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H Spielmann

Publications and source records attributed to H Spielmann.

At least 19 recordsLinked to original sources
PubMed2001

The use of dogs as second species in regulatory testing of pesticides. Part II: Subacute, subchronic and chronic studies in the dog.

Data on 172 pesticides (fungicides, herbicides, insecticides and other pesticides) submitted for regulatory purposes during the past 40 years to the German Federal Institute for the Health Protection of Consumers and Veterinary Medicine (BgVV) were analysed to determine whether chronic studies in dogs (52/104 weeks) provide essential additional specific toxicological compared with subchronic (13 weeks) or subacute (4 weeks) studies in the same species. Comparison of the lowest observed effect levels (LOELs) in dogs revealed no significant differences between subchronic and chronic studies but a significant difference between subacute studies and subchronic or chronic studies. Moreover, there was a significant correlation between the LOELs determined in subchronic studies and those determined in chronic studies in dogs (r = 0.78-0.84). The distribution of target organ toxicity determined in chronic studies in dogs was not significantly different from the distribution determined in subchronic studies, except for effects on the spleen in studies on herbicides which were only observed in chronic studies and in combined subchronic/chronic studies, but never in subchronic studies. Organ-specific effects that were observed in chronic studies but not in subchronic studies were found in 30 of 55 studies on fungicides, in 25 of 44 on herbicides, in 17 of 38 on insecticides and in 10 of 16 on other pesticides. Compared with 26-week studies, additional organ-specific toxic effects were found in three of five, in three of four, in one of three and in one of one 52/104-week studies on fungicides, of herbicides, of insecticides and other pesticides, respectively. The organ-specific effects that were seen only in the chronic dog studies were evaluated according to their severity, e.g. significant damage to organs versus changes in enzyme activities that do not affect organ function or histology. Such effects were not considered to be specific for dogs in chronic studies if similar effects were also found in chronic studies in rodents (rat or mouse). In 15 of 141 studies in dogs serious side effects were observed in chronic studies that were not observed in subchronic studies. Furthermore, for 9 of 172 pesticides significant new effects were seen in 52/104-week studies when compared with 4- or 13-week studies and in 7 of 141 52/104-week studies when compared with 13-week studies. Analysis of the severity of organ-specific toxic effects of pesticides revealed that chronic long-term studies (52/104 weeks) in dogs do not provide specific additional information to 26-week studies in the same species.

Animals↗
PubMed2001

[Report on the ICCVAM workshop on in vitro methods for assessing acute systemic toxicity].

It was suggested in the ICCVAM workshop that the Register of Cytotoxicity (RC), using in vitro cytotoxicity data to predict the in vivo starting doses, should be implemented into acute toxicity testing as soon as possible. The validity of the in vitro cytotoxicity data to establish appropriate starting doses for acute toxicity testing will be assessed experimentally. Secondly, in order to replace the use of animals in acute lethality testing a formal validation will be conducted in which the ability to predict rodent LD50 values and toxicity classes from cytotoxicity data will be evaluated.

Animal Testing Alternatives↗
PubMed2001

[Permanent embryonic mouse germ cell-lines, an in vitro alternative to in vivo germ cell mutagenicity tests].

Germ cell mutagenesis is required by the 7th amendment of the directive 67/548 EEC into the national regulations on existing chemicals. Officially accepted in vivo test systems for stage specific mutagenicity are the dominant lethal (DL) test and the specific locus test (SLT) in mice. An acceptable in vitro alternative designed to address germ cell mutagenesis and discriminate between male and female specific effects is not available at present. In order to offer a sensitive and predictive in vitro method to assess the genotoxic potential of chemical agents on male and female reproduction, we established primordial germ (PG) cell-derived permanent embryonic germ (EG) cell lines of the mouse (strain BALB/cJ). The differences in developmental sensitivity of the EG(3) cell line and differentiated fibroblast cells 3T3 were comparatively tested with cytotoxicity assay (MTT test ) and genotoxic studies (SCE-assay) under identical test conditions. The concentration-response curves reflected the female cell line EG(3) to be extremely sensitive concerning cytotoxic and genotoxic endpoints. Therefore this cell line was used to classify in vivo genotoxic and non-genotoxic test substances with different potential endpoints. Applying linear discriminant analysis three endpoints were identified for the correct classification (100%) of all test chemicals, namely the SCE(200) value (increase of 200% in the mean number of SCEs per metaphase spread) for EG(3) (3 hrs and 24 hrs assay) and the IC(5)0 value for EG(3) after 3 hrs of exposure to test chemicals.

