[Quantitative analysis of the mosaic formation of neurons of the neocortex and hippocampus of the mouse]. / Kolichestvennyi analiz mozaichnogo formirovaniia neironov v neokortekse i gippokampe u myshei.

Computer analysis of the maps of distribution of intensively labelled neurons (ILN) in the frontal sections of area 6 of the frontal neocortex and area CA 1 of the dorsal hippocamp was performed in 1-day-old mice who received a single injection of 3H-thymidine on the 13th-17th day of embryogenesis (E 13-E 17). It has been revealed that ILN are distributed in rather close, vertically oriented groups. In mice exposed to isotope in E 14-E 16, the average number of ILN in a group was 4.44 +/- 0.25 for area 6 and 4.35 +/- 0.16 for area CA 1. The data available have confirmed an earlier postulated hypothesis on the discrete arrangement of neurogenesis loci in the ventricular zone of the embryonic brain. Additional calculations have allowed to conclude that in E 14-E 16 period the locus of the ventricular neocortex during one mitotic cycle produces 7-9 cells starting the neuronal differentiation, while during the whole period of neurogenesis in the neocortex the column consisting of 84-108 neurons is formed, which is close to the number of neurons in a minicolumn of the neocortex (110 cells).

[Space-time sequence and mosaicism of neurogenesis in the CA1 field of the mouse hippocampus]. / Prostranstvenno-vremennaia posledovatel'nost' i mozaichnost' neirogeneza v pole CA1 gippokampa u myshei.

Pregnant CBA mice were given a single injection of 3H-thymidine (3H-T) (10 microCi/g) on days 11-19 of pregnancy. The mouse progeny was sacrificed on the first day of postnatal life. Brain was embedded into paraffin and durcupan. Radioautographs of paraffin and semithin sections were prepared and employed for mapping the site of intensely labeled neurons (ILN) in the CAI area of the hippocampus (H). ILN appeared in the CAI area after 3H-T injection, namely on embryonic day 12 (E 12). The ILN number reached a maximum after isotope injection on 2 14-15 and then dramatically fell down. The neurogenesis in the suprapyramidal layer of the CAI area slightly outstripped the neurogenesis in the pyramidal and infrapyramidal layers. At early times of the experiment the CAI area exhibited the predominance of single ILN, whereas at late times paired ILN prevailed. That fact might be linked with the replacement during the neurogenesis of asymmetric critical mitoses of the germinative neuronal precursors by symmetric critical mitoses. Analysis of the ILN distribution in the CAL area revealed mosaic clusters of ILN alternating with unlabeled or mildly labeled neurons. Those groups were most remarkable in mice injected with 3H-T on E 14 and E 15. The mosaicism of the neurogenesis in the H is regarded as the result of heterochronous neuronal production by local parts of the germinative zone, each of which builds up a separate radial segment of the H.

[Quantitative evaluation of cell proliferation and death in the horn of Ammon and dentate gyrus of the developing hippocampus in the mouse]. / Kolichestvennaia otsenka proliferatsii i gibeli kletok v ammonovom roge i v zubchatoi izviline razvivaiushchegosia gippokampa u myshei.

The mitotic and pyknotic indices were counted in the local germinative zones of Ammon's horn and dentate gyrus of normal mice from embryonic day 18 (ED 18) to postnatal day 60 (PD 60). The local germinative zone of Ammon's horn (the suprafimbrial zone) forms from ED 16 but the first pyknoses appear in it from ED 20. After a rapid increase of the mitotic and pyknotic indices with a maximum reached on PD 3 there is a sharp decrease of their values corresponding to the reduction of the suprafimbrial zone. The local germinative zone of the dentate gyrus is generated from ED 14, however pyknoses appear from PD 1. The greatest values of the mitotic and pyknotic indices fall within PD 3. Later on the values of both indices gradually decrease, however, they are sufficiently pronounced even on PD 60. It is suggested that the mitotic death by means of pyknotic degeneration is connected with elimination of the spontaneous mutations of glial precursors in the germinative zones of the brain.

[Spatial localization of proliferating and dying cells in the developing hippocampus in the mouse]. / Prostranstvennaia lokalizatsiia proliferiruiushchikh i gibnushchikh kletok v razvivaiushchemsia gippokampe myshei.

Mapping on arrangement of mitoses (M) and pyknoses (P) has been performed in the mouse developing hippocamp. Analysis on the M arrangement confirms the data known on the hippocampal germinative zones and time of their reduction in the mouse ontogenesis. Previously unknown germinative zone of Ammon's horn has been revealed--the suprafimbrial zone that exists since the 16th day of embryogenesis up to the 7th postnatal day. Analysis on the P arrangement demonstrates that they appear in the hippocampal germinative zones during the perinatal periods. Localization of the P corresponding to that of the M agree with the data on "mitotic" death of the germinative and glial cells in the developing brain.

[Use of carnitine for stimulation of the growth and development of the mouse brain in undernourishment in early postnatal ontogeny]. / Primenenie karnitina dlia stimuliatsii rosta i razvitiia golovnogo mozga myshei pri nedoedanii v rannem postnatal'nom ontogeneze.

The authors studied the possibilities of using carnitine for stimulation of the mouse brain development under malnutrition in the early postnatal ontogenesis. The results indicate that addition of carnitine to the diet during food rehabilitation stimulates the growth of the body and brain mass, increases the neocortex, hippocamp, cerebellum and the size of neuronal bodies in these structures, removes the effect of retarding the growth of neuronal processes and noticeably decreases the rate of dystrophic changes in the brain structures under study. Thus, the disturbances of the mouse brain development caused by malnutrition are completely eliminated after the animals are fed a full-value diet containing carnitine.

[Analysis of cell proliferation and death in the subependymal and subgranular germinative zones of the brain of mice subjected to malnutrition in early postnatal development]. / Analiz proliferatsii i gibeli kletok v subépendimnoi i subgranuliarnoi germinativnykh zonakh myshei, podvergnutykh deistviiu nedoedaniia v rannem postnatal'nom ontogeneze.

The mitotic index, index of cell labelling with 3H-thymidine, picnotic index and parameters of mitotic cycle were determined in the subependyme and subgranular germinative brain zones, as well as the index of labelling of glioblasts in the neocortex of the intact 20 days old mice and mice subjected to malnutrition from the 10th till the 20th day of life. The subependyme and subgranular zones did not differ by the generation time and periods of mitotic cycle but the subgranular zone had a lower proliferative pool. Upon malnutrition the parameters under study in both the germinative zones suffered no marked changes but the number of dying cells with picnotic nuclei forming at the stage of mitosis increased greatly; the number of proliferating glioblasts in the neocortex decreased markedly. A conclusion is drawn that the model of malnutrition used in the present work influences the cell production in the germinative zones in young mice mainly by means of intensification of mitotic cell death.