bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hepatoma Cell Cultures as In Vitro Models for the Hepatotoxicity of Xenobiotics
Authors: Ferro Margherita , Bassi Anna Maria , Nanni Giorgio 
Published: August 2020

Two hepatoma cell cultures were examined as in vitro models to be used in genotoxicity and cytotoxicity tests without the addition of bioactivating enzymes. The MH1C1, and HTC hepatoma lines were used in this study to establish their sensitivity to a number of xenobiotics, namely, cyclophosphamide (CP), the classical positive control in bioactivation tests; benzaldehyde (BA), a short-chain aldehyde; and 4-hydroxynonenal (HNE), a major toxic end-product of the peroxidative degradation of cell membrane lipids. As a first approach, we compared the following cytotoxicity tests: release of lactate dehydrogenase (LDH), and colony formation efficiency (CF). Colony-forming cells were exposed to the drugs according to different procedures, before or after the anchorage phase. The leakage of LDH into the medium following exposure of both cell lines to HNE, CP and BA for up to 24 hours was found not to be a good index of cytotoxicity. A better indicator of cytotoxicity was CF, as evaluated by exposure of the cells 24 hours after seeding. The effects were detectable at very low concentrations, corresponding to 10, 90 and 100μM for HNE, CP and BA, respectively. The impairment of CF efficiency was dose-dependent and time-dependent, and several differences between the two cell lines were observed.
Lead Interference in Actin Redistribution Induced by Chemotactic Peptide in Human Neutrophils
Authors: Governa Mario , Visonà Isabella , Valentino Matteo , Marchiseppe Isabella 
Published: August 2020

The distribution of actin-containing structures in vitro was determined by fluorescence microscopy in human neutrophils exposed to two final concentrations of lead, 14.4μM and 28.8μM, stimulated with 10-8M formyl methyonylleucylphenylalanine (F-MLP) for either 45 seconds or 10 minutes, and then stained with phalloidin labelled with rhodamine. The comparison between untreated and lead-treated cells revealed that actin redistribution does not regularly occur within neutrophils in lead-containing medium. Immediately after F-MLP stimulation, no focal subcortical localisation of actin was observed. 10 minutes after stimulation, the redistribution of actin was considerably lower in the lead-treated cells than the redistribution which occurred within untreated cells. Moreover, the polarisation of neutrophils supplemented with lead was abortive. Since previous investigations indicated that lead inhibits chemotaxis of neutrophils, these results suggest that one possible cause of this inhibition is related to an effect of lead on actin reorganisation within the cells.
Isolation and Maintenance of Continuous Cultures of Epithelial Cells from Chemically-injured Adult Rabbit Lung
Authors: Houser Sandra , Borges Lolita , Guzowski Dorothy E. , Barile Frank A. 
Published: August 2020

Acute alveolar injury commonly occurs as a result of exposure to a variety of toxic stimuli and is characterised by widespread necrosis of the epithelium, followed by regeneration and hyperplasia of type II alveolar epithelial cells. We studied epithelial proliferation in rabbit lung resulting from a chemical stimulus by isolating the mitotically active cells and establishing them in continuous culture. Acute alveolar injury was induced in rabbits with two daily injections of N-nitroso- N-methylurethane (NNNMU). Four to six days after treatment, the lungs were enzymatically digested and a homogeneous monolayer of epithelial cells was established in culture. The cells displayed a typical cobblestone-like arrangement and cuboidal shape, and represented 95% of the cells isolated. The cultures exhibited contact inhibition and achieved a population doubling level of 11 ± 2. Their epithelial origin was confirmed by positive reactions for immunofluorescent cytokeratin, alkaline phosphatase, and the Papanicolaou stain. Ultrastructurally, the cells showed abundant rough endoplasmic reticulum with dilated cisternae, desmosomes, cytokeratin filaments, and lamellar-like structures early in culture. In addition, the cells accumulated paraquat in a manner similar to that shown by established epithelial cell lines. The results demonstrate that regenerating epithelial cells can be isolated and propagated in culture as a relatively homogeneous population. This system, which is designed to further understanding of the metabolic role of epithelial cells following acute injury, may serve as an in vitro model for pulmonary toxicity studies using a minimal number of animals.
The Fish Pigment Cell: An Alternative Model in Biomedical Research
Authors: Karlsson Jan Olof G. , Grundstrom Nils , Elwing Hans , Andersson Rolf G. G. 
Published: August 2020

