摘要:

At 5 days post conceptionem (p.c.) shortly after implantation, giant cell transformation starts at the abembryonic pole of the blastocyst, spreading over the mural trophoblast; 1 day later, the first ectoplacental giant cells appear at the base of the fast growing ectoplacental cone (derived from the polar trophoblast). Giant cell transformation expands over its periphery. Thus, by the 8th day p.c, the conceptus is separated from the maternal tissue by a continuous layer of giant cells, variable in thickness. Giant cells reach their greatest size by 10 days p.c. in the mural trophoblast and by 12 days p.c. in the chorioallantoic placenta. They are probably no longer formed after that stage. Around the 8th day p.c, the allantois reaches contact with the ectoplacental cone, which develops into the chorioallantoic (definitive) placenta. At 9 days p.c, its four zones can already be discriminated: chorionic plate, labyrinth, junctional zone (trophospongium), and zone of giant cells, respectively. Within the next day, the chorioallantoic placental circulation is established. The yolk sac placental circulation is established by the 9th day p.c The villi of the proximal layer of the yolk sac increase in size and number, and their capillary network becomes more dense until the 12th to 14th day p.c This provides evidence that the yolk sac placenta exerts its function – to a certain extent – beyond the establishment of the definitive placenta. Around the 14th day p.c, the placentallabyrinth reaches its definitive features. Fetal capillaries in the labyrinth, branching from umbilical blood vessels within the septa of connective tissue are surrounded by trophoblast cells. They form a dense vascular network bathing in maternal blood. The structures of the placental zones remain almost the same during further development, the borders becoming sometimes little blurred. Adjacent to the chorionic plate, subchorionic clefts appear at the 14th day p.c These clefts become confluent to form the intraplacental space, regularly communicating with the yolk sac cavity. At the end of gestation (19th day p.c.) there is a considerable amount of eosinophilic material (‘fibrinoid’) between the zone of giant cells and the decidua, probably produced by the gian

ISSN:1422-6405    

DOI:10.1159/000144801

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The pattern of body weight gain, the longitudinal growth of the humerus and the changes in the width of its proximal growth plate were determined in normal ICR male mice. The respective growth rates were calculated and compared throughout the animals’ first year of life. It was found that the overall growth period can be divided into four phases which differ markedly in their growth rates. Whereas skeletal maturation is reached at the age of 20 weeks, the animals’ body weight continues to increase up to the end of the 52nd week. The humeral growth plate retains its existence and function until old age is reached, i.e. 15 months. During the period of highest growth activity extending between weanling and sexual maturation, the growth velocities of the various parameters do not coinc

ISSN:1422-6405    

DOI:10.1159/000144802

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Molar odontogenesis was studied in the hairless mouse from the initiation of the dental lamina through apposition. The dental lamina stage of the first molar was recognized on the 13th day, the bud on day 14th, cap on the 16th, bell on the 18th and apposition on the 20th day after conception. The morphology of the various stages and their temporal sequence were compared with those of other rodents.

ISSN:1422-6405    

DOI:10.1159/000144803

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The morphology of the globule leukocyte (GL) has been investigated by light and electron microscopy in normal (decidua of mouse placenta) and pathologically altered tissues (tumors of epidermis and mucous membrane in men). The results make it probable that the GL my originate from mast cells as well as from eosinophil granulocytes. The high content of basic proteins within the globules of GL has been interpreted as a nutritive function by this cell type to the surrounding tissue.

ISSN:1422-6405    

DOI:10.1159/000144804

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The author has studied the behaviour of cells from human ascitic fluid in long-term culture (5–6 months). Three cellular types are described with different morphological features, namely the cellular shape, the fashion in which the cell spreads on the glass, the nucleo-cytoplasmic ratio, the chromatin appearance and the abundance of mitochondria. The three cellular types can phagocytose, but each one in a different way. The first one phagocytoses exclusively erythrocytes ‘by contact’ without emission of pseudopods; the second one phagocytoses degenerating nucleated cells in the same way as the first; the third type phagocytoses degenerating nucleated cells by emission of long pseudopods. The origin of these three cellular types is discussed; it is felt that they are transformed mesothelial cells. According to this study, it cannot be excluded, especially for the second and the third type, that they are histiocytes coming from serous membranes. The life in vitro of the three cellular types is depending upon the composition of nourishing medium. Cells can divide by mitosis only during the first 10–15 days of culture (mitotic index 0.1–3.0‰). Nuclear amitosis, nucleolus expulsion into cytoplasm and cytoplasmatic DNA synthesis can be observed in he

