摘要:

The study of the pancreas development in Pleurodeles waltlii Michah (amphibian urodele) shows the following characteristics: 1) The dorsal rudiment is formed the first, even before the irrigation of the tree producing branchial buds (end of stage 30). This rudiment is formed by isolation of cells rich in vitellus from the dorsal wall of the archenteron. The ventral rudiment, which is massive and more developed on the right side than on the left, appears only a few hours later. The two rudiments fuse at the eclosion time (after stage 35). The elements of the exocrine pancreas, which are the first formed, take place little before the eclosion (stage 33b). They come from the transformation of the cells rich in vitellus, with embryonic character. Solid masses of these cells are first formed and then hollowed in tubules which secondarily join the central pancreatic canal of rudiments. The endocrine elements, which are as rare in the larva as in the adult, appear only after the eclosion. The B cells are formed first (stage 35).

ISSN:1422-6405    

DOI:10.1159/000144637

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Histochemical demonstration of β-glucuronidase was carried out in the normal and regenerating tail of the house lizard, Hemidactylus flaviviridis. Greater enzyme activity was particularly discernible in the stratum germinativum of the skin of the normal and fully regenerated tail. During regeneration most of the cellular elements of the blastema and the differentiating regenerate exhibited enzyme activity. Distribution of the enzyme β-glucuronidase is correlated with the high degree of cellular proliferation. The role of the enzyme in the catabolism of mucopolysaccharides is also implicated during the wound-healing phase. In the full-grown regenerate the intensity and distribution of the enzyme activity were found to be the same as those observed in the normal tai

ISSN:1422-6405    

DOI:10.1159/000144638

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Adrenal glands of eight Indian species of birds, namely Columba livia, Passer domesticus, Corvus splendens, Acridotheres tristis, Acridotheres ginginianus, Milvus migrans, Francolinus pondicerianus and Bubulcus ibis were examined during the sexually active and inactive phases of their annual reproductive cycles. Excepting A ginginianus and M. migrans, among members of either sex of the remaining six species the weight of the adrenal gland increases during the period of sexual activity. Histologically, the interrenal tissue of these birds could be divided into a peripheral subcapsular zone and a central zone. The cytochemical content of these two zones varies between sexual activity and inactivity. In sexually active birds of both sexes, interrenal cells of the central zone exhibit an increased concentration of alkaline phosphatase, glycogen, acid mucopolysaccharides and gross lipids, while in the subcapsular interrenal cells there is a prominent increase of ascorbic acid content. Cytochemical contents of chromaffin cells remain unchanged except acid phosphatase, which increases during the sexually active phase.

ISSN:1422-6405    

DOI:10.1159/000144639

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A fiber count analysis was performed with the electron microscope on the facial nerve trunk distal to the geniculate ganglion in seven mice. On an average, 4,836 (93%) of the total nerve fibers (5,201) were myelinated and 328 (6.3%) unmyelinated. The large part of the nerve consisted mostly of large myelinated fibers (large-fiber group). The small part of the nerve consisted of small myelinated and unmyelinated fibers (small-fiber group). The fiber constitution of the small-fiber group in the nerve was more like that in the intermediate nerve than that of the small-fiber group in the motor root of the facial nerve. Thus, it is postulated that the nerve fibers of the small-fiber group in the facial nerve trunk distal to the geniculate ganglion may be derived from the intermediate nerve, and that the nerve fibers of the small-fiber group in the motor root of facial nerve may course to the greater petrosal nerve.

