摘要:

An electron-microscopic analysis of spinal motoneurons and their synapses was carried out in a frog (Rana catesbeiana). Six different types of boutons (S, F, M, P, C and GS) have been identified. Their distribution on spinal motoneuron somata and proximal dendrites is described. The mean linear percentage of the surface area covered by boutons is 26.1 ± 1.9%. S-type boutons are preferentially concentrated on the soma and proximal dendrites. The relative number of S-type boutons (58.7%) was greater (p < 0.01) than that of F-type boutons (41.3%).This is in contrast to mammalian spinal motoneurons where F-type boutons are much more numerous on the soma than S-type boutons. F-type boutons are randomly distributed and the average ratio of S:F-type boutons is 20:14 (S:Fratio = 1.4). In contrast, M-type boutons synapse exclusively on the distal part of the dorsal dendrites and are restricted to the intermediate zone or to the dorsal horn. P-type boutons form synapses upon the large M-type boutons.The polarity of these axoaxonic synapses is always from P to M. Similarities and differences between the synaptology of frog and mammalian spinal motoneurons are discussed

ISSN:1422-6405    

DOI:10.1159/000146667

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Six hundred foramina transversaria (FT) of the axis vertebrae of 4 population groups were examined for the presence of erosion of the lateral articular mass. Of these, 127 (21%) and 72 (12%) presented with moderate and marked erosion, respectively. Evidence is presented incriminating the tortuosity of the vertebral artery as well as congenital factors in the etiology of the erosion of the FT. Attention is drawn to the possible correlation between angulation of the transverse process of the axis and erosion of the FT.

ISSN:1422-6405    

DOI:10.1159/000146668

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The effect of gossypol acetic acid on the prostate gland of the guinea pig was assessed ultrastructurally. The three lobes of the gland showed differences in sensitivity and reacted differently to gossypol treatment. In the lateral prostate, there was a reduction in the profile of the granular endoplasmic reticulum and dense secretory granules with a concurrent appearance of smaller clear granules and an increase in cytoplasmic filamentous bundles. The latter feature was similar to that of the coagulating gland. In the dorsal prostate, the general reaction was similar to that in the lateral prostate except that there was no increase in filamentous content. In the coagulating gland, there was a reduction or total disappearance of apical secretory blebs and an increase in lysosomes, a feature not found in the lateral and dorsal lobes. Damages to mitochondria were observed in the dorsal prostate and coagulating gland but not in the lateral prostate. It is concluded that gossypol affects not only the testis, but also alters the structure and functions of the prostate gland.

ISSN:1422-6405    

DOI:10.1159/000146669

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The effects of surgically induced malocclusion upon the articular disk of the temporomandibular joint in adult male rats were investigated histochemically and immunohistochemically using antibody against type II collagen. In the intermediate portion of the articular disk, the number of collagen fibers and chondrocytes was much less and the collagen fibers became more wavy, rough and irregular in surgically operated rats than in control rats. Clusters of chondrocytes were found in some experimental rats.The present experiments revealed that surgically induced malocclusion causes noticeable changes in collagen fibers and chondrocytes within the extracellular matrix of the articular disk of the temporomandibular joint.

ISSN:1422-6405    

DOI:10.1159/000146729

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The comparative morphology of the gastric mucosal microvasculature was investigated using the corrosion casting technique.The vascular pattern consisted of a hexagonally arranged capillary plexus surrounding the gastric glands and terminating in venules running perpendicular to the mucosal axis. Vessels of the pyloric antrum demonstrated an acute angle between capillaries and venules, whereas vessels of the gastroduodenal junction changed from a honeycomb pattern to a leaf-like arrangement.

ISSN:1422-6405    

DOI:10.1159/000146730

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

To determine the postnatal structural changes due to increasing articular activity, we have compared the development of the posterior and posterosuperior superficial layers of the rat mandibular condylar cartilage by electron microscopy. In contrast to the uniform development posteriorly, the posterosuperior articular zone showed an extensive remodelling process with collagen breakdown and replacement between the ages of 21 and 28 days, i.e. during weaning. Enlarged spheroid fibroblasts contained numerous micropynocytotic vesicles, collagen debris enclosing vacuoles and a nuclear fibrous lamina enveloping the nucleus; abundant electron-dense amorphous material was present in the matrix as well as covering the surface. An increased number of metabohcally active fibroblasts was supplied by the mesenchymal stem cells of the underlying chondrogenic zone.The adaptation process resulted in the replacement of small randomly oriented collagen fibers by large compact bundles running parallel to the glenoid fossa, providing protection to the condyle against excessive wear and tear during incisal biting and grinding. The direct local relationship between (ultra) structure and functional load can be utilized in experimental research on the role of biomechanical forces in mandibular condylar growth and development.

ISSN:1422-6405    

DOI:10.1159/000146731

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The mechanical events leading to locking of the human knee joint are well described in the literature, but there appears to be little information on the source of afferent feedback needed to monitor the locked joint. Human fetal popliteus muscles were studied by histological and graphic reconstruction techniques.The results showed that the muscle contained many muscle spindles.The arrangement of these receptors into complex and tandem forms seems to support the view that the popliteus muscle is capable of subserving kinaesthesia.

ISSN:1422-6405    

DOI:10.1159/000146732

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The development of the retina of the albino rat was studied after sectioning of the optic nerves on the 2nd postnatal day. The 2nd day represents a stage at which the retina shows only the ganglion cell layer clearly delineated from an undifferentiated mass. Section of optic nerves at this stage did not affect the subsequent retinal development. Both control and experimental eyes developed at the same pace. Some minor degrees of ‘retardation’ e.g. the sizes of outer segments, appeared to deviate in the experimental reti

ISSN:1422-6405    

DOI:10.1159/000146733

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Ultrastructural observations of fibroblasts from 6-week-old mouse tendons were carried out at different times after treatment with an anabolic steroid. The characteristic response of the fibroblasts involves the appearance of great numbers of intracellular lysosomes and the emergence of matrix vesicles, some of which could be identified ultrastructurally by their positive reaction for acid phosphatase as extracellular lysosomes. It is suggested that this fine structural gradient after treatment with the anabolic steroid results from, and may be directly the cause of, an increased level of cyclic AMP. The experimental design and the discussion of the findings consider, on the one hand, the use of anabolic steroid hormones in clinical practice and, on the other hand, the appearance of a collagen dysplasia in competitive sports.

ISSN:1422-6405    

DOI:10.1159/000146734

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The ontogeny of the mandibular joint and the middle ear region was studied in Erinaceus europaeus, Sorex araneus, Talpa europaea and Elephantulus rozeti. During development, a passage connection was found between the mandibular condyle and MeckeΓs cartilage that is produced by the primordium of the lateral pterygoid muscle. The articular disk is formed apart and it appears later in development

ISSN:1422-6405    

DOI:10.1159/000146735

出版商:S. Karger AG    

年代:1989

数据来源: Karger