MODERN AND RAPID METHODS FOR TOXICOLOGICAL ANALYSIS OF FOODSTUFFS WITH BACTERIAL CONTAMINATION

Foodborne illnesses are a widespread problem throughout the world. Food poisoning due to bacterial toxins can be caused by the ingestion of exotoxins which are preformed in the food, or by the ingestion of food containing large numbers of bacterial cells which then release endotoxins in the gastrointestinal tract. Early methods for the assay of bacteria toxins were based on in vivo or in vitro tests. Later, immunological tests were developed based on techniques such as gel diffusion. Different types of methods have been developed for the detection of toxin genes and their toxic products. These methods include the detection of toxin genes by amplification methods and hybridization probing. There are now a number of rapid test kits available which give results within hours and are much simpler to perform and interpret than bioassays.

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Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646468 ◽

1991 ◽

Vol 66 (05) ◽

pp. 609-613 ◽

Cited By ~ 14

Author(s):

I R MacGregor ◽

J M Ferguson ◽

L F McLaughlin ◽

T Burnouf ◽

C V Prowse

Keyword(s):

High Purity ◽

Time Course ◽

Prothrombin Complex Concentrate ◽

Degradation Products ◽

Canine Model ◽

Factor Ix ◽

In Vitro Tests ◽

Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

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A Comparison of the in Vitro and in Vivo Thrombogenic Activity of Factor IX Concentrates Using Stasis (Wessler) and Non-Stasis Rabbit Models

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650089 ◽

1980 ◽

Vol 44 (02) ◽

pp. 081-086 ◽

Cited By ~ 8

Author(s):

C V Prowse ◽

A E Williams

Keyword(s):

Platelet Rich Plasma ◽

Thrombus Formation ◽

Factor Ix ◽

Coagulation System ◽

In Vitro Tests ◽

Clinical Use ◽

Low Activity

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.

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Inhibition of Fibrinolysis and Fibrinogenolysis in Man: Comparison of ε-Aminocaproic Acid and Kallikrein Inhibitor

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660337 ◽

1963 ◽

Vol 10 (01) ◽

pp. 106-119 ◽

Cited By ~ 8

Author(s):

E Beck ◽

R Schmutzler ◽

F Duckert ◽

Keyword(s):

Aminocaproic Acid ◽

Side Reactions ◽

In Vitro Tests ◽

Factor V ◽

Clinical Use ◽

Strong Inhibitor ◽

Kallikrein Inhibitor ◽

Therapeutic Possibilities

SummaryInhibitor of kallikrein and trypsin (KI) extracted from bovine parotis was compared with ε-aminocaproic acid (EACA): both substances inhibit fibrinolysis induced with streptokinase. EACA is a strong inhibitor of fibrinolysis in concentrations higher than 0, 1 mg per ml plasma. The same amount and higher concentrations are not able to inhibit completely the proteolytic-side reactions of fibrinolysis (fibrinogenolysis, diminution of factor V, rise of fibrin-polymerization-inhibitors). KI inhibits well proteolysis of plasma components in concentrations higher than 2,5 units per ml plasma. Much higher amounts of KI are needed to inhibit fibrinolysis as demonstrated by our in vivo and in vitro tests.Combination of the two substances for clinical use is suggested. Therapeutic possibilities are discussed.

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Role of in vivo and in vitro Tests in the Diagnosis of Severe Cutaneous Adverse Reactions (SCAR) to Drug

Current Pharmaceutical Design ◽

10.2174/1381612825666191107104126 ◽

2019 ◽

Vol 25 (36) ◽

pp. 3872-3880 ◽

Cited By ~ 3

Author(s):

Marcel M. Bergmann ◽

Jean-Christoph Caubet

Keyword(s):

Adverse Reactions ◽

Lymphocyte Transformation ◽

Stevens Johnson Syndrome ◽

In Vitro Tests ◽

High Morbidity ◽

Patch Tests ◽

Severe Cutaneous Adverse Reactions ◽

Cutaneous Adverse Reactions

Severe cutaneous adverse reactions (SCAR) are life-threatening conditions including acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Diagnosis of causative underlying drug hypersensitivity (DH) is mandatory due to the high morbidity and mortality upon re-exposure with the incriminated drug. If an underlying DH is suspected, in vivo test, including patch tests (PTs), delayed-reading intradermal tests (IDTs) and in vitro tests can be performed in selected patients for which the suspected culprit drug is mandatory, or in order to find a safe alternative treatment. Positivity of in vivo and in vitro tests in SCAR to drug varies depending on the type of reaction and the incriminated drugs. Due to the severe nature of these reactions, drug provocation test (DPT) is highly contraindicated in patients who experienced SCAR. Thus, sensitivity is based on positive test results in patients with a suggestive clinical history. Patch tests still remain the first-line diagnostic tests in the majority of patients with SCAR, followed, in case of negative results, by delayed-reading IDTs, with the exception of patients with bullous diseases where IDTs are still contra-indicated. In vitro tests have shown promising results in the diagnosis of SCAR to drug. Positivity is particularly high when the lymphocyte transformation test (LTT) is combined with cytokines and cytotoxic markers measurement (cyto-LTT), but this still has to be confirmed with larger studies. Due to the rarity of SCAR, large multi-center collaborative studies are needed to better study the sensitivity and specificity of in vivo and in vitro tests.

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Hemostatic wound dressings: Predicting their effects by in vitro tests

Journal of Biomaterials Applications ◽

10.1177/0885328219831095 ◽

2019 ◽

Vol 33 (9) ◽

pp. 1285-1297 ◽

Cited By ~ 2

Author(s):

Cornelia Wiegand ◽

Martin Abel ◽

Uta-Christina Hipler ◽

Peter Elsner ◽

Michael Zieger ◽

...

