Misleading conclusions on effects of resistant starch due to inappropriate formulation of controls, inadequate statistical power, and anomalies in the in vitro methods

SummaryThe activity of several synthetic compounds, rated from good to poor (or inactive) fibrinolytic activators, has been assessed by two different commonly-used in vitro methods. Compounds shown to be active over a narrow concentration range in the hanging clot test were shown to be inhibitors of plasmin and trypsin in the casein-olytic test. The inhibitory activity of these compounds was shown to increase with increasing substrate concentration and apparent activity in the hanging clot test. Possible explanations and relevance of these observations are discussed.

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PREPARATION AND CHARACTERISATION OF ACETYLATED WHEAT STARCH SUPPORTING FOR DIABETES TREATMENT

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2018.5.11 ◽

2018 ◽

Vol 8 (5) ◽

pp. 78-84

Author(s):

Uyen Tran Thi Ngoc ◽

Nam Nguyen Khac ◽

Dung Tran Huu

Keyword(s):

Physicochemical Properties ◽

Resistant Starch ◽

Starch Content ◽

Degree Of Substitution ◽

Wheat Starch ◽

Diabetes Treatment ◽

Glucose Response ◽

Swelling Capacity ◽

Wheat Starches

Background: The purpose of the study was to prepare acetylated wheat starches which have amylase hydrolysis resistant capacity to use as functional food supporting for diabetes treatment. Method: Acetate wheat starches were prepared by acetylation reaction of native wheat starch with different mole ratios of acetic anhydride. These starches were determined for the physicochemical properties by 1H-NMR, SEM, X-ray, DSC, solubility and swelling capacity, the resistant capacity by amylase hydrolysis in-vitro. Results: Acetate wheat starches were prepared successfully with the increase in acetyl content and degree of substitution corresponding with the increase of anhydride acetic, which resulted in the change of physicochemical properties of the wheat starches, including constitution, solubility, swelling capacity and contributed to the increase in resistant starch content in the acetate wheat starches. The AC150-9 containing 2.42% acetyl with degree of substitution 0,094 and resistant starch 32,11% is acceptable by FDA guideline about food safety. Conclusion: Acetate wheat starches contain low rate of digestive starch, while containing a higher proportion of resistant starch than natural wheat starch, possessing a high resistance to amylase activities. Thus, it is hope that this kind of starch to control the rapid increase of postprandual blood glucose response for diabetes treatments effectively. Key words: Acetate wheat starch, substitution, DS, RS, amylase

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A Call for a European Prohibition of Monoclonal Antibody Production by the Ascites Procedure in Laboratory Animals

Alternatives to Laboratory Animals ◽

10.1177/026119299802600414 ◽

1998 ◽

Vol 26 (4) ◽

pp. 523-536

Author(s):

Coenraad F.M. Hendriksen

Keyword(s):

Monoclonal Antibody ◽

Laboratory Animals ◽

Induction Method ◽

Therapeutic Application ◽

Monoclonal Antibody Production ◽

In Vitro Methods ◽

Appeals Process ◽

Core Facilities ◽

Mab Production

Monoclonal antibodies (mAbs) are particularly valuable in therapeutics and research. Unfortunately, one of the most familiar methods of producing mAbs, the ascites induction method, causes pain and distress to the animals used. In most cases, non-animal or in vitro alternatives can be employed to reduce or eliminate the use of animals for mAb production. Prohibition of the use of animals in the production of mAbs is recommended, except when the replacement in vitro methods prove to be insufficient, and in a limited number of other well-documented cases, such as an exceptional need for an emergency therapeutic application. A total ban on the use of animals for mAb production is impractical and it is imperative that an appeals process should accompany the prohibition. The need for the establishment of core facilities for in vitro mAb production is emphasised.

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In Vitro Methods for the Assessment of L-Cysteine Conjugate Toxicity

Alternatives to Laboratory Animals ◽

10.1177/026119299402200203 ◽

1994 ◽

Vol 22 (2) ◽

pp. 72-80

Author(s):

Lorraine D. Buckberry ◽

Harriet J. Adcock ◽

Jeremy Adler ◽

Ian S. Blagbrough ◽

Peter J. Gaskin ◽

...

Keyword(s):

Mechanism Of Action ◽

Mammalian Species ◽

Mercapturic Acid ◽

Assay Method ◽

Cellular Toxicity ◽

In Vitro Methods ◽

Metabolic Route ◽

Assay Methods ◽

Chang Liver

L-Cysteine conjugates are normally metabolised via N-acetylation to produce a mercapturic acid. However, a recently identified metabolic route (C-S lysis) may lead to the generation of an unstable thiol which has been demonstrated to be responsible for toxicity in various mammalian species. Human Chang liver cells were challenged with a number of established L-cysteine conjugates. The cellular toxicity of these compounds was determined using a range of assay procedures, which provided differing information, depending on the assay method used. These observations were then investigated in order to establish which system would provide the most reliable indication of C-S lyase toxicity and whether any information on the mechanism of action could be obtained by these assay methods.

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In Vitro Toxicology Methods in Risk Assessment

Alternatives to Laboratory Animals ◽

10.1177/026119299602400305 ◽

1996 ◽

Vol 24 (3) ◽

pp. 325-331

Author(s):

Iain F. H. Purchase

Keyword(s):

Risk Assessment ◽

Hazard Assessment ◽

Human Health Risk ◽

In Vitro Test ◽

In Vitro Methods ◽

New Concepts ◽

Vitro Test

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.

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Semen Cuscutae-Fructus Lycii improves spermatogenic dysfunction by repairing the blood-testis barrier in rats according to in silico and in vitro methods

Journal of Ethnopharmacology ◽

10.1016/j.jep.2021.114022 ◽

2021 ◽

pp. 114022

Author(s):

Yutian Zhu ◽

Lei Dong ◽

Jingshang Wang ◽

Qiuning Liu ◽

Hongxuan Tong ◽

...

Keyword(s):

In Silico ◽

In Vitro Methods ◽

Fructus Lycii ◽

Blood Testis Barrier

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Studies of Metabolism Mediated Mutagenicity In Vitro

Alternatives to Laboratory Animals ◽

10.1177/026119299001800124.1 ◽

1990 ◽

Vol 18 (1_part_1) ◽

pp. 243-250

Author(s):

Dag Jenssen ◽

Lennart Romert

Keyword(s):

Cell Lines ◽

Biological Effects ◽

Animal Experiments ◽

Culture Technique ◽

Organ Perfusion ◽

Isolated Cells ◽

Toxicological Effect ◽

In Vitro Methods

To understand the cause of the biological effects of xenobiotic metabolism in mammals, investigators have traditionally performed animal experiments by comparing the results of biochemical methods, such as measurement of enzyme activity analysis of the metabolites produced, with the observed toxicological effect. This article deals with in vitro methods for genotoxicity combined with drug metabolising preparations at the organelle, cell or organ levels, as exemplified by microsome preparations, isolated cells/cell lines and organ perfusion systems, respectively. The advantage of some of these methods for studying metabolism-mediated mutagenicity is that the measured endpoint reflects not only the bioactivating phase I reactions, but also the detoxifying phase II reactions, and the transfer of the non-conjugated reactive metabolites to other cells and their ability to cause mutations in these cells. In vivo, all these events are important factors in the initiation of cancer. A mechanistic advantage of the methods for metabolism-mediated mutagenicity in vitro is that the relevance of the different steps in metabolism for the mutational events can seldom be investigated in an in vivo assay. Furthermore, human studies can easily be performed using the co-culture technique with isolated human cells or cell lines.

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