摘要:

Incidental to studies of keratinization of the equine hoof wall, annular gap junctions were found in the stratum spinosum of the intertubular horn of the stratum medium. Adjacent cells of the stratum spinosum showed extensive gap junctions, and often local invaginations of one cell into another were bound by gap junctions. It is proposed that these invaginations become detached from the cell surface to form the annular gap junctions. Formation of annular gap junctions may be a means of disposing of plasma membrane in response to changes in cell volume or shape occurring in keratinization. Interiorization of gap junctions may also facilitate cell movement, and perhaps may act to reorganize desmosome-tonofibril arrangements by budding off appropriate interdesmosomal areas, thus drawing the desmosomes closer to one another.

ISSN:1422-6405    

DOI:10.1159/000145719

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The collagen content of the mouse uterus increases during pregnancy and rapidly decreases to the level of nulliparous mice within a few days post partum. Most of the hydroxyprohne in the uterine collagen had disappeared by day 3 post partum. During postpartum involution the hydroxyprohne concentration in both the serum and blood clot was not higher than in nulliparous mice. The total hydroxyprohne content in the liver, spleen and thymus was significantly increased during postpartum involution. These results indicate that materials derived from the breakdown of uterine collagen are rapidly removed from the blood stream by reticuloendothelial clearance.

ISSN:1422-6405    

DOI:10.1159/000145720

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The development of muscles from the dorsal side of the forelegs from 13- to 21-day-old rat embryos was investigated under a light microscope. The muscle blastemata and individual muscles were stained in situ with the cholinesterase technique. The first muscle blastemata are visible on the early day 13. It appears that mainly myotubes are stained. The antebrachial and brachial extensor muscles form separated anlagen which connect on the late day 13 in the proximal region of the extensor carpi ulnaris muscle. The individualization of the muscles in a muscle blastema takes place on days 13 and 14. On day 15 all extensor muscles are visible. However, at this time the inserting points of some of these muscles are not yet visible after staining with alcian blue. On the early day 16 the motor end-plates are conspicuous. Due to the content of unspecific cholinesterase in rat embryos the tendons are also stained on day 16. Muscles and tendons remain stainable until birth. In addition to the muscles also the nerves, especially the epifascial nerves, stain very well with the acetylcholinesterase reaction.

ISSN:1422-6405    

DOI:10.1159/000145721

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The trigeminal nerve has motor, intermediate and sensory roots in the dog. The motor root is composed of two bundles: the medial and ventral. The ventral motor root emerges from the pons, forming the common root with the sensory, and then is separated from it to run along with the medial motor root which separately exits from the pons as the ordinary motor root. The mesencephalic root fibers of the trigeminal nerve are investigated in the dog, using the myelin sheath degeneration technique. Degenerated fibers are observed numerously in the ventral motor root and moderately in the medial motor root, and are traced to the mandibular branch of the trigeminal nerve. Some degenerated fibers are observed in the sensory root and they seem to pass through the Gasserian ganglion to enter the ophthalamic and maxillary branches. No degenerated fibers are found in the intermediate root.

ISSN:1422-6405    

DOI:10.1159/000145722

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

To elucidate longitudinal tubular bone growth patterns in relation to craniofacial development, nine 4-week-old male New Zealand white rabbits received tantalum implants in the calvarial bones and in the proximal and distal tibial epiphyses. The animals were examined by roentgen stereophotogrammetry. The rapid growth rate deceleration pertained to all growth regions studied, except the sagittal suture. A brief period of under-nutrition highlighted the parallel in growth rates between the frontonasal suture (associated to the facial skeleton) and the tibia. The neurocranial coronal suture exhibited a different growth pattern, presumably related to neural tissue expansion, which was also observed to rapidly react to nutritional deficiency. Tibial growth was found to sensitively reveal influences of somatic development. Hence, it might be used to optimize growth evaluations.

