The purpose of this study was to use confirmatory factor analysis (CFA) to revise the factor structure of the CSAI-2 using one data set, and then to use CFA to validate the revised structure using a second data set. The first data set (calibration sample) consisted of 503 college-age intramural athletes, and the second (validation sample) consisted of 331 intercollegiate (Division I) and interscholastic athletes. The results of the initial CFA on the calibration sample resulted in a poor fit to the data. Using the Lagrange Multiplier Test (Gamma) as a guide, CSAI-2 items that loaded on more than one factor were sequentially deleted. The resulting 17-item revised CSAI-2 was then subjected to a CFA using the validation data sample. The results of this CFA revealed a good fit of the data to the model (CFI = .95, NNFI = .94, RMSEA = .054). It is suggested that the CSAI-2R instead of the CSAI-2 be used by researchers and practitioners for measuring competitive state anxiety in athletes.

Use of the specific-locus test to measure the frequency of transmitted gene mutations induced in mouse spermatogonia has shown ethylnitrosourea to be by far the most potent mutagen yet discovered in the mouse. The dose used, 250 mg/kg, gave a mutation rate 5 times as high as had been obtained with 600 R, the most effective acute dose of x-rays. Compared to procarbazine, heretofore the most mutagenic chemical known in the mouse, ethylnitrosourea proved to be 15 times more mutagenic than the peak effect obtained with the most effective dose of procarbazine. Because of its high mutagenicity, ethylnitrosourea can serve as a model compound in exploring the effect of such factors as dose response, dose fractionation, sex, and cell stage on the mutagenic action of a chemical. Ethylnitrosourea is clearly the mutagen of choice for the production of any kind of desired new gene mutations in the mouse. More than a score of chemicals, most of them well-known mutagens in other organisms, have been tested by the mouse specific-locus method. Only three, however, have shown a clear-cut positive mutagenic effect in treated mouse spermatogonial stages (1), and the most effective dose of the most potent of these three-namely, procarbazine (2)-produced only approximately one-third as many mutations as had been obtained with 600 R (1 R = 2.6 X 10-4 coulombs/kg) of acute x-irradiation. The impression was developing that perhaps the mammalian testis was efficiently protected against damage by chemicals. The possibility also existed that the spermatogonia might be effective at repairing mutational damage. It began to appear possible that perhaps no chemical could break through the mammalian body's defense barriers to produce more than a moderate mutagenic effect in spermatogonia.Although repair and other defense mechanisms may still prove to operate against many substances, the present results show that N-ethyl-N-nitrosourea (ENU) provides a dramatic exception.MATERIALS AND METHODS ENU (purchased from Bio-Clinical Laboratories, Bohemia, NY) was dissolved in phosphate buffer (3) adjusted to pH 6. The dose injected intraperitoneally was matched to the body weight of each animal by adjusting the volume of the injected solution, which never exceeded 1 ml. Wild-type (101XC3H)Fl male mice 9-19 weeks old were injected with a single dose (250 mg/kg) of ENU. All animals given this dose survive, whereas a 300-mg/kg dose kills about 40%. All injections were completed within less than 1 hr after the chemical was dissolved. The injected males were mated to females of our standard specific-locus test strain (T) which is homozygous for seven marker genes (4). Each male was mated to a group of either two or four females and moved to a new group of females each week. After each 7-week period the males were rotated back to the original group of females to start the cycle over again. The offspring were scored for mutations at the seven loci. RESULTS AND DISCUSSIONThe 250-mg/kg dose induced a long period of sterility. The males were fertile for a...

In order to maximize the mutagenic effectiveness of N-ethyl-N-nitrosourea in mouse stem-cell spermatogonia, advantage was taken of the fact that these cells can accumulate mutations from repeated doses given over relatively long time periods. Repeated doses (100 mg/kg) of ethylnitrosourea injected intraperitoneally into male mice at weekly intervals were found to allow adequate survival and fertility with total dosages of 300 and 400 mg/kg. The specificlocus mutation frequencies at these dosages were, respectively, 1.8 and 2.2 times that obtained with the maximal practicable single dose of 250 mg/kg. The mutation frequency induced by a 400 mg/kg dosage of ethylnitrosourea is 12 times the maximal mutation frequency achievable with a single exposure to x-rays and 36 times that reported for procarbazine, the most effective chemical mutagen previously known for mouse stem-cell spermatogonia. Ethylnitrosourea is already the mutagen of choice in deliberate attempts to create mouse models for human disease and in any experiments in which a maximal mutation rate is desired. Repeated-dose regimens similar to the ones reported here should increase the efficiency of such studies.One advantage of determining induced mutation rates in stem-cell spermatogonia is that these cells can accumulate mutational lesions throughout the reproductive life span of the animal; therefore, repeated doses of mutagens can be given over relatively long time periods to amass a total dosage higher than that tolerated in a single exposure. Ethylnitrosourea (EtNU) has been shown to be the most effective mutagen for induction of specific-locus mutations in mouse spermatogonia (1,2). This has led rapidly to its being the mutagen of choice by many investigators (3,4). Therefore, it seemed useful to test whether repeated doses could be given to yield higher specific-locus mutation rates than those obtained by single exposures. This paper presents data from specific-locus tests with repeated doses of EtNU and from survival and fertility tests that were conducted prior to the specific-locus tests in order to choose feasible dosage regimens. A brief abstract of the preliminary results on survival and fertility has appeared (5). MATERIALS AND METHODSSurvival and Fertility Tests. EtNU, synthesized in our laboratory by D. G. Doherty, was dissolved in phosphate buffer (6) adjusted to pH 6. The dose injected intraperitoneally was matched to the body weight of the animals by adjusting the volume of solution injected, which never exceeded 1 ml. Male (101 x C3H)F1 mice were injected with dosages of 300 or 400 mg of EtNU/kg, given in 100 mg/kg doses. In four separate experiments, the individual doses were spaced 1 day, 2 days, 4 days, or 7 days apart, respectively. Six mice, 12 weeks old at the first injection, were in each dosage group in each experiment. All injections were completed within 1 hr after the EtNU was dissolved. Seven weeks after the final injection, these males were mated to females of our standard specific-locus test strain, T, which is h...

The germline supermutagen, N-ethyl-N-nitrosourea (ENU), has a variety of effects on mice. ENU is a toxin and carcinogen as well as a mutagen, and strains differ in their susceptibility to its effects. Therefore, it is necessary to determine an appropriate mutagenic, non-toxic dose of ENU for strains that are to be used in experiments. In order to provide some guidance, we have compiled data from a number of laboratories that have exposed male mice from inbred and non-inbred strains or their F(1) hybrids to ENU. The results show that most F(1) hybrid animals tolerate ENU well, but that inbred strains of mice vary in their longevity and in their ability to recover fertility after treatment with ENU.