopoeia monographs is questioned. The validity of the potency test as a model for the human response, the ability of the test to be standardised, and the relevance of the test in relation to the quality of the product are discussed. It is concluded that the potency test has only limited predictive value for the antitoxin responses to be expected in recipients of these toxoids. An alternative approach for estimating the potency of toxoid batches is discussed, in which a distinction is made between estimation of the immunogenic potency of the first few batches obtained from a seed lot and monitoring the consistency of the quality of subsequent batches. The use of animals is limited to the first few batches. Monitoring the consistency of the quality of subsequent batches is based on in vitro test methods. Factors which hamper the introduction and acceptance of the alternative approach are considered. Finally, proposals are made for replacement, reduction and/or refinement (the Three Rs) in the use of animals in the routine potency testing of toxoids.



1995 ◽  
Vol 23 (4) ◽  
pp. 491-496
Author(s):  
Hanna Tähti ◽  
Leila Vaalavirta ◽  
Tarja Toimela

— There are several hundred industrial chemicals with neurotoxic potential. The neurotoxic risks of most of these chemicals are unknown. Additional methods are needed to assess the risks more effectively and to elucidate the mechanisms of neurotoxicity more accurately than is possible with the conventional methods. This paper deals with general tasks concerning the use of in vitro models in the evaluation of neurotoxic risks. It is based on our previous studies with various in vitro models and on recent literature. The induction of glial fibrillary acidic protein in astrocyte cultures after treatment with known neurotoxicants (mercury compounds and aluminium) is discussed in more detail as an important response which can be detected in vitro. When used appropriately with in vivo tests and with previous toxicological data, in vitro neurotoxicity testing considerably improves risk assessment. The incorporation of in vitro tests into the early stages of risk evaluation can reduce the number of animals used in routine toxicity testing, by identifying chemicals with high neurotoxic potential.



2020 ◽  
Vol 98 (4) ◽  
pp. 48-52
Author(s):  
E. P. Eremenko ◽  
E. A. Borodulina ◽  
I. A. Sergeeva ◽  
D. A. Kudlay ◽  
B. E. Borodulin

In addition to standard skin tests (Mantoux test with 2 TU PPD-L and diaskintest) for the diagnosis of tuberculosis infection, in vitro tests are used. One of these tests is T-SPOT.TB being more widely used in recent years.The objective: to evaluate the effectiveness of T-SPOT.TB test for early detection of tuberculosis infection in children and adolescents in Samara Region.Subjects and methods. From 2016 to 2019, results of T-SPOT.TB tests performed in 596 children aged 2 to 17 years inclusive were analyzed; those children had no immunodiagnosis of tuberculosis infection using skin tests since their parents refused to have it.Results. It was found out that the major reason for refusing skin tests was the “fear” of visiting a TB dispensary if the result had been positive — 38.43% (n = 229). The latent tuberculosis infection according to the results of T-SPOT.TB among children with concomitant pathology made 2.6%, among healthy children – 0.7%.Conclusion. T-SPOT.TB test may be used as an alternative method for diagnosis of tuberculosis infection, should the parent refuse to have skin tests. In children with concomitant pathology, T-SPOT.TB test can serve as a leading method for immunodiagnosis of tuberculosis.The authors state that they have no conflict of interests.



AgriPeat ◽  
2019 ◽  
Vol 20 (02) ◽  
pp. 107-113
Author(s):  
Admin Journal

ABSTRACTThis study aims to determine the inhibition of eugenol derived from fractionation clove leaf essentialoils (CLEO) on the growth of pathogenic fungus Fusarium oxysporum f. sp. cubense (Foc) and LC50(Lethal Concentration 50). This research was in vitro, started with purification of clove leaf essentialoil, fractionation by vacuum distillation and bioassay. In vitro tests include exploration of minimuminhibition and preventability tests. Data were analyzed with Microsoft Excel 2010 program. Theresults of minimum inhibition showed at 218,75 ppm concentration of each level was able to inhibitthe growth of Foc fungi. The minimum inhibition exploration was carried out at 218,75 ppm, 109,38ppm, 54,69 ppm and 27,34 ppm. Exploration results showed that fractionated CLEO has been able toinhibit the growth of Foc fungi at 27,34 ppm in the amount of 15,60%. This concentration is used asthe lowest concentration in the inhibitory test. Furthermore, the inhibitory test was carried out startingat the highest concentration of 218,75 ppm, 109,38 ppm, 54,69 ppm and 27,34 ppm. Observationswere made for 7 days after inoculation (DAI). The results showed the best inhibition was at aconcentration of 218,75 ppm at 90,70% and LC50 at 11.17 µL.Keywords: CLEO, fractionation, Foc, in vitro test and LC50



2019 ◽  
Vol 9 (15) ◽  
pp. 3066 ◽  
Author(s):  
Emmanuel Reginald Jacques ◽  
Paschalis Alexandridis

Oral solid dosage formulations and/or tablets have remained the preferred route of administration by both patients and health care practitioners. Oral tablets are easy to administer, they are non-invasive and cause less risk adversity. Because of the lack of commercially available tablet dose options, tablets are being split or partitioned by users. Tablet scoring refers to the breakage of a tablet to attain a desired efficacy dose and is an emerging concept in the pharmaceutical industry. The primary reason for the tablet scoring practice is to adjust the dose: dose tapering or dose titrating. Other reasons for tablet partitioning are to facilitate dose administration, particularly among the pediatric and the geriatric patient population, and to mitigating the high cost of prescription drugs. The scope of this review is to: (1) evaluate the advantages and inconveniences associated with tablet scoring/portioning, and (2) identify factors in the formulation and the manufacturing of tablets that influence tablet splitting. Whereas tablet partitioning has been a common practice, there is a lack of understanding regarding the fundamentals underpinning the performance of tablets with respect to splitting. Several factors can influence tablet partitioning: tablet size, shape, and thickness. A requirement has recently been set by the European Pharmacopoeia and the U.S. Food and Drug Administration for the uniformity of mass of subdivided tablets. For breaking ease, an in-vivo reference test and a routinely applicable in-vitro test need to be established.



2016 ◽  
Vol 720 ◽  
pp. 130-140
Author(s):  
Berrak Bulut ◽  
Ziya Engin Erkmen ◽  
Eyup Sabri Kayali

Hydroxyapatite (HA) is a very popular bioceramic for orthopedic and dental applications. Although HA has excellent biocompatibility, its inferior mechanical properties make it unsuitable for load-bearing implant applications. Therefore, HA should be strengthened by a secondary phase for robust mechanical properties. The aim of this study was to compare the properties of HA-Al2O3 (HAC) and HA-ZrO2 (HZC) composites with the addition of 5 and 10 wt% commercial inert glass (CIG); independently. The mixture powders were pressed and then, the pellets were sintered between 1000-1300 °C for 4 hours. Microstructural characterizations were carried out using SEM + EDS and XRD, while hardness and compression tests were done to measure mechanical properties. In order to investigate the biocompatibility behavior of the samples in vitro and in vivo tests were performed. The mechanical properties of HAC composites increased with rising CIG content and increasing sintering temperature. For HZC composites, increasing CIG content caused an elevation in hardness and a decrease in compressive strength values at 1300 °C. The composites having the best physical and mechanical properties also showed improved bioactive properties at in vitro test. In this study, the ideal composite was selected as HZC5 sintered at 1200 °C depending on the microstructure, mechanical and biocompatibility properties.



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