ISSN:1422-6405    

DOI:10.1159/000145723

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Ectopic (intrauterine and under the renal capsule) pituitary transplantation induced a high incidence of adenomyosis with subserous nodules in both SHN and SLN strains of mice. Early signs of the development were the invasion of stromal fibroblasts into the myometrium along the branches of blood vessels, followed by uterine gland invasion of the musculature to the serosa. Pituitary grafting did not modify the effects of carcinogens on the uterus. Mechanisms of the development of adenomyosis and hormonal milieu facilitating these pathological changes of the uterus are discussed.

ISSN:1422-6405    

DOI:10.1159/000145724

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

On corrosion casts of the bovine choroidal vessels, the vascular architecture was investigated by means of scanning and corresponding transmission electron microscopy. Complete filling of the vessels produced close-fitting replicas. Thus, based on different luminal structure, the arteries and veins in the lamina vasculosa could be easily distinguished. The branches of these vessels were followed to the choriocapillaris. The complete pattern of afferent and efferent vessels provided the opportunity to establish a scheme of choroidal microcirculation. The choriocapillaris in the bovine as a freely communicating network is subdivided into star-shaped areas of roughly hexagonal form. On the boundaries of these areas the afferent vessels (arterioles) – arranged at regular distances – join the choriocapillaris, whereas drainage of the choriocapillaris is effected by a single efferent vessel (venule) in the center of each a

ISSN:1422-6405    

DOI:10.1159/000145725

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

entionogenesis of permanent tooth germs in kittens was examined in a transmission electron microscope. Crystals of various sizes (3–30 Å in width) appeared in the matrix vesicles. Electron diffractional features revealed that crystal size in electron micrographs reflected various stages of crystal growth. Pairs of small crystals and dislocated crystals were observed in some crystal-containing matrix vesicles. However, these matrix vesicles were not observed in unmineralized matrix just adjacent to calcifying fronts and in mineralized dentin. Furthermore, long crystals were abundant in mature dentin. These findings suggest that crystal growth in matrix vesicles is due to fusion and that dentin maturation progresses through crystal growth along the long ax

ISSN:1422-6405    

DOI:10.1159/000145726

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The sequential development and growth of the subcortico-cortical fibres have been studied by means of acetylcholinesterase (AChE; acetylcholine acetylhydrolase; EC 3.1.1.7) histochemistry on the serial sections obtained from brains of human fetuses ranging from 10 to 28 weeks of gestation. It was found that thalamic and basal telencephalic fibres approaching the fetal auditory cortex have very strong AChE reactivity during a prolonged period of growth. In the youngest fetuses (10.5 weeks) a prominent fibre system was seen emerging from the ventroposterior thalamic territory while the auditory neopallium was free of AChE staining. In older fetuses (16–18 weeks) AChE-positive fibres originating in the ventroposterior thalamus and basal telencephalon penetrate the ‘subplate layer’ of the auditory cortex. On the basis of AChE reactivity of the ‘subplate layer’ the auditory cortex can be delineated from the surrounding neocortical areas. In the oldest fetuses (22–28 weeks) AChE-positive fibres of thalamic origin penetrate the developing cortical plate of the audi

ISSN:1422-6405    

DOI:10.1159/000145727

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Thin sections of newborn rat incisors were examined by tracer experiments and freeze-fracture replication in order to clarify the morphology and permeability of ameloblast junctional complexes in the maturation stage. Ameloblast junctional complexes consisted of gaps and tight junctions at the proximal and distal ends. Whereas the proximal junctional complexes sealed extracellular spaces incompletely, the distal ones formed complete, belt-like barriers around the cell. Tight junctions of these junctional complexes, however, were composed of both continuous and discontinuous rows of particles with various spaces among them. Intravenously injected horseradish peroxidase (HRP) reached the enamel surface through the extracellular spaces among ameloblasts and was absorbed by ameloblasts of the ruffled borders. Pinocytosis and transcellular migration of HRP could not be demonstrated in maturing ameloblasts except in the ruffled border zone.

ISSN:1422-6405    

DOI:10.1159/000145728

出版商:S. Karger AG    

年代:1983

数据来源: Karger