3T3 Cells↗
PubMed2000

Development of prediction models for three in vitro embryotoxicity tests in an ECVAM validation study.

Since 1997 the National Center for Documentation and Evaluation of Alternative Methods to Animal Experiments, ZEBET, in Berlin, has been coordinating a validation study aimed at prevalidation and validation of three in vitro embryotoxicity tests, funded by the European Center for the Validation of Alternative Methods (ECVAM) at the Joint Research Center (JRC, Ispra, Italy). The tests use the cultivation of postimplantation rat whole embryos (WEC test), cultures of primary limb bud cells of rat embryos (micromass or, MM, test), and cultures of a pluripotent mouse embryonic stem cell line (embryonic stem cell test or EST). Each of the tests was performed in four laboratories under blind conditions. In the preliminary phase of the validation study 6 out of 20 test chemicals comprising different embryotoxic potential (non, weakly, and strongly embryotoxic) were tested. The results were used to define biostatistically based prediction models (PMs) to identify the embryotoxic potential of test chemicals for the WEC test and the MM test. The PMs developed with the results of the preliminary phase of the validation study (training set) will be evaluated with the results of the remaining 14 test chemicals (definitive phase) by the end of the study. In addition, the existing, improved PM (iPM) for the EST, which had been defined previously, was evaluated using the results of the preliminary phase of this study. Applying the iPM of the EST to the results of this study, in 79% of the experiments, chemicals were classified correctly according to the embryotoxic potential defined by in vivo testing. For the MM and the WEC test, the PMs developed during the preliminary phase of this validation study provided 81% (MM test) and 72% (WEC test) correct classifications. Because the PM of the WEC test took into account only parameters of growth and development, but not cytotoxicity data, a second PM (PM2) was developed for the WEC test by incorporating cytotoxicity data of the differentiated mouse fibroblast cell line 3T3, which was derived from the EST. This approach, which has previously never been used, resulted in an increase to 84% correct classifications in the WEC test.

3T3 Cells↗
PubMed2000

[Prediction of human lethal concentrations by cytotoxicity data from 50 MEIC chemicals].

Procedures for predicting human toxicity on the basis of cytotoxicity data for different chemicals are of current interest. The study was designed to clarify the possibility of predicting human toxicity by using the cytotoxicity values IC(50x) of the 50 MEIC chemicals listed in the Registry of Cytotoxicity (RC). All calculations with the data of cytotoxicity and in vivo toxicity were carried out uniformly by using standardised methods with the aim of comparing the results in the literature with each other. The following results were achieved: Firstly, the IC(50x) values in the RC are suited better for predicting human toxicity than IC(50) values determined in cell culture experiments with one cell type and one cytotoxic endpoint. This result is correct for the values of linear regression parameters as well as for the values of the prediction error (PE) defined by Ponsoda et al. (1997). Secondly, by using the geometrical mean of four lethal concentrations (LCx) - calculated from the tabulated lethal concentration (LC), lethal plasma concentration (LPC), clinical lethal concentration (CLC) and forensic lethal concentration (FLC) - the parameters for predicting the human toxicity were slightly improved. Moreover, these comparative examinations demonstrate that in all cases the cytotoxicity data are suited better for predicting acute animal toxicity than for predicting acute human toxicity. The results confirm, once more, the reliability and general validity of RC cytotoxicity data for examinations of different problems in cytotoxicology.

Animals↗
PubMed2000

[The ZEBET database on alternative methods to animal experiments in the Internet--a concrete contribution to the protection of animals].