Receptor-mediated pigment aggregation within pigment cells (chromatophores) of an isolated fish scale is an ideal model system for functional receptor studies. The superficial layer of the scale contains both dermal chromatophores and postganglionic sympathetic nerves. By means of stimulation of the nerves, or by addition of appropriate receptor agonists, it is possible to elicit pigment aggregation within the chromatophores. A single fish can contribute hundreds of scales, various pharmacological and biochemical experiments are easily carried out and the physiological response, i.e. pigment aggregation, is readily evaluated by the aid of a light microscope or a simple scale photometer. A denervation model, based on isolated scales, permits studies of factors involved in the sensitivity change, which typically takes place after experimental or pathological denervation. By using isolated fish scales it is quite simple to illustrate many biomedically important concepts, like receptor theory and nerve-effector cell communication. This makes the scale a very useful preparation in biomedical education.
Applications of Human Peripheral Blood Lymphocytes in Genotoxicity and Cytotoxicity
Authors: Celotti Lucia , Bianchi Vera 
Published: August 2020

A number of features make peripheral blood lymphocytes an excellent system for studying both genotoxicity and cytotoxicity in humans. They are an abundant and readily accessible source of somatic cells, mostly in a non-proliferative state, but able to be stimulated by mitogens to enter the cell cycle. The blastocyte transformation of lymphocytes is a useful model for investigating the mechanisms which regulate cell-cycle progression in mammalian cells. By stimulating lymphocytes in vitro, it is possible to detect the genetic damages they have sustained in vivo, which become manifest as chromosomal aberrations, sister-chromatid exchanges or gene mutations. The metabolic properties of lymphocytes have been extensively studied, especially with reference to their characteristic collection of enzymes involved in nucleotide turnover, which makes them exquisitely sensitive to changes in intracellular levels of DNA precursors. The data collected on the ability of lymphocytes to metabolise xenobiotics show a marked quantitative difference between resting and proliferating lymphocytes, and minor qualitative differences between lymphocytes and other cell types, e.g. hepatocytes. An indirect approach to detect the metabolism of genotoxic xenobiotics by lymphocytes is the analysis of DNA adducts in their chromatin after in vivo or in vitro exposure. Lymphocytes can be employed to identify the (cyto)genetic consequences of in vivo genotoxic exposure and inter-individual variation in sensitivity to genotoxic agents. The analysis of mutations at the hgprt locus in lymphocytes is a promising approach for the study of somatic-cell mutations in humans and of the possible mechanisms of in vivo selection against mutants. In the field of cytotoxicity, the applications of lymphocytes are, as yet, still few: the main effect measured is the impairment of the proliferative response to mitogens. But lymphocytes can be employed as primary human cells to be treated in vitro with mutagenic or toxic chemicals in standard genotoxicity and cytotoxicity assays, and offer the advantage of avoiding the problems of inter-species extrapolation of results by testing in a human system. Moreover, the (geno)toxic effects detected in lymphocytes after treatments in vitro may give information on the spontaneous or environmentally-determined susceptibility of the individual donors to xenobiotics.
Comparative Cytotoxicity Rankings of Four Aminoglycoside Antibiotics in the Chang, SIRC and LLC-PK1 Cell Lines
Authors: Linseman Daniel A. , Raczniak Timothy J. , Aaron C. Sidney , Bacon James A. 
Published: August 2020

