摘要:

Iron-deficient female Wistar rats were fed a diet which contained 0.5% 3,5,5-trimethylhexanoyl (TMH)-ferrocene over a 57-week period. The state of iron deficiency was characterized by means of the absence of stainable iron in the bone marrow. After the first days on the iron-enriched diet, ferritin-containing siderosomes were found, in numerous erythroblasts up to orthochromatic nor-moblasts and in reticulocytes, i.e. the dispensed iron was used for haemoglobin synthesis. After 1 week the first macrophages showed a positive Perls’ Prussian blue reaction. In the cytoplasm they stored the iron in the form of free ferritin molecules and lysosomally as aggregated ferritin and/or haemosiderin. The iron loading of the macrophages increased in both of the storage qualities proportionally with duration of the feeding period and reached a maximum after 38 weeks. Final stages showed extremely iron-loaded macrophages with high concentrations of free ferritin molecules and large siderosomes, partially flowing together to still greater units. Iron deposits within endothelial cells of bone marrow sinusoids can be observed for the first time after 4 weeks. In these cells the iron is stored as ferritin in siderosomes of relatively small and uniform size; free ferritin molecules in the cytosol were of only slight concentration. The TMH-ferrocene model of iron overload shows in the bone marrow: (1) an unimpeded utilization of the iron component for erythropoiesis, (2) development of excessive iron overload of the bone marrow in macrophages and endothelial cells of sinusoids and (3) a pattern of distribution of iron as seen in secondary haemochromatosi

ISSN:1422-6405    

DOI:10.1159/000147318

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Coitus is a unique physiological event which may result in internal fertilization, whereby active allogeneic spermatozoa are presented to the female host which can invade her tissues. Sterile coitus on the other hand, stimulates the uterine cervix in the rat and induces a physiological state of pseudopregnancy which interrupts the normal pattern of the oestrous cycle and establishes a persistent dioestrous state. This state is hormonally controlled and in its early stages is not dissimilar from that of true pregnancy. Pregnancy hormones are known to influence the immunological status of the female. Thymic observations during early pseudopregnancy showed interstrain differences in weight, cell content and thymocyte proliferation. Pooled data indicated increased cell density on days 3, 4 and 5 of pseudopregnancy associated with a peak of mitotic activity on day 3 in both strains. The timing of this proliferative activity seems to reflect the needs of the immune system in its putative response to mating and implantation.

ISSN:1422-6405    

DOI:10.1159/000147319

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Using enzyme and immunohistochemical methods on whole-mount preparations and cryostat sections, a morphologic and semiquantitative study was performed of the nervous tissue in the appendix and the ileum (areas with and without Peyer’s patches) of the rabbit. The plexus submucosus externus (Meissner) consists of a network of small ganglia, vaguely associated with the vascular sub-mucosal plexus. From the nerve cell bodies, cell processes occasionally penetrate the lymphoid follicles at the junction between the mucosa and the submucosa while other extensions form a dense plexus in the lamina propria of the mucosa. No nerve fibers are present in the dome of the follicles. The plexus submucosus internus (Henle), consisting of large cell bodies and large processes, closely follows the blood vessels. The numeration of the nerve fibers of the sub-mucosal plexus endorses the histological finding that the appendix is a richly innervated lymphoid organ. In addition, the plexus myentericus (Auerbach) of the appendix is a network of small meshes, while in the ileum, in the area of Peyer’s patches, the same plexus is composed of a network with large meshes. These differences point to a higher density of innervation in the appendix. Yet a specialized anatomic distribution of the innervation of lymphoepithelial structures cannot be demonstra

ISSN:1422-6405    

DOI:10.1159/000147320

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Eighty-eight Long Evans/Turku rats were used in the study. The effect of the articulatory function on the mandibular condyle was observed histologically during normal growth, when the rat is changing its diet from milk to whole pellets as a part of weaning. Six animals each were killed at the age of 10, 15, 20, 25, 30,35, 40 and 50 days for histological tissue processing. For further information, 30 animals were fed a soft diet (6 animals each were killed at the age of 25 30, 35, 40 and 50 days), and 10 animals were fed hardened pellets (2 animals each were killed at the ages of 25, 30, 35, 40 and 50 days). An even and regular transition from mesenchymal cells via immature chondroblasts into mature chondroblasts and hypertrophied chondrocytes was found at 10,15 and 20 days during normal growth and also at 25, 30, 35, 40 and 50 days when animals were fed a soft diet. This maturing process appeared to be disturbed at the age of 25, 30, 35 and 40 days in the superior aspect of the condyle in animals fed ordinary pellets. The density of the mesenchymal cell layer was decreased, and the amount of intercellular matrix seemed to be elevated in mesenchymal and intermediate cell layers. These features were later manifest deeper in the cartilage as acellular regions and as cell clusters. The changes were similar but more severe when the animals were fed hardened pellets. The thickness of the cartilage was decreased, and chondrocytes appeared small and surrounded by abundant amounts of extracellular matrix in these animals at the age of 50 days. The findings are suggestive of features in the condylar cartilage that have been attributed to the articular cartilage of long bones. They seem to indicate that, while the condylar cartilage is obviously under loading during functioning, the articulatory function may suppress the growth of the condylar cartilage by changing its properties towards those typical of the purely articular cartilage. The functional loading during normal growth is obviously close to the maximum that the mandibular condyle is capable of sustaining.