Keyword(s):

Blood Clot ◽

Wound Dressings ◽

In Vitro Tests ◽

Regenerated Cellulose ◽

Oxidized Regenerated Cellulose ◽

Inflammatory Reactions ◽

In Vitro Techniques ◽

Cotton Gauze

Background Application of controlled in vitro techniques can be used as a screening tool for the development of new hemostatic agents allowing quantitative assessment of overall hemostatic potential. Materials and methods Several tests were selected to evaluate the efficacy of cotton gauze, collagen, and oxidized regenerated cellulose for enhancing blood clotting, coagulation, and platelet activation. Results Visual inspection of dressings after blood contact proved the formation of blood clots. Scanning electron microscopy demonstrated the adsorption of blood cells and plasma proteins. Significantly enhanced blood clot formation was observed for collagen together with β-thromboglobulin increase and platelet count reduction. Oxidized regenerated cellulose demonstrated slower clotting rates not yielding any thrombin generation; yet, led to significantly increased thrombin-anti-thrombin-III complex levels compared to the other dressings. As hemostyptica ought to function without triggering any adverse events, induction of hemolysis, instigation of inflammatory reactions, and initiation of the innate complement system were also tested. Here, cotton gauze provoked high PMN elastase and elevated SC5b-9 concentrations. Conclusions A range of tests for desired and undesired effects of materials need to be combined to gain some degree of predictability of the in vivo situation. Collagen-based dressings demonstrated the highest hemostyptic properties with lowest adverse reactions whereas gauze did not induce high coagulation activation but rather activated leukocytes and complement.

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Animal Models and Alternatives in the Quality Control of Vaccines: Are In Vitro Methods or In Vivo Methods the Scientific Equivalent of the Emperor's New Clothes?

Alternatives to Laboratory Animals ◽

10.1177/026119299502300110 ◽

1995 ◽

Vol 23 (1) ◽

pp. 61-73

Author(s):

Coenraad Hendriksen ◽

Johan van der Gun

Keyword(s):

Quality Control ◽

Test Methods ◽

In Vitro Test ◽

Large Numbers ◽

Alternative Approach ◽

Inactivated Vaccines ◽

Vitro Test

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.

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Human Saliva-Mediated Hydrolysis of Eugenyl-β-D-Glucoside and Fluorescein-di-β-D-Glucoside in In Vivo and In Vitro Models

Biomolecules ◽

10.3390/biom11020172 ◽

2021 ◽

Vol 11 (2) ◽

pp. 172

Author(s):

Mariusz Dziadas ◽

Adam Junka ◽

Henryk Jeleń

Keyword(s):

Oral Cavity ◽

Control Sample ◽

Rapid Test ◽

Human Saliva ◽

In Vitro Models ◽

Microbial Hydrolysis ◽

Amoxicillin Trihydrate ◽

Potassium Clavulanate

Eugenyl-β-D-glucopyranoside, also referred to as Citrusin C, is a natural glucoside found among others in cloves, basil and cinnamon plants. Eugenol in a form of free aglycone is used in perfumeries, flavourings, essential oils and in medicinal products. Synthetic Citrusin C was incubated with human saliva in several in vitro models together with substrate-specific enzyme and antibiotics (clindamycin, ciprofloxacin, amoxicillin trihydrate and potassium clavulanate). Citrusin C was detected using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Citrusin C was completely degraded only when incubated with substrate-specific A. niger glucosidase E.C 3.2.1.21 (control sample) and when incubated with human saliva (tested sample). The addition of antibiotics to the above-described experimental setting, stopped Citrusin C degradation, indicating microbiologic origin of hydrolysis observed. Our results demonstrate that Citrusin C is subjected to complete degradation by salivary/oral cavity microorganisms. Extrapolation of our results allows to state that in the human oral cavity, virtually all β-D-glucosides would follow this type of hydrolysis. Additionally, a new method was developed for an in vivo rapid test of glucosidase activity in the human mouth on the tongue using fluorescein-di-β-D-glucoside as substrate. The results presented in this study serve as a proof of concept for the hypothesis that microbial hydrolysis path of β-D-glucosides begins immediately in the human mouth and releases the aglycone directly into the gastrointestinal tract.

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Activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum (Cestoda: Pseudophyllidea)

Parasitology ◽

10.1017/s0031182000085243 ◽

1981 ◽

Vol 83 (2) ◽

pp. 243-247 ◽

Cited By ~ 24

Author(s):

Margaretha K. S. Gustafsson ◽

Marianne C. Wikgren

Keyword(s):

Neurosecretory Cells ◽

Final Host ◽

Fish Host ◽

Neurosecretory System ◽

Weak Reaction ◽

Diphyllobothrium Dendriticum ◽

Large Numbers ◽

Short Times

SUMMARYThe activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum was studied following cultivation of plerocercoids for short times in vitro and in vivo. In the plerocercoid the neurosecretory cells gave a very weak reaction with paraldehyde fuchsin (PAF). After cultivation for 1 h large numbers of neurosecretory cells filled with PAF-positive granules were evident. The significance of the activation of the neurosecretory system during the transfer of the worm from the cold-blooded fish host to the warm-blooded final host is discussed.

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In Vitro Methods as a Tool in Neurotoxicity Studies

Alternatives to Laboratory Animals ◽

10.1177/026119299502300412 ◽

1995 ◽

Vol 23 (4) ◽

pp. 491-496

Author(s):

Hanna Tähti ◽

Leila Vaalavirta ◽

Tarja Toimela

Keyword(s):

Risk Evaluation ◽

Toxicity Testing ◽

In Vitro Models ◽

In Vitro Tests ◽

Industrial Chemicals ◽

Mercury Compounds ◽

Toxicological Data ◽

In Vivo Tests

— 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.

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