ISSN:1422-6405    

DOI:10.1159/000144805

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The portion of the pre-axial region of the wing bud anterior to the cranial boundary of the skeletogenous territory of the stylo-zeugopod, according to Stark and Searls’ recent maps, was surgically isolated in chicken embryos of the stages 18–25, and autoplastically grafted to the dorsal surface of the hind-limb bud or to the trunk. In other embryos of the same stages the cranial half or the cranial two thirds of the pre-axial region mentioned were isolated and heterotopically implanted. The experimental results consistently showed that the isolate contained a variously large portion of the presumptive radius and a significant part of the proximal half of the prospective humerus. In fact, the skeletal parts mentioned did not develop in situ in the donor wing while they differentiated, in general, in the implantation site. In this regard, the present research confirms data from previous experiments showing that Stark and Searls’ maps do not offer an accurate representation of the position and of the cranio-caudal width of the presumptive areas of the skeletal pieces of the wing. Our findings seem also to indicate that the major (or longitudinal) axis of the future radius is arranged along the proximodistal axis of the wing bud throughout the developmental stages mentioned; instead, the major axis of the future humerus undergoes a gradual shift, being first (stages 18–20) arranged nearly parallel to the bud base and getting more and more parallel to the proximodistal axis of the wing bud through stages 21–24. Besides, between stages 18 and 25 the cranio-caudal width of the presumptive skeletogenous territory of the zeugopod, and to a lesser extent of the stylopod, seems to undergo a slight relative reduction with respect to the cranio-caudal thickness of the whole wing bud; this might depend on a process of aggregation of the prospective skeletogenous cells into gradually denser and more defined precartilaginous

ISSN:1422-6405    

DOI:10.1159/000144806

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The frequency of dark-cored vesicles is compared with the content in catecholamines in the adrenal medulla and carotid body of normal and reserpine-treated cats. Reserpine produces important diminution in the content of catecholamines but the frequency of the dark-cored vesicles does not parallel this descent. In the carotid body there is no relation between the content in catecholamines and the number of granules. The diameter of the dark cores does not change with the number of secretion vesicles present in normal or treated specimens. It is concluded that there is not partial discharge of the content of the vesicles. An all-or-nothing mechanism of discharge of exocytotic type is proposed.

ISSN:1422-6405    

DOI:10.1159/000144807

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The histoenzymatic characteristics of regenerating myofibers of rat masseter muscle following injection of 2% lidocaine, as well as morphometric and histochemical characteristics of the typical myofibers, were investigated. Myoblasts appeared initially by day 1 among numerous macrophages within the confines of degenerating myofibers. Myotubes predominated by the 3rd day. Complete regeneration of the muscle occurred by at least 45 days. Phosphorylase activity was absent at day 1 and reappeared by the 5th day when the regenerating myofibers showed slight activity. By the 15th day the myofiber types had partly differentiated; red myofibers were smaller and stained less intensely than the white myofibers. Myotubes stained uniformly for succinic dehydrogenase activity from 3 until 5 days. After 5 days this staining increased gradually. Myofiber types began differentiation by 15 days and were fully differentiated by 45 days. ATPase activity was barely evident by 1–3 days. This activity appeared uniformly low up to 5 days and increased to an intensity comparable with that of the typical myofiber by 15 days. Slight leucine aminopeptidase activity occurred in macrophages 1 day following injection. By 3 days this activity appeared in the remaining myoblasts and in the myotubes. Some activity was found in the fibroblasts. This staining intensity at 5 days .was equal to that of earlier lesions. A trace of this activity was found at 7 days, and none at 15 days. Glucose-6-phosphate dehydrogenase activity was present in the macrophages by day 1. It increased by 3 days and occurred mainly in myoblasts and myotubes. This activity decreased by 5 days, and none was found by 7 day

ISSN:1422-6405    

DOI:10.1159/000144808

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Using Micropaque (crystallized barium sulphate) in a gelatinous medium of a certain viscosity, with a fluorescent pigment in the solution, we obtained a mixture with a fluidity adequate to a vascular injection; this injection is performed with a constant pressure, the values of which are kept between limits near the values of the physiological arterial pressure. We found several types of arterio-luminal vessels with different calibres: some of them with a calibre of 200 µm, some others of the intermediate type with a calibre between 100 and 200 µm, and others, which we call arterio-Thebesian vessels, originating in arteriolar branches opening in the Thebesian veins. At last, we have the arterio-sinusoido-cavitary vessels opening in the ventricular cavities by several orifice

ISSN:1422-6405    

DOI:10.1159/000144809

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In five female pigs, weighing approximately 100 kg, laparotomy was made under surgical anesthesia. One kidney was removed for immersion fixation and enzyme histochemistry, while the other kidney was fixed by vascular perfusion without prior interruption of the blood flow. A step-by-step description is given of the perfusion procedure, which requires three assistants. Prior to perfusion, heparin was given in order to prevent intravascular coagulation. 1% glutaraldehyde in Tyrode’s solution was used as perfusion fluid. Polyvinylpyrrolidone 2.5% was added in order to adjust the colloid osmotic pressure of the perfusion fluid to that of the blood. Perfusion was maintained for 5 min. The tubules appeared with open lumina, and the proximal tubular cells had evenly arranged brush borders and both lateral and intercellular spaces were narrow and of constant widt

ISSN:1422-6405    

DOI:10.1159/000144810

出版商:S. Karger AG    

年代:1977

数据来源: Karger