ISSN:1422-6405    

DOI:10.1159/000147321

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The differentiation of extraocular muscles was studied immunohistochemically in externally normal human embryos (Carnegie stages 13-23), using antibodies to carbonic anhydrase (CA) III and β-enolase as the markers of type 1 and type 2 muscle fibers, respectively. At stage 18, some myoblasts were immunoreactive to β-enolase antibodies, however, CA-III immunoreactivity was not observed around the optic vesicle. At stage 20, CA-III immunoreactivity appeared in some muscle fibers of extraocular muscles. From stage 21 to stage 23, CA-III-immunoreactive fibers increased and almost equalled the number of β-enolase-immunoreactive fibers. These findings suggest that CA-III-immunoreactive type 1 fibers appear in the late stage of myogenesis compared with β-enolase-immunoreactive type 2 fib

ISSN:1422-6405    

DOI:10.1159/000147322

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

113 femurs and 111 tibias originating from chick embryos 8-21 days after incubation were injected with Indian ink and made transparent. The origin and distribution of cartilage canals are described. The existence of a pattern of segmental distribution, atypical canals and anastomosis between epiphysial canals and diaphysial marrow processes is reported.

ISSN:1422-6405    

DOI:10.1159/000147323

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The cross-sectional area of a particular ligament is an important characteristic in order to establish the biomechanical properties of this ligament. Calculations of the cross-sectional areas of the ligaments of the wrist joint are made from two three-dimensional models. It is discussed that differences between the presented and the scarcely published data on cross-sectional areas are the result of different divisions of the wrist-joint ligamentous complex into separate ligaments.

ISSN:1422-6405    

DOI:10.1159/000147324

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Surgical reduction of luteal tissue to about 20% of its total mass on day 5 pc was found to maintain gestation till term. A high degree of fetal loss was, however, evident. An identical surgical manipulation at the end of maximal luteal maturity, that is, on day 16 pc, resulted in normal maintenance of gestation. Fetal growth and their survival rate were found to be comparable to controls. An exclusive surgical extirpation of corpora lutea, on the other hand, either on day 16,17,18 or 19 was found to cause 100% fetal loss by day 23. However, progesterone replacement therapy concurrently with surgical luteal ablation till day 20, or surgical extirpation of the entire luteal mass when shifted on day 20, led the pregnancy to term. Present experimental findings, therefore, suggest that only about 20% of the functionally matured luteal mass until day 20 is essentially enough to maintain an ideal pregnancy status till term.

ISSN:1422-6405    

DOI:10.1159/000147325

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The melanocytes are acutely sensitive to a single pulse of UV and express neural differentiation. The present work was undertaken to observe whether the melanocyte can sense variations in the duration of UV exposure. Whole skin organ cultures from marginal zone in vitiligo were exposed to a single pulse of UV, 30, 60, 90 and 120 s each. Catecholoxidase levels in the marginal melanocytes and the volume of melanocytes were used to calculate and quantitate the changes in enzyme production. The melanocytes’ dendricity, volume and enzyme production increases with the duration of UV exposure. This sensitivity of the marginal melanocytes, to changes in the duration of UV exposure, simulates the coat color changes in weasels and the polar fox exposed to extreme variations in the day/night cycles. The UV response is associated with proliferation of melanocytes as it is G2-phase dependent. Thus the melanocytes form a UV-sensitive neural network responding to annual changes in the photoperiodicit

ISSN:1422-6405    

DOI:10.1159/000147326

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The development of the mesonephros and metanephros was examined in the marsupial Northern native cat, Dasyurus hallucatus, from birth through to the end of lactation. The mesonephros was present at birth, reached a maximum volume 11 days after birth and had regressed completely by day 30. The metanephros was present on day 2; glomeruli were first seen on day 8, and nephrogenesis continued until day 89 post partum. The newborn native cat is at a very primitive stage of development compared to other marsupials. However, at weaning, like other marsupial species, the native cat has developed a fully morphological and functional urinary system.

ISSN:1422-6405    

DOI:10.1159/000147327

出版商:S. Karger AG    

年代:1992

数据来源: Karger