Multi-Sample Slippage Test for Ordered Observations

A multi-sample slippage test based on ordered observations has been given. The test statistic is based on the sum of ranks of the sample. The probability distribution of the test statistic has been worked out for small sample and it turns out to be chi-square distribution for large sample. The analytical procedure has been explained by a numerical example.     

Rank Analysis of Block Designs Having Different Cell Frequencies

A distribution–free test is considered for testing the treatment effects in block designs with different cell frequencies. A test statistic which is a function of treatment ranks has been proposed which is distributed as chi-square for large samples. The null distribution of the test statistic has been obtained. The entire procedure has been explained by a numerical example.     

Effectiveness of a battery of tests to assess the potential mutagenic danger of chemical compounds

A new method for assessing the efficiency of batteries of arbitrary numbers of tests is proposed. The posterior probability of the mutagenicity of the substances studied has been estimated using discriminant analysis. The results of tests in each test system has been presented as the probability to obtain a positive result in the given test system. This has made it possible to decrease the sample size as the number of tests in the battery increased. As a result, prognostic power may be assessed even if the matrix of results is incomplete. This approach has been used to estimate the weights of evidence for mutagenic activities of 105 chemical compounds studied by means of a battery of four tests: Ames's test, the test for chromosome aberrations in vitro, the test for cytogenetic defects in vivo, and the test for dominant lethal mutations in rodents.     

Efficiency of Batteries of Tests for Estimating Potential Mutagenicity of Chemicals

A new method for assessing the efficiency of batteries of arbitrary numbers of tests is proposed. The posterior probability of the mutagenicity of the substances studied has been estimated using discriminant analysis. The results of tests in each test system has been presented as the probability to obtain a positive result in the given test system. This has made it possible to decrease the sample size as the number of tests in the battery increased. As a result, prognostic power may be assessed even if the matrix of results is incomplete. This approach has been used to estimate the weights of evidence for mutagenic activities of 105 chemical compounds studied by means of a battery of four tests: Ames's test, the test for chromosome aberrations in vitro, the test for cytogenetic defects in vivo, and the test for dominant lethal mutations in rodents.     

Efficiency of the prediction of carcinogenic activities of chemical substances based on scoring somatic mutations in the soybean Glycine max (L.) Merrill

The efficiency of scoring somatic mutations in soybean (Glycine max (L.) Merrill) leaves as a test for carcinogenic activity of chemical substances in rodents has been evaluated. The efficiency of the test used alone or as part of a battery of tests has been estimated. The mutagenic activities of some chemical substances estimated using the soybean test are presented. Selective information on the carcinogenic activities of substances obtained in special carcinogenicity tests has been used as a quantitative measure of the efficiency of the tests with soybean leaves. To estimate the weight of evidence for the presence of this activity in the tested substances, a special function has been used whose values are uniquely related to the complete information, which is the sum of a priori information and the information obtained after testing. In general, the results have shown that the somatic mutation score test using soybean leaves is at least as efficient as the well-known tests that are generally used now, such as the Ames test and the chromosome aberration score test using mammalian cells in vitro. This test may be promising for the formation of efficient short-term test batteries.     

Applications of the Poly-K Statistical Test to Life-Time Cancer Bioassay Studies

The statistical analysis of cancer bioassay data has historically depended on the pathological determination of the experimental animal's cause of death. The poly-k statistical test has provided a method of statistical analysis of animal bioassay data without the need for cause of death information. The test has been shown to have good statistical properties in the typical 2-year cancer bioassay. However, while the poly-k test has been applied to chronic lifetime animal studies, it has not been formally evaluated with respect to the operating characteristics of this statistical test when applied to such studies. Thus, our objective is to assess the performance of the poly-k test for lifetime studies and to make comparisons with other tests. We observed in one recent lifetime study of the gasoline additive methyl tertiary butyl ether (MTBE) that the application of the poly-k test was not statistically robust. Simulation studies were subsequently conducted for a limited number of scenarios of lifetime cancer bioassays. These simulations showed that the poly-k test is not statistically robust for testing effect of increasing dose in some lifetime cancer studies.     

