Mitotic activity of adrenal medullary cells in the mouse at different ages and following unilateral adrenalectomy

Summary The number of mitoses as well as the number of the cells of the adrenal medulla was determined in the mouse at various ages and after unilateral adrenalectomy. It was found that a decrease in the mitoses and an increase in the cell number occurs up to 4 months. In 12-month-old rats, mitoses, although rare, are still present. No changes in the mitosis and cell number was observed after unilateral adrenalectomy.     

Opposite effects of vasotocin injected intrapituitarly and intraventricularly on corticotropin release in mice.

A single injection of 10 pg synthetic arginine vasotocin into the pituitary significantly potentiated adrenal hypertrophy produced in male mice by unilateral adrenalectomy, whereas the same concentration injected into the 3rd ventricle produced adrenal atrophy.     

Decidual cell reaction in ovariectomized-adrenalectomized rats

Enhancement of decidual cell reaction (DCR) following adrenalectomy was reversed by corticosterone as well as indomethacin. The results suggest the adrenal involvement in DCR through uterine prostaglandin production.     

Mitosenverteilung in der larvalen Rumpfepidermis vonSalamandra maculosa Laur.

Summary In the larval epidermal trunk region ofSalamandra maculosa, the total number of mitoses of both sides is approximately the same. This applies to the differentiated Leydig cells as well as to the rest of the epidermis cells.With respect to the meristic segmentation of the trunk, we find within the single segments a regular rise of the mitotic rate, which alternates from one side to the other.From the total number of mitoses found in the epidermis of the trunk, approximately 40% can be accounted for to the dorsal and 60% to the ventral region of the trunk. The number of cells is the same for both the ventral and dorsal region.     

Immunohistochemical study of the pars intermediate of the mouse pituitary in different experimental conditions.

Alpha-MSH, beta-MSH and ACTH have been localized in the cells of hypophyseal intermediate lobe by fluorescence histoimmunological technics. Elaboration and excretion of these polypeptides are enhanced after dehydration or adrenalectomy. The most evident variations are seen with alpha-MSH and ACTH after dehydration, with beta-MSH after adrenalectomy.     

Änderung der Wachstumskinetik von Ehrlich-Aszitestumoren verschiedener Ploidie nach Röntgen-Bestrahlung

Summary The effect of irradiation (500 R) on the cell cycle of the diploid (EAT_dipl.) and the hypertetraploid (ELT) Ehrlich ascites tumor growing in the peritoneal cavity of male NMRI mice has been studied autoradio-graphically by the double labelling technique (H³- and C¹⁴-thymidine) and the method of labelled mitoses. The results suggest that the proliferation kinetics of tumor cells after irradiation depends on the type of tumor cell strain tested. Identical results were obtained after application of the alkylating agent cyclophosphamide (100 mg/kg).     

Observation of an endothelial mitosis in a mesenchymal capillary of the scala tympani during the development of the guinea-pig

Summary A mitosis in an endothelial cell during the development of the cochlea of the guinea-pig is described; the occurrence of endothelial mitoses is discussed.     

Effect on macrophages of acute stress induced in mice by local irradiation]

In examining the role of radiation in inducing immunosuppression in tumor-bearing Mice it has been shown that the experimental acute stress inadvertently generated by the procedure is profoundly immunosuppressive. It would appear that monocytes under the influence of glucocortico?ds are sequestered in the spleen. This monocyte immobilisation leads to rapid suppression of local inflammatory reactions including delayed hypersensitivity. The increased number of marcrophages in the spleen is co-incident with non-specific non T cell splenocyte anti-tumour activity. Stress induced suppression of inflammation is prevented by previous adrenalectomy and restored by hydrocortisone.     

Acute changes in dopamine metabolism in the medio-basal hypothalamus following adrenalectomy

During the first hour following adrenalectomy the alpha-MPT-induced disappearance of dopamine was increased in the arcuate nucleus compared to that in sham-operated rats. In a number of other brain regions of both adrenalectomized and sham-adrenalectomized rats only stress-induced changes were observed in catecholamine utilization. These data suggest that corticosterone selectively modulates dopamine utilization in the medio-basal hypothalamus.     

Beeinflussung des Generationszyklus und seiner Teilphasen bei Ehrlich-Aszitestumoren verschiedener Ploidie durch Cyclophosphamid

Summary The effect of the alkylizing agent cyclophosphamide (100 mg/kg i.p.) on the cell cycle of the diploid (EAT dipl.) and hypertetraploid (ELT) Ehrlich ascites tumor growing in the peritoneal cavity of male NMRI-mice has been studied by autoradiography with H³- and C¹⁴-thymidine (double labelling technique and method of labelled mitoses). The results suggest that the proliferation kinetics of tumor cells after administration of cyclophosphamide is dependent essentially on the type of tumor strain tested.     

A new variety of acute non-promyelocytic leukemia with t(15;17)]

Three cases of a new variety of acute leukemia have been reported. The main features were: hyperleukocytosis made of large-sized blasts with a double shaped nucleus, few or no granulations in the cytoplasm, and in a few cell faggots or unique Auer rods; mycloperoxydase reaction was positive. This feature was associated with disseminated intravascular coagulation syndrome and t(15;17)(q22;q21) translocation in the majority of mitoses.     

