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Notes: Abstract The23Na NMR first order quadrupolar satellite lines are detected and studied in AgNa(NO2)2 single crystals near the paraelectric-ferroelectric phase transition. Although the intensities of the satellites are small the components of the electric field gradient tensor (EFG) at the23Na sites could be deduced from the angular dependence of the first order quadrupolar line splitting with respect to rotations around the three crystallographic axes by applying the Volkoff method. In the paraelectric phase the principal axes system of the EFG coincides with the crystallographic axes system whereas in the ferroelectric phase there is a strongly temperature dependent small non diagonal elementφ xz (T). The EFG principal componentsφ xx andφ yy are strongly influenced whereas the EFG principal componentφ zz is nearly not affected by the ferroelectric phase transition. The observed temperature dependences of the EFG components are related to the temperature variation of the normalized spontaneous polarizationS(T) by assuming a coupling term which is quadratic inS(T). Finally the problem of the intensities of the satellite lines is discussed.

Notes: Abstract Pulse and wide line NMR spectroscopy were applied to small ferroelectric NaNO2 particles, produced from aqueous solution and embedded loosely in silicagel. Mean particle diameters as determined by SEM and TEM were between 0.2 and 5.0 µm. From the cw-experiments it followed, that the particles had the crystalline structure of the bulk. It is shown that the spectrum of critical fluctuations and the phase transition temperature in the particles proved to be independent of the size. If there is a “dead layer” at the particle surfaces its thickness does not exceed 1×10−2µm.

Notes: Summary Meiotic chromosomes of spermatocytes from INH-treated male mice and Chinese hamsters were analysed for chromosome aberrations in diakinesis-metaphase I and metaphase II. The experiments were performed in two laboratories while a third laboratory participated in the chromosome evaluation. No enhancement of chromosome aberrations could be observed after acute treatment of early primary spermatocytes or chronic treatment of spermatogonia with INH.

Notes: Summary Nucleus anomaly test in Chinese hamsters and in rats treated with isoniazid (INH) was carried out according to a standard protocol in two different laboratories. These comprised both short-term studies, in which the tests were performed on animals killed 6, 12, 24, 36, or 48 h after the second of two consecutive doses of 5, 25, or 125 mg/kg INH given at an interval of 24 h, and long-term studies in animals treated with 25 mg/kg INH thrice weekly for 12 weeks. As a rule, each group consisted of at least four animals, and 1000 cells from each animal were examined. In one of the laboratories, a slight, but statistically significant increase in the incidence of nuclear anomalies was observed in two experiments on animals sacrificed 24 h after treatment; in the majority of cases, however, the investigations yielded negative results. Two out of three long-term studies revealed a slight, but statistically significant increase in the incidence of nuclear anomalies.

Notes: Summary Cytogenetic investigations in bone marrow from animals treated with isoniazid (INH) were performed in seven different laboratories according to a standard protocol. The experiments were carried out in the Chinese hamster, the mouse, and the rat. In short-term studies INH was administered twice at an interval of 24 h in doses of 5, 25, and 125 mg/kg, and the animals were sacrificed 6, 12, 24, and 48 h after the second dose. In long-term studies doses of 25 and 125 mg/kg were administered thrice weekly for 12 weeks. As a rule, each group consisted of at least four animals, and 100 metaphases per animal were counted. Statistical analysis of the data showed that the incidence of chromosomal aberrations including gaps lay in the critical range for two groups in one laboratory and was significantly higher than in the control in three groups in another of the seven laboratories. From the results of both the short-term and the long-term studies in all laboratories, however, it may be concluded, that isoniazid does not induce gross chromosomal aberrations.

Notes: Summary Acute and chronic treatment of Chinese hamsters and mice with 5, 25 and 125 mg/kg isoniazid (INH) given by oral intubation did not enhance the chromosomal aberration frequencies in spermatogonia. The structural and numerical aberration rates remained in the range of spontaneous events even after the chronic treatment over 12 weeks with 3×125 mg/kg INH per week. This dose is much higher than normally used for prevention and therapy in man (3–16 mg/kg).

Notes: Abstract The members of the work group “Dominant Lethal Mutations of the ad hoc Committee Chemogenetics” jointly carried out experimental studies in the period from November 1972 until February 1976. On the basis of the results obtained and the experience gained, they worked out on February 27, 1976, a standard protocol for the dominant lethal test (DLT) on male mice. The recommendations are: 1. The mating period should preferentially be as short as possible to obtain information about germ cell-stage specific actions of chemical mutagens. Its selection should be based on the objectives of individual investigators. For screening purposes, and with respect to a high fertilization rate, a 4-day mating period is recommended. 2. The total test period should cover at least 12 mating periods, i.e. the whole spermatogenic cycle. A limitation of the DLT to certain “critical” mating periods of high sensitivity is only permissible in repeat tests, or if the parts of gametogenesis concerned, e.g. spermatogoniogenesis or spermatocytogenesis, are studied by cytogenetical tests. 3. The mode of mating should preferentially be 1∶1. 4. The number of test animals to be used depends on various biological and statistical factors; no generally valid statement can be made concerning the number of test animals. By rule of thumb in the order of 50 fertilized females per group per mating interval is recommended. 5. The individual dosing of the substance in terms of mg/kg body weight is to be preferred. Otherwise, the weights of the animals should not deviate more than 5% from the mean value. 6. Results obtained from ill animals or those that died in the course of the trial should not be included in the evaluation. 7. The sensitivity of the mouse strain used against a standard dose of a known mutagen should be regularly checked; this evidence should be presented in publications. 8. For the following test conditions each investigator should make an optimal choice: animal strain, animal age and housing conditions. The investigator has also to decide whether a preliminary mating, in order to check the fertility of the animals to be used, and vaginal-plug evidence are useful in a given case. 9. The autopsy of the dams is best carried out a fortnight from the middle of the mating interval. 10. The results should be documented as completely as possible in the investigational report. The following data were also considered as essential, serving a direct comparison of the test groups: number of mated females (absolute), number of females with implantation (absolute and in %), number of implantations and of live and dead implants (absolute and per female). If the corpora lutea graviditates were counted, their number as well as the pre-implantation loss (absolute and per female) are to be stated. These data are also desirable for publications. 11. For the biological evaluation the following formula can be used for the calculation of dominant lethal factors: FL% = [1-live implants per female of the test group/live implants per female of the control group]×100 12. Statistical evaluation is an essential part of the DLT and various methods are known. For the statistical evaluation it is decisive which biological model and which statistical criteria are most important for the investigator. The DLT must be carried out according to the requirement of the model chosen.