Efficiency of the prediction of carcinogenic activities of chemical substances based on scoring somatic mutations in the soybean <Emphasis Type="Italic">Glycine max</Emphasis> (L.) Merrill

The efficiency of scoring somatic mutations in soybean (Glycine max (L.) Merrill) leaves as a test for carcinogenic activity of chemical substances in rodents has been evaluated. The efficiency of the test used alone or as part of a battery of tests has been estimated. The mutagenic activities of some chemical substances estimated using the soybean test are presented. Selective information on the carcinogenic activities of substances obtained in special carcinogenicity tests has been used as a quantitative measure of the efficiency of the tests with soybean leaves. To estimate the weight of evidence for the presence of this activity in the tested substances, a special function has been used whose values are uniquely related to the complete information, which is the sum of a priori information and the information obtained after testing. In general, the results have shown that the somatic mutation score test using soybean leaves is at least as efficient as the well-known tests that are generally used now, such as the Ames test and the chromosome aberration score test using mammalian cells in vitro. This test may be promising for the formation of efficient short-term test batteries.     

Antibody dynamics of carnivorous mammals and corvine birds infected with Francisella tularensis

The time course of antibody formation in carnivorous mammals and corvine birds infected with a single injection of F. tularensis has been experimentally studied in the agglutination test and the passive hemagglutination test. In carnivorous mammals the allergic transformation of the body has been established by means of the leukocytolysis test.     

Quality control test for immunoreactivity of radiolabeled antibody

A rapid method for the measurement of the immunoreactive fraction of a radiolabeled monoclonal antibody or antibody fragment has been developed. This may be used as a quality control test prior to patient administration of the radiolabeled antibody preparation. The test employs solid phase antigens and the assay is conducted under conditions of antigen excess. Assay parameters have been evaluated and a standardized procedure has been developed. The assay has been compared to a standard extrapolation method and found to give approximately the same result. The test has been used on four different radiolabeled antibodies currently in clinical trials in patients with colorectal cancer. Mean immunoreactive fractions for these radiolabeled antibodies ranged from 35 to 65% and the variability of the immunoreactive fraction ranged from 140 to 240% for different antibodies. We conclude that the quality, defined as the immunoreactive fraction, of radiolabeled antibodies is both low and highly variable, indicating the need for a quality control test of these radiopharmaceuticals in the clinic prior to patient administration.     

Use of the specific rosette formation test in tick-borne encephalitis for the purpose of laboratory diagnosis

In the study of blood samples collected from patients with tick-borne encephalitis, the modified antigen-specific rosette formation test with erythrocytes, loaded with tick-borne encephalitis virus antigen via the specific immunoglobulin, has been used. The number of rosette-forming cells has been the highest during the acute period of the disease. The use of this test has confirmed the clinical diagnosis of the disease, together with hemagglutination inhibition serving as the main diagnostic test, in 35% of cases. The results of this study make it possible to recommend the antigen-specific rosette formation test for the early diagnosis of tick-borne encephalitis.     

The use of image analysis to monitor the germination of seeds of broccoli (Brassica oleracea) and radish (Raphanus sativus)

To study broccoli and radish seed germination under different temperature regimes the germination test has been used to assess final germination percentage, start and rate. This method has been integrated with a computer‐aided image analysis test which is more accurate in monitoring the extent of imbibition phases through the assessment of seed area increase and timing of radicle emergence detected on single seeds. In addition, seed area increase has been used also to establish a close relationship with radicle elongation rate in the time range when ‘visible germination’ is scored by a classical germination test. The results suggest that this image analysis parameter may be considered as a reliable seed imbibition marker to integrate the germination parameters obtained by a germination test.     

Fractionation in Triad Comparisons

A statistical procedure for comparing the performance of a new product with the existing products on the basis of sensory characters has been developed. A test statistic was evolved for testing the null hypothesis of equality of treatment effects in the case of fractional triad comparisons. The null distribution of the test statistic has been obtained and it is found that it has a χ²-distribution for large number of observations. The procedure is quite simple and is based on a distribution-free test requiring only ordinal scale measurement. The method of analysis has been explained by a numerical example.     

Selection of Judges for Sensory Evaluation

A test based on ordered observations for selection of consistent judges for sensory evaluation has been given. The test–statistic depends on the sum of ranks of different products under consideration. The probability distribution of the test-statistic has been worked out for small sample and it turns out to be chi-square distribution for large sample. The analytical procedure has been explained by a numerical example of a taste-testing experiment.     

Methods for detecting interactions between imprinted genes and environmental exposures using birth cohort designs with mother-offspring pairs

Genomic imprinting is a form of epigenetic regulation in mammals in which the same allele of a gene is expressed differently depending on the parental origin of the allele. Traditionally, the detection of imprinted genes that affect complex diseases has been focused on linkage designs with pedigrees or case-parent designs with case-parent trios. In the past two decades, the birth cohort design with mother-offspring pairs has been applied to understand better the effect of environmental influences during pregnancy and beginning of life on the growth and development of children. No work has been done on the detection of imprinted genes using birth cohort designs. Moreover, although the importance of imprinting has been well recognized, no study has looked at how environmental exposures modify the effects of imprinted genes. In this study, we show that the proposed imprinting test using the birth cohort design with mother-offspring pairs is an efficient test for testing the interactions between imprinted genes and environmental exposures. Through extensive simulation studies and a real data application, the proposed imprinting test has demonstrated much improved power in detecting gene-environment interactions than that of a test assuming the Mendelian dominant model when the true underlying genetic model is imprinting.     

