The effect of various fixation procedures on the digestability of sialomucins with neuraminidase

Improvement in identification of pro-estrous mice by using a novel method of detecting vaginal mucous cells

Accurate identification of the murine estrous cycle using vaginal exfoliative cytology is the initial and crucial step for controlled reproduction of this species. However, it is generally difficult to discriminate each stage of the cycle, and thus to select pro-estrous mice for mating. To increase the accuracy of identification of the pro-estrous stage, we re-evaluated the vaginal fold histology and modified the method of exfoliative cytology. Tissue fixation using methanol in Carnoy's solution but not paraformaldehyde, combined with Alcian blue staining but not the conventional Giemsa staining, resulted in better manifestation of mucosal cell layers in the vaginal epithelium just above the keratinized layer. This mucous layer in the fold histology was found to form specifically in the pro-estrous and late di-estrous stages, and the mucous cells exfoliated in smear samples only in the pro-estrous stage. This novel method was found, by a blinded test, to increase the rate of accurate identification of the pro-estrous stage compared to the conventional method (80% vs 50%). Consistent with this finding, the mating experiment with "pro-estrous" females selected by the novel method revealed a significantly higher success rate than that with the conventional method (78.0% vs 47.5%). Thus, our study demonstrates vaginal exfoliative mucous cells as a better potential marker to detect the "receptive" state of female mice that leads to an improved success rate of mating.

[Histochemical investigations on sialic acid containing compounds in the CNS of teleosts (author's transl)]

By means of histochemical experiments the qualitative (microphotographs) and quantitative (cytophotometry) distribution of sialic acid containing compounds was investigated in the mesencephalon and cerebellum of Carassius carassius. 1. The perikarya of nerve cells are especially stained by means of Azur A. 2. Nerve fibres, on the other hand, showed positive reactions with colloidal ironhydroxyd (CIH). 3. In different structures of the CNS the intensity of CIH-staining is decreased up to about 55% following treatment with neuraminidase. 4. There are no differences in the reactions of 7 degrees C as compared to 20 degrees C adapted animals.