A series of structurally related aminoglycosides — neomycin, gentamicin, amikacin, and streptomycin — were screened for cytotoxicity in three cell lines, Chang (liver), SIRC (corneal epithelial), and LLC-PK1 (kidney). The main objectives of this study were: firstly, to determine whether the proximal tubule origin of the LLC-PK1 cell line conferred increased sensitivity to this class of xenobiotic when compared to cell lines derived from organs other than the kidney; and secondly, to determine whether any of the cell lines would rank the in vitro cytotoxic potential of the compounds in an order consistent with their in vivo toxicities. LDH leakage and cell proliferative effects (CP) were the endpoints used to measure cytotoxicity. The proximal tubule derivation of the LLC-PK1 cell line did not appear to confer significantly increased sensitivity to any of the aminoglycosides tested using LDH release and cell proliferation as endpoints of cytotoxicity. The relative cytotoxicity rankings were as follows: Chang — gentamicin>neomycin>amikacin>streptomycin (LDH), neomycin∼gentamicin∼streptomycin >amikacin (CP); SIRC — neomycin∼gentamicin∼streptomycin>amikacin (LDH and CP); and LLC-PK1 — gentamicin∼streptomycin>neomycin>amikacin (LDH), and streptomycin >neomycin>gentamicin∼amikacin (CP). The results suggest that the Chang line provides a cytotoxicity ranking consistent with in vivo nephrotoxicity data. The SIRC line ranks amikacin the least cytotoxic, but fails to discriminate between the cytotoxicities of gentamicin, neomycin and streptomycin. The LLC-PK1 cell line ranks the compounds in an order which is inconsistent with in vivo results. The LLC-PK1 cell line appears to be the most sensitive to streptomycin, which is the only agent tested that is not accumulated in the kidney in vivo. The results may reflect basal cytotoxicity, since relatively non-specific endpoints were used. Perhaps the LLC-PK1 cell line would rank the cytotoxic potential of this class of compounds more accurately if parameters which are more renal-specific were measured as endpoints.
Progestins and Antiprogestins: A Review of Their Role in Medicine and Bioassays Used in Their Development
Authors: Bigsby Robert M. 
Published: August 2020

The physiological role of ovarian progesterone in reproduction and the medical uses of synthetic progestins and antiprogestins are briefly reviewed. Although a number of progestins are in wide use, the search continues for better analogues that display fewer of the unwanted effects of the present compounds. The one antiprogestin approved for human use to date, RU486, exhibits considerable antiglucocortoid activity The classical bioassays currently in use for the development of these steroid analogues depend upon in vivo progestin effects. However, progestins induce measurable responses in several cell culture systems that could be used as alternative bioassays. Rabbit uterine stromal cells in primary culture are especially suitable for such use. Addition of progesterone to these cultures stimulates synthesis of a 42 kilodalton (42kD) protein that appears in the medium. The 42kD protein response is specific for a progesterone receptor-mediated event and it can be blocked by known progestins. Using this culture system as a bioassay, one rabbit yields enough cells to measure the effect of 30 test doses in triplicate. Thus, a culture system is described that could substitute for current in vivo bioassays. This culture bioassay would allow large scale screening for potential progestin or antiprogestin activity.
An International Reference Chemical Data Bank would Accelerate the Development, Validation and Regulatory Acceptance of Alternative Toxicology Tests
Authors: Purchase Iain F.H. 
Published: August 2020

Toxicologists involved in safety evaluation have a primary responsibility for ensuring that their results are the best possible for predicting human health effects. Currently, the scientific and regulatory consensus is that animal-based studies provide the best possible evidence. Thus, toxicologists are faced with ethical questions about the use of animals for experimental research. In vitro tests which equal or supersede animal studies, in terms of provision of data for human health assessment, are thus a high priority for toxicologists. There is no shortage of ideas for alternative methods and this emphasises the importance of adequate validation. One critical component of validation studies is the selection, evaluation and provision of appropriate chemicals for assessing the performance of alternative tests. Problems are encountered with poor published toxicology data, the difficulty of ensuring the selection of chemicals to represent a sufficiently wide range of chemical classes, disagreement as to the toxicological classification of chemicals and many other issues in the selection and supply of validation chemicals. Validation studies will be much easier to carry out and will be better received by those involved in human hazard assessment if this aspect of the studies is well planned and controlled. It is proposed, therefore, that an international reference collection of chemicals is assembled which is carefully selected for validation of specific toxicological endpoints, carefully reviewed and classified as to toxicity and made available to research workers interested in validating alternative methods. Additionally, the usefulness of the database could be enhanced if the results of validation studies were to be recorded in a central repository.
In Vitro Models for Biochemical Investigations on Programmed Cell Death
Authors: Perotti Mariarosa , Taddei Filippo , Mirabelli Francesca , Bellomo Giorgio 
Published: August 2020

