Optimisation and pre-validation of an in Vitro test strategy for predicting human acute toxicity: Progress of the “A-Cute-Tox” project

In order to evaluate the relevance of in vitro test systems for acute toxicity assessment, quantitative comparisons of in vitro and in vivo potency data have to be performed. The potency of chemicals to cells in vitro is usually characterised by nominal effective concentrations (e.g. EC50 values). Often, the only available in vivo data are acute lethal body doses (e.g. LD50 values). To enable a reasonable quantitative in vitro–in vivo comparison to be made, a formula has been developed to permit the conversion of EC50 values into “effective model body doses, ED50 values”. This formula takes into account the lipophilicity of the compounds and the very different relationships between the volumes of the lipid and water compartments in vitro and in vivo. The suitability of this approach is evaluated with results obtained for the first 30 MEIC chemicals.

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Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650069 ◽

1980 ◽

Vol 44 (01) ◽

pp. 006-008 ◽

Cited By ~ 12

Author(s):

D Bergqvist ◽

K-E Arfors

Keyword(s):

Whole Blood ◽

Platelet Rich Plasma ◽

Adenosine Diphosphate ◽

In Vitro Test ◽

Pharmacological Agents ◽

Vitro Test ◽

Releasing Effect ◽

Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

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IFN-.GAMMA. Production in Peripheral Lymphocytes from Patients with Drug Eruptions in Response to Stimulation with a Causative Drug. A New in vitro Test for Determining the Causative Drug in Drug Eruptions.

Nishi Nihon Hifuka ◽

10.2336/nishinihonhifu.59.859 ◽

1997 ◽

Vol 59 (6) ◽

pp. 859-863 ◽

Cited By ~ 1

Author(s):

Yukiko NONAKA ◽

Tetsuya KOGA ◽

Shoji TOSHITANI

Keyword(s):

In Vitro Test ◽

Ifn Gamma ◽

Peripheral Lymphocytes ◽

Drug Eruptions ◽

Causative Drug ◽

Vitro Test

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In Vitro Newly Isolated Environmental Phage Activity against Biofilms Preformed by Pseudomonas aeruginosa from Patients with Cystic Fibrosis

Microorganisms ◽

10.3390/microorganisms9030478 ◽

2021 ◽

Vol 9 (3) ◽

pp. 478

Author(s):

Ersilia Vita Fiscarelli ◽

Martina Rossitto ◽

Paola Rosati ◽

Nour Essa ◽

Valentina Crocetta ◽

...

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Multidrug Resistant ◽

In Vitro Test ◽

Chronic Infections ◽

Hospital Environments ◽

Vitro Test ◽

General Reliability ◽

Phage Activity

As disease worsens in patients with cystic fibrosis (CF), Pseudomonas aeruginosa (PA) colonizes the lungs, causing pulmonary failure and mortality. Progressively, PA forms typical biofilms, and antibiotic treatments determine multidrug-resistant (MDR) PA strains. To advance new therapies against MDR PA, research has reappraised bacteriophages (phages), viruses naturally infecting bacteria. Because few in vitro studies have tested phages on CF PA biofilms, general reliability remains unclear. This study aimed to test in vitro newly isolated environmental phage activity against PA isolates from patients with CF at Bambino Gesù Children’s Hospital (OBG), Rome, Italy. After testing in vitro phage activities, we combined phages with amikacin, meropenem, and tobramycin against CF PA pre-formed biofilms. We also investigated new emerging morphotypes and bacterial regrowth. We obtained 22 newly isolated phages from various environments, including OBG. In about 94% of 32 CF PA isolates tested, these phages showed in vitro PA lysis. Despite poor efficacy against chronic CF PA, five selected-lytic-phages (Φ4_ZP1, Φ9_ZP2, Φ14_OBG, Φ17_OBG, and Φ19_OBG) showed wide host activity. The Φ4_ZP1-meropenem and Φ14_OBG-tobramycin combinations significantly reduced CF PA biofilms (p < 0.001). To advance potential combined phage-antibiotic therapy, we envisage further in vitro test combinations with newly isolated phages, including those from hospital environments, against CF PA biofilms from early and chronic infections.

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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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