Up from February of the year 2000 ZEBET (German Centre for the Documentation and Validation of Alternative Methods) at the Federal Institute for Consumer Health Protection and Veterinary Medicine (BgVV) put the ZEBET-database on alternative methods to animal experiments on the Internet in English via DIMDI, the German Institute for Medical Documentation and Information (http://gripsdb.dimdi.de/engl/guieng.html). The access is free, moreover DIMDI's complete service is available to visitors of the ZEBET-database. The ZEBET database contains documents on alternatives to testing in animals, which have been carefully evaluated by ZEBET's staff according to the "3Rs"-concept established by Russel and Burch in 1959. Therefore, methods documented in the ZEBET database must meet at least one of the following criteria: "replacement" of an animal experiment by a non-animal method, "reduction" of the number of animals used, "refinement" of an experiment by minimising pain and suffering of animals. In addition, the ZEBET-database provides information on the current stage of development and validation of a method and on the acceptance for either scientific or regulatory purposes. Each document is characterised by the following criteria: the title of a method, keywords, assessment, summary and bibliographic references. To search DIMDI<<s-database and host-system the grips software has to be used. Examples are given for searching in the ZEBET-database. Currently 125 alternative methods are meeting the criteria of the ZEBET database. 50 of them are available online on the internet via DIMDI, the remaining 75 documents will be available by the end of the year 2000. International fellow organisations, e.g. FRAME (Fund for the Replacement of Animals in Medical Experiments) in the UK and CAAT (Johns Hopkins Center for Alternatives to Animal Testing) in the USA, have established links on their web sites to provide visitors free access to the ZEBET-database.

Animal Testing Alternatives↗
PubMed1999

Embryotoxicity screening using embryonic stem cells in vitro: correlation to in vivo teratogenicity.

Blastocyst-derived pluripotent embryonic stem (ES) cells of the mouse can be induced to differentiate in culture into a variety of cell types, including cardiac muscle cells. The embryonic stem cell test that makes use of the differentiation of ES cells into cardiomyocytes in a standardized in vitro model was developed to offer an alternative method to comprehensive in vivo studies in reproductive toxicology about toxic effects of chemicals. ES cells of the mouse cell line D3 are investigated for their preserved capability to differentiate following drug exposure, and both ES cells and differentiated fibroblast cells of the mouse cell line 3T3 are comparatively analyzed for effects on viability. The following endpoints are used to classify the embryotoxic potential of chemicals into three classes of in vitro embryotoxicity (non-, weakly or strongly embryotoxic). These endpoints are: (1) the inhibition of differentiation of ES cells into cardiomyocytes after 10 days of treatment, and the decrease of viability (cytotoxicity) of (2) 3T3 cells and (3) ES cells after 10 days of treatment, determined by a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) test. 50% inhibition concentrations for differentiation (ID(50)) and cytotoxicity (IC(50)D3 and IC(50)3T3) are calculated from concentration-response curves. Applying linear analysis of discriminance, a biostatistical prediction model (PM) was developed. This procedure identified three variables, the lg(IC(50)D3), the lg(IC(50)3T3) and the relative distance between IC(50)3T3 and ID(50), that improved the separation of the three classes of embryotoxicity compared to the prediction model that was originally proposed after test development. Unlike the original PM, the improved PM incorporates as one variable the relative distance between IC(50)3T3 and ID(50), instead of the ratio ID(50)/IC(50)D3 that was used previously.

Animals↗
PubMed1999

[Development of prediction models for three in vitro embryotoxicity tests which are evaluated in an ECVAM validation study]

In 1997 ZEBET started the co-ordination of a study funded by the European Centre for the Validation of Alternative Methods (ECVAM) with the aim of pre-validation and validation of three in vitro embryotoxicity tests. These tests employ the cultivation of post-implantation whole rat embryos (WEC test), cultures of primary limb bud cells of rat embryos (micromass test, MM-Test), and cultures of a pluripotent mouse embryonic stem cell line (embryonic stem cell test, EST). In the current Validation Study each of the tests is evaluated in four laboratories under blind conditions. In an initial phase of the validation study six out of 20 test chemicals comprising different embryotoxic potential (non, weak and strong embryotoxic) were tested. The results were used to improve the prediction models (PM) for the WEC test and the MM-Test in order to identify the embryotoxic potential of test chemicals. In addition, the existing PM for the EST was evaluated using the results from testing of the initial six chemicals. The PM for the EST was developed using the results of a previous pre-validation study (Scholz et al.,1999), in which 94% of the learning sample were classified correctly. Applying this PM to the results of the initial phase of the current validation study, 80% of the experiments were classified correctly according to the embryotoxic potential of the tested chemicals in vivo. Applying the PM for the MM-Test and the WEC test that were developed during the current validation study in both tests, 79% correct classifications were achieved. Since the PM of the WEC-Test took into account only parameters of growth and development, but not cytotoxicity data, a second PM (PM2) for the WEC was developed that was improved by incorporating cytotoxicity data of the differentiated mouse fibroblast cell line 3T3 derived from the EST. This approach, which has previously never been used as an adjunct to the WEC test, resulted in an increase of correct classifications to 96%.