ISSN:1422-6405    

DOI:10.1159/000144640

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Mouse embryos, gestation days 10 and 11, were fixed by the method of Luft (ruthenium red). At the ultrastructural level, luminal epithelial cell membranes of Rathke’s pouch and the neural tube were coated with a continuous, electron-dense layer of 100–700 Å thickness. The biological property of this surface coat is discu

ISSN:1422-6405    

DOI:10.1159/000144641

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Electron-microscopic, histochemical and endocrinologic study of aldehyde-fuchsin-positive (Gomori-positive; GP) grains of rat brain periventricular glia (GP glia) was carried out. GP structures appear as a population of osmiophilic particles, which is heterogeneous in both shape and size. Laminar structures interspersed with fine granular material were seen in the GP granules. No activity of the lysosomal and mitochondrial enzymes could be observed. The reaction for peroxidase was also negative. The GP material was stained with PAS and Ziehl-Nielsen. There are apparently no lipoid inclusions in the GP grains. The primary red-orange fluorescence distinguishes the GP glia from other structures in the rat brain. So GP grains are a specific cytoplasmic formation having some similarity to lipofuscin. There was a considerable decrease in GP grains after administration of estradiol in ovariectomized rats and also in pregnant rats. Dopamine administration and starvation caused some reduction in GP grains. In the rat hypothalamus, distribution of the main mass of GP glia corresponds with the so-called hypophysiotropic area. The possible participation of GP glia in the neuroendo-crinological process is discussed.

ISSN:1422-6405    

DOI:10.1159/000144642

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

A reliable method of sex identification in pig embryos at sexually indifferent and early differentiated gonadal stages (age 21–26 days) was developed in association with ultrastructural studies on gonadal development and differentiation. The routine carbolfuchsin staining for the sex chromatin and the quinacrine mustard dihydrochloride staining for the fluorescent Y chromosome were not successful when applied to interphase cells. Therefore, it was necessary to develop a method for complete chromosome preparations. Head, heart and liver proved to have a sufficiently high spontaneous mitotic rate without any mitogenic stimulation. The tissues were suspended in the culture medium. Optimal conditions for colchicine treatment and hypotonization were tested and the details of the procedure are reported. This direct method yielded adequate metaphase plates for chromosome analyses in pig embryos. Because no culturing is used, the method is rapid and artefactual changes in the chromosomes during stimulated cell divisions in vitro are avoide

ISSN:1422-6405    

DOI:10.1159/000144643

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

Sexual dimorphism in the surface markings of the basilar part of the occipital bone of 34 male and 46 female dog’s skulls were studied with the following results: 1 of the 34 male skulls showed a female type surface marking, 4 of the 46 female skulls showed surface markings of the opposite sex, while 2 of the male and 3 of the female skulls could not be classified as belonging to either type, so that 10 out of the 80 skulls could not be identified correctly, indicating that 87.5% of the skulls could be identified positively. Considering that there are hardly any sexual differences in the other surface markings or in the dentition of the dog’s skull, these findings may be of some help in sexing the skull of the

ISSN:1422-6405    

DOI:10.1159/000144644

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

(1) Simple esterase activity has been demonstrated in the gustatory epithelium of man and dog by the simultaneous coupling azo dye technique using α-naphthol and naphthol As acetate. Unfixed cryostat and fixed paraffin sections were used. (2) A peculiar pattern of simple esterase activity was encountered in which – contrary to what was to be expected – the taste bud-carrying papillae showed a very poor reaction while there was a gradual increase in the enzyme intensity as the epithelium was traced away from these papillae. (3) It seems that among the reported differences between simple esterases and cholinesterases is this differential activity in relation to the gemmal system. (4) A peculiar difference in the enzyme activity was reported between the unfixed cryostat and the fixed paraffin sections in the human mate

ISSN:1422-6405    

DOI:10.1159/000144645

出版商:S. Karger AG    

年代:1976

数据来源: Karger

摘要:

156 abdominal preparations were explored by arteriography, corrosion and dissection. The ileocolic artery is the most constant collateral of the superior mesenteric artery. It provides a ramus colicus which is often confused with a true arteria colica dextra. The a. colica dextra, arising on the superior mesenteric artery, is found in only 13% of the abdominal preparations. The PNA ‘a. colica media’ covers a system of individually varying vessels: a. colica media, common stem of r. anguli coli and r. coli transversi; a. anguli coli, a. coli transversi; a. colica sinistra accessoria and a. coli transversi accessoria. Both mesenteric arteries may be linked by an intermesenteric arch (1

ISSN:1422-6405    

DOI:10.1159/000144646

出版商:S. Karger AG    

年代:1976

数据来源: Karger