Isolated rat thymocytes treated with methylprednisolone (MPS), cultured human synovial (McCoy's) cells exposed to cold shock and human mammary adenocarcinoma (BT-20) cells treated with Tumour Necrosis Factor (TNF), all showed DNA fragmentation and the morphological and biochemical features of cell death characteristic of a process known as apoptosis. DNA fragmentation in MPS-treated thymocytes and in cold shock-exposed McCoy's cells was preceded by a marked increase in cytosolic free Ca2+ concentration resulting either from a sustained influx of Ca2+ from the extracellular medium or from the release of Ca2+ from intracellular pools. On the other hand, in TNF-treated BT-20 cells, DNA fragmentation was not associated with any early, marked increase in the cytosolic free Ca2+ level. In all three models, however, DNA fragmentation was efficiently prevented by intracellular Ca2+ chelators, calmodulin inhibitors and activators of protein kinase C (PKC). These results suggest that the activation of common mechanisms involving Ca2+ and PKC may be essential for the development of apoptosis.
A Preliminary Investigation into the Opacifying Effects In Vitro of Compounds with Varying Numbers of Nitrogen-containing Groups using Isolated Porcine Corneas
Authors: Igarashi Haruyoshi , Katsuta Yasunaga , Nakazato Yoshiharu , Kawasaki Tohru 
Published: August 2020

Isolated intact porcine corneas were incubated for 4 hours with solutions of various compounds, bathing either the epithelial or endothelial surface or both surfaces, and the resulting opacities were measured. All compounds were tested at 5 x 10-4 M, 5 x 10-3 M, 5 x 10 2M and 1 x 10 1M. Solutions of pilocarpine HC1, carteolol HC1 and timolol maleate (which contain 2 or 4 nitrogens) caused a greater opacity when applied to the endothelial surface than when applied to both the endothelial and epithelial surfaces. By contrast, solutions of sodium lauryl sulphate, befunolol HC1 and dibucaine HC1 (which contain 0, 1 or 3 nitrogens) caused a greater opacity when applied to both surfaces than when applied to the endothelial surface alone. In both groups, there was a good correlation between the greatest opacities and the osmolalities of the various solutions. The difference in responses to the two groups of compounds may be related to the number of nitrogen atoms in the molecules. It is suggested that there is something in the porcine corneal epithelium which inhibits the uptake of compounds containing 2 or 4 nitrogens. Alternatively, in the presence of these compounds, the epithelium may be able to actively pump out water that has entered by diffusion. We wish to thank Mrs A.M. Northover for her linguistic assistance, and the local slaughterhouse at Koriyama-shi for the supply of fresh porcine eyes.
Can the In Vivo Maximum Tolerated Dose be Predicted Using In Vitro Techniques? A Working Hypothesis
Authors: Shrivastava Ravi , John Gareth W. , Rispat Ginette , Chevalier Annick , Massingham Roy 
Published: August 2020

All new chemical entities synthesised in our laboratories have routinely been subjected to in vitro toxicity tests. Out of curiosity, we established a working hypothesis in which the in vitro data could be empirically transformed to predict the in vivo four-week standard maximum tolerated dose (MTD) studies in rats and dogs. As a first step to verifying this hypothesis, we report here the findings of an in vitro cytotoxicity study of 25 compounds randomly selected from our files, possessing a wide range of pharmacological activities and for which data from standard four-week MTD studies were available. Single blind in vitro toxicity studies in three carefully selected types of primary and cell line cultures were carried out. In vitro CT50 (concentration inducing 50% cell death) and CT100 (concentration inducing 100% cell death) values were obtained for each of the three cell types and, using empirical assumptions, these results were used to predict the MTD in vivo in the rat and dog. The actual in vivo threshold and toxic doses were obtained from the MTD study reports. The in vivo toxicity values predicted from the in vitro toxicity results with this series of 25 compounds showed a better than 80% correlation with the actual in vivo results obtained in the MTD studies. Whether or not in vitro cytotoxicity predictions are ultimately found to be directly and consistently related to the MTD in vivo for all pharmacological classes of compounds will require many additional studies, but it is hoped that these results will stimulate the necessary research effort required to answer this question.
Cell Culture Methods to Evaluate the Biocompatibility of Implant Materials
Authors: Ciapetti Gabriela , Cenni Elisabetta , Cavedagna Daniela , Pratelli Loredana , Pizzoferrato Arturo 
Published: August 2020