Journal Article↗
PubMed1998

The use of dogs as second species in regulatory testing of pesticides. I. Interspecies comparison.

The relevance of studies in dogs on regulatory testing of pesticides was examined retrospectively using data of 216 pesticides (acaricides, fungicides, growth regulators and hormones, herbicides, insecticides, molluscicides, nematicides, rodenticides, synergists for insecticides) submitted for regulatory purposes during the past 40 years to the Federal Institute of Health Protection of Consumers and Veterinary Medicine (BgVV), the competent national authority in Germany. At first the relevance of the no-observed-effect levels (NOEL) for safety assessment was evaluated for each chemical in 4-week (subacute), 13-week (subchronic) and 52/104-week (chronic) toxicity studies carried out on dogs, rats and mice. After subchronic and chronic application of fungicides the sensitivity of rats and dogs to the toxic chemicals was quite similar. However, the dog was generally a more sensitive species to toxic effects of insecticides than rat and mouse. On the other hand the NOEL was lower in the rat than the dog in chronic studies on herbicides. When the lowest-observed-effect level (LOEL) was evaluated in animal species, the dog was the most sensitive in approximately 15% of the studies. Mice were found to be the most sensitive species only in approximately 1% of the studies on 216 pesticides. Comparison of organ specific toxicity at the LOEL in subacute studies on fungicides and herbicides revealed a poor correlation of target-specific organ toxicity across species. However, in the subchronic and chronic studies (13 and 52/104 weeks) no significant differences in species-specific organ toxicity were observed in the three species rat, mouse and dog. The only exception were haematoxic effects in chronic studies on herbicides, which were more frequent in dogs (40%) than in rats and mice (20%). The results support the established concept that studies on dogs and rats are important for the safety assessment of pesticides, while studies on mice do not provide further information, except for detection of an oncogenic potential which is a further controversial issue. Further analysis of subacute, subchronic and chronic studies in dogs should reveal if all of the studies are essential for safety assessment of pesticides.

Animals↗
PubMed1998

13th Meeting of the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC): alternative testing methodologies for organ toxicity.

In the past decade in vitro tests have been developed that represent a range of anatomic structure from perfused whole organs to subcellular fractions. To assess the use of in vitro tests for toxicity testing, we describe and evaluate the current status of organotypic cultures for the major target organs of toxic agents. This includes liver, kidney, neural tissue, the hematopoietic system, the immune system, reproductive organs, and the endocrine system. The second part of this report reviews the application of in vitro culture systems to organ specific toxicity and evaluates the application of these systems both in industry for safety assessment and in government for regulatory purposes. Members of the working group (WG) felt that access to high-quality human material is essential for better use of in vitro organ and tissue cultures in the risk assessment process. Therefore, research should focus on improving culture techniques that will allow better preservation of human material. The WG felt that it is also important to develop and make available relevant reference compounds for toxicity assessment in each organ system, to organize and make available via the Internet complete in vivo toxicity data, including human data, containing dose, end points, and toxicokinetics. The WG also recommended that research should be supported to identify and to validate biological end points for target organ toxicity to be used in alternative toxicity testing strategies.

Animal Testing Alternatives↗
PubMed1998

Reproduction and development.