Die DNS-synthese im rattenherzen als funktion des lebensalters. Autoradiographische untersuchungen mit3H-thymidin

Summary The percentage of DNA-synthesising heart muscle nuclei of white rats (³H-thymidine, autoradiography) decreases rapidly during the first month of life reaching a minimum at the fourth month. From then up to 27 months the number of labelled muscle nuclei remains rather constant. Also in nuclei of connective tissue the³H-thymidine labelling index decreases as a function of the rats age. The number of mitotic figures is always about 10 times lower than labelled nuclei. Mostly in heart muscle cells they occur as collapsed mitoses never leading to cytoplasma division¹⁴.     

Immunohistochemical study of the pars intermedia of the mouse pituitary in different experimental conditions

Summary -MSH, -MSH and ACTH bave been localized in the cells of hypophyseal intermediate lobe by fluoresence histoimmunological technics. Elaboration and excretion of these polypeptides are enhanced after dehydration or adrenalectomy. The most evident variations are seen with -MSH and ACTH after dehydration, with -MSH after adrenalectomy.     

Going vertical: functional role and working principles of the protein Inscuteable in asymmetric cell divisions

Coordinating mitotic spindle dynamics with cortical polarity is essential for stem cell asymmetric divisions. Over the years, the protein Inscuteable (Insc) has emerged as a key element determining the spindle orientation in asymmetric mitoses. Its overexpression increases differentiative divisions in systems as diverse as mouse keratinocytes and radial glial cells. To date, the molecular explanation to account for this phenotype envisioned Insc as an adaptor molecule bridging between the polarity proteins Par3:Par6:aPKC and the spindle pulling machines assembled on NuMA:LGN:Gαi. However, recent biochemical and structural data revealed that Insc and NuMA are competitive interactors of LGN, challenging the simplistic idea of a single apical macromolecular complex, and demanding a revision of the actual working principles of Insc.     

De la réaction mitotique de l'épiderme de la tétine de cobaye à la suite d'applications répétées de diverses substances

Summary (1) The majority of substances tested produced a weaker mitotic reaction of the epidermis of the guinea pig nipple after 3 applications (24 h intervals) of the same substance than after a single application.(2) This decrease in the ability of the epidermic cells to be divided has to be attributed, it seems, to a habit-forming processus and not to an exhaustion of the cells; indeed after two applications of geraniol, the application of a substance of different nature, Hormoestrol, produced in the nipple epidermis a mitotic flare up as intense as that obtained in the epidermis of a nipple not previously treated.(3) Aldehyde C₉ alone, among the substances tested, does not produce a decrease of epidermic mitoses after three applications but induces cellular alterations.     

Über eine selektive Mitosehemmung und -schädigung bei jungen Ratten durch Synthalin A

Summary A single subcutaneous injection of synthalin-A does not affect the cytoplasma ofA-cells in pancreatic islets of the rat during the 1^st–5^th day of life, in contrast to adult animals. Selective action was found on mitoticA-cells: reduction of mitotic frequency to 25% of the normal rate, and pathological mitoses in the sense of the so-called primary effect. The mitoses ofB-cells, exocrine pancreatic cells and intestinal epithelia seemed to be unchanged, although the mitotic rate was higher than inA-cells.     

Zur DNS-Synthese in Spermatogonien hypophysektomierter Ratten

Summary Atrophy of the testes was induced by hyposectomy of rats. While the differentiation of spermatids and of spermatozoons was inhibited, DNA-synthesis and mitoses of the spermatogones continued.     

Testicular compensatory hypertrophy in the unilaterally adrenalectomized lizardMabuya carinata (Schn.)

Unilateral adrenalectomy in recrudescent and breeding phases of the reproductive cycle caused atrophic changes in the ipsilateral testis, shown by inhibition of spermatogenic and steroidogenic activity of the ipsilateral testis. The contralateral testis showed compensatory hypertrophy. Unilateral adrenalectomy in regressing and quiescent phases of the reproductive cycle did not induce compensatory hypertrophy in the contralateral testis although there were atrophic changes in the ipsilateral testis.     

Acute changes in dopamine metabolism in the medio-basal hypothalamus following adrenalectomy

Summary During the first hour following adrenalectomy the -MPT-induced disappearance of dopamine was increased in the arcuate nucleus compared to that in sham-operated rats. In a number of other brain regions of both adrenalectomized and sham-adrenalectomized rats only stress-induced changes were observed in catecholamine utilization. These data suggest that corticosterone selectively modulates dopamine utilization in the medio-basal hypothalamus.Acknowledgment. The skilful technical assistance of Ms Joke Van Put, Ms Henny De Vos Burchart-Lodewijks and Mr Henk Spierenburg is gratefully acknowledged.     

Antigen-induced mitosis in liver macrophages of immunized mice

Résumé Des souris ont été immunisées avec l'albumine du sérum humain dans l'adjuvant complet de Freund. Un jour après une injection de rappel de l'antigène la taille des mitoses, parmi les macrophages du foie dépasse celle des mitoses des souris témoins.

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This work was supported by grants from the National Health and Medical Research Council of Australia and from the Postgraduate Medical Foundation of the University of Sydney. We thank MissMaria van Deventer for skilled assistance.