Use of the indirect immunofluorescence test in the diagnosis of an infection, caused by Mycoplasma pneumoniae

The indirect immunofluorescence test has been used for the serodiagnosis of M. pneumoniae infections in two paired blood sera of patients with acute respiratory diseases and acute pneumonia. The optimum methods for obtaining M. pneumonia antigen, its fixation and storage have been determined. The data on the study of the sensitivity, specificity and diagnostic value of the test are presented. The indirect immunofluorescence test has been shown to be capable of the simultaneous detection of complete (complement-binding) and incomplete (not binding the complement) antibodies to M. pneumoniae. This test may be used in the diagnostic practice as a highly sensitive, specific and sufficiently simple serological method.     

Determination of tularemia antibodies by an immunoenzyme method on a solid-phase carrier (ELISA)

ELISA "sandwich" techniques have been developed and the optimum assay conditions for detecting specific antibodies in human serum samples have been determined. The possibility of using these techniques for the determination of the level of antibodies to tularemia antigens in the sera of persons immunized with live tularemia vaccine has been shown. Statistically significant differences in the level of antibodies to tularemia antigen in the sera of immunized and nonimmunized persons have been established. The comparative study of five serological methods - ELISA, the agglutination test, the passive hemagglutination test, the immunofluorescence test and the defined antigen substrate sera ( DASS ) techniques - has revealed the advantage of ELISA, whose sensitivity has proved to be considerably higher than that of all other methods used in our work.     

Stratified Fisher's exact test and its sample size calculation

Chi‐squared test has been a popular approach to the analysis of a 2 × 2 table when the sample sizes for the four cells are large. When the large sample assumption does not hold, however, we need an exact testing method such as Fisher's test. When the study population is heterogeneous, we often partition the subjects into multiple strata, so that each stratum consists of homogeneous subjects and hence the stratified analysis has an improved testing power. While Mantel–Haenszel test has been widely used as an extension of the chi‐squared test to test on stratified 2 × 2 tables with a large‐sample approximation, we have been lacking an extension of Fisher's test for stratified exact testing. In this paper, we discuss an exact testing method for stratified 2 × 2 tables that is simplified to the standard Fisher's test in single 2 × 2 table cases, and propose its sample size calculation method that can be useful for designing a study with rare cell frequencies.     

Inventing a new diagnostic test for vaginal infection.

Bacterial vaginosis, which is underdiagnosed in clinical practice, has a characteristic fishy smell because of production of diamines. This smell is the basis of a visual rapid diagnostic test that is technically simple to perform. The test has been patented in Europe and America, and a licence agreement has been negotiated. This paper describes the process from idea to invention to patenting and licensing. The combined costs of research and patenting were met by a multinational company in return for rights to exploit the patent invention. The process has taken nine years and has needed clinical, scientific, legal, and commercial input to get the test to the marketplace.     

A study of the auxins in cabbage using countercurrent distribution

The counter-current distribution technique has been applied to the study of the identity of the auxins present in fresh cabbage. The results indicate that the major fraction of the auxin activity is probably due to 3-indoleacetic acid, but this is not established conclusively. In addition to the material presumed to be 3-indoleacetic acid, two other biologically active fractions were obtained from cabbage. Whether these are other auxins or “precursors” of 3-indoleacetic acid has not been established. It has been demonstrated that the colorimetric test which has been used by other workers is not specific for 3-indoleacetic acid, and conclusions which have been based on the use of this test must be reconsidered.     

Immunoenzyme method in the diagnosis of human brucellosis

The optimum conditions for the determination of specific antibodies in the sera of brucellosis patients by means of enzyme immunoassay (EIA) have been selected. The comparative study of the specificity and sensitivity of EIA and other serological tests has demonstrated that EIA has high diagnostic effectiveness in the diagnosis of acute and chronic brucellosis. The presence of direct correlation between the results of EIA and Coombs' test is observed, which is indicative of the capacity of EIA for detecting both complete and incomplete specific antibodies. It should be pointed out that in all cases the titer of specific antibodies in EIA has been found to be 5-16 times higher than in Coombs' test, the passive hemagglutination test, and agglutination test.