The currently developed and validated in vitro tests for female and male fertility and also for developmental toxicity are described and evaluated according to their potential use as screening or replacement alternatives to the established in vivo tests in reproductive and developmental toxicology. Alternative methods today can only be used to evaluate a few specific components of the integrated reproductive functions in both females and males. However, in the field of developmental toxicity testing there is a strong theoretical and empirical basis for the predictive power of in vitro screens using mammalian embryos as well as embryonic cells and tissues. Several of these assays have been validated or are currently undergoing validation in several laboratories and are > 80% concordant with in vivo results. Failure to achieve 100% accuracy reflects the inherent limitations of these systems, which are manageable, as the concordance rates are still good. The level of concordance suggests that these assays are adequate for screening purposes to complement traditional in vivo testing. The use of these assays as screens will save valuable in vivo testing resources for those compounds most likely to enter the market and to which people will be exposed.

Animal Testing Alternatives↗
PubMed1997

IRAG working group 2. CAM-based assays. Interagency Regulatory Alternatives Group.

CAM-based assays, in which test material is applied to the chorion allantoic membrane (CAM) of embryonated chicken eggs, were assessed as alternatives to the Draize eye irritation test. Two general types of CAM-based assays are currently in use, the HET-CAM test and the CAMVA assay. Evaluations were made of five data sets produced with three different modifications of the HET-CAM test and two data sets obtained with the same CAMVA protocol. Data sets consisted of 9-133 test chemicals, usually from the sponsor's product line, and also from a validation trial. Each data set and assay protocol were analysed for quality of data, purpose and proposed use of the assay, range of responses covered, range of test materials amenable, current use in safety and risk assessment both in-house and for regulatory purposes. Since the MMAS Draize score was not available for all in vivo data sets, the sigma MMMIS, which correlates well with the MMAS, was used instead. In vitro/in vivo correlations calculated with Pearson's linear coefficient ranged from r = 0.6 to r = 0.9 for six of seven data sets. Corneal opacity and inflammation of the iris showed the best correlation to in vitro data. Prediction rates were significantly improved when partial linear regression was used, and the predictivity of three different HET-CAM protocols was almost the same. HET-CAM assays showed the best prediction with surfactants and surfactant-based formulations, whereas the CAMVA assay provided the best performance with alcohols.

Allantois↗
PubMed1997

Evaluation of eye irritation potential: statistical analysis and tier testing strategies.

Eye irritation testing, specifically the Draize test, has been the centre of controversy for many reasons. Several alternatives, based on the principles of reduction, refinement and replacement, have been proposed and are being used by the industry and government authorities. However, no universally applicable, validated non-animal alternative(s) is currently available. This report presents a statistical analysis and two testing approaches: the partial least squares multivariate statistical analysis of de Silva and colleagues from France, the tier-testing approach for regulatory purposes described by Gerner and colleagues from Germany, and the three-step tier-testing approach of the US Interagency Regulatory Alternatives Group described by Gupta and Hill. These approaches were presented as three separate papers at the November 1993 Interagency Regulatory Alternatives Group (IRAG) Workshop on Eye Irritation Testing; they have been summarized and combined into the following three-part report. The first part (de Silva et al.) presents statistical techniques for establishing test batteries of in vitro alternatives to the eye irritation test. The second (Gerner et al.) and third (Gupta and Hill) parts are similar in that they stage assessment of information by using a combination of screening information and animal testing to effect reductions in animal use and distress.

Animal Testing Alternatives↗
PubMed1997

Drug use in Nepal: the view from the street.

This study uses qualitative research techniques to examine heroin use in Nepal. It explores the life histories of 16 heroin users in Kathmandu, the country's capital, emphasizing those who are street children or who are otherwise displaced. The cases document that the initiation of use in Nepal is a complex process which includes: certain personality traits; an early history of culturally acceptable use of alcohol, tobacco, marijuana, or hashish; peer influence; and the specific social setting of users. Outside (i.e., foreign) influences are included in the mix, but never as a single determinant of drug use. Factors specific to the Nepali scene include the traditional association of forms of marijuana with certain religious contexts and the availability of heroin. An additional factor is the poverty of the urban setting. The approach in Nepal to dealing with drugs primarily involves a realization of the role played by the interaction between personality and social setting in the fullest meaning of that term.

Adolescent↗