Cell culture techniques are usually used in the field of biomaterials research and development in order to detect toxic components. Morphological assays are the most widely used methods and give the very first information about the biological compatibility of materials. Cell function assays give more quantitative data, but the comparison of data between different laboratories is difficult. Some of the cell culture methods that are used for biocompatibility studies are described briefly here, and results from our laboratory are reported. Despite some inherent limitations of the cell culture techniques, they are an accurate and reliable method of predicting the biological compatibility of materials to be implanted in vivo.
Application of the EYTEX™ System to the Evaluation of Cosmetic Products and their Ingredients
Authors: Kruszewski Francis H. , Hearn Laura H. , Smith Kyle T. , Teal Janice J. , Gordon Virginia C. , Dickens Michael S. 
Published: August 2020

465 cosmetic product formulations and raw ingredients were evaluated with the EYTEX™ system to determine the potential of this in vitro alternative for identifying eye irritation potential. The EYTEX™ system is a non-animal, biochemical procedure developed by Ropak Laboratories, Irvine, CA, that was designed to approximate the Draize rabbit eye irritation assay for the evaluation of ocular irritation. Avon Products Inc. provided all the test samples, which included over 30 different product types and represented a wide range of eye irritancy. All the EYTEX™ protocols available at the time of this study were used. Samples were evaluated double-blind with both the membrane partition assay (MPA) and the rapid membrane assay (RMA). When appropriate, the standard assay (STD) and the alkaline membrane assay (AMA) were used, as well as specific, documented protocol modifications. EYTEX™ results were correlated with rabbit eye irritation data which was obtained from the historical records of Avon Products Inc. A positive agreement of EYTEX™ results with the in vivo assay was demonstrated by an overall concordance of 80%. The assay error was 20%, of which 18% was due to an overestimation of sample irritancy (false positives) and 2% was attributed to underestimation (false negatives). Overestimation error in this study was due in part to the inability of the protocols to accurately classify test samples with very low irritation potential. Underestimation of sample irritancy was generally associated with ethoxylated materials and high concentrations of specific types of surfactants. 100% sensitivity and 85% predictability were described by the data, indicating the efficiency of EYTEX™ in identifying known irritants. A specificity rate of 39% showed the EYTEX™ assay to be weak in discerning non-irritants. However, the EYTEX™ protocols used in this study were not designed to identify non-irritants. A compatibility rate of 99% proved the effectiveness of the EYTEX™ assay in accommodating a diversity of product types. The EYTEX™ system protocols, when used appropriately, can provide a conservative means of assessing the irritant potential of most cosmetic formulations and their ingredients.
Cytotoxicity of Continuous Ambulatory Peritoneal Dialysis (CAPD) Solutions. A Biocompatibility Study Involving Human Polymorphonuclear Granulocytes Rather than Laboratory Animals
Authors: Schambye Hans T. , Pedersen Fritz B. , Wang Palle 
Published: August 2020

Continuous amulatory peritoneal dialysis (CAPD) is a well-established treatment for renal failure. Peritonitis is the most important and serious complication to CAPD. The predisposition of patients to contract peritonitis has been attributed to functional impairment of immunoactive cells in the peritoneal cavity due to cytotoxicity of the dialysis solutions used. A model for biocompatibility studies of CAPD solutions is presented, in which the migration and phagocytotic capacity of normal isolated human polymorphonuclear granulocytes (PMN) were examined after exposure to the test solutions. The methods proved to be highly reproducible. The commercially-available lactate-based CAPD solutions tested reduced PMN function, mostly due to their low pH. Cell function was improved by elevation of pH, but not to the control level, when the cells were exposed to RPMI — a standard cell culture medium. A new bicarbonate-based CAPD solution proved to be less cytotoxic than the lactate-based ones, and is at present undergoing clinical evaluation.