摘要:

Ultrastructural investigations give evidence of secretion channels in the mucous sheet of the gastric mucosa of the cat. These channels are filled with basophilic mucin which may transport the gastric acid to the luminal surface.

ISSN:1422-6405    

DOI:10.1159/000147152

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

‘Seams’ of the root furcation with multiroots in rat molar teeth termed by Lester and Boyde were investigated using transmitted light and scanning electron microscopy in the formation process. The seam was formed in the junctional line of Hertwig’s epithelial root sheaths. The seam formation will be classified into three types in the initial stage based on the position of the epithelial root sheaths approaching each other: (1) the close junction or the very narrow slit or gap formed between them, (2) the clear gap containing mesenchymal cells and (3) the gap containing one blood vessel. When the roots were formed, the seam was formed as follows: (1) the slight ridge composed of the cellular cementum, (2) the proliferation or the depression in the dentine formation and (3) the accessory or lateral canal of the root. These structures were variously combined with each other into one seam, although the slight ridge was very c

ISSN:1422-6405    

DOI:10.1159/000147153

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

With the aim to verify the changes that a reduction of the oxygen rate may elicit in the morphological pattern of the human chorionic villi, a new experimental procedure has been suggested. Chorionic villi from human early placentas were incubated in Dulbecco’s modified medium of Eagle in the presence of oxygen, air or CO2 at a gas pressure equal to 0.7 atm. The specimens were fixed, dehydrated and embedded in resin, and semithin sections were obtained. Using an image analyser, the thickness of the trophoblastic layer and the mean radius of the villi were evaluated and the results submitted to a statistical analysis. The results show a decrease in the ratio thickness of the trophoblast/mean radius of the villus, directly proportional to the reduction of the oxygen percentage in the employed gases. The interesting conclusions demonstrate that the changes which affect the chorionic villi occur very early and are easily evaluable with quantitative methods; a clinical interest in the use of the proposed quantitative procedure can be emphasize

ISSN:1422-6405    

DOI:10.1159/000147154

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

In order to elucidate the existence of gender-related variations in both growth hormone (GH) release and the activity of somatotropic cells following bilateral adrenalectomy, a morphometric analysis was performed on GH-immunoreactive cells from adult male and female rats after bilateral adrenalectomy, correlating the findings with the serum levels of the hormone. The results obtained were compared to those found in untreated animals. Bilateral adrenalectomy was seen to induce a decrease in serum GH levels (p < 0.01) in male rats; this was accompanied by a significant decrease in cellular area (p < 0.01), cytoplasmic area (p < 0.05) and nuclear area (p < 0.01) and by a decrease in the cytoplasmic immunoreaction intensity of GH cells. By contrast, the above-mentioned changes did not appear in the female rats. These results suggest that the action of glucocorticoids on the synthesis and release of GH depends on the sex of the animal.

ISSN:1422-6405    

DOI:10.1159/000147155

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

A rare and hitherto not reported case in which a branch of the vagal nerve communicated simultaneously with the facial and the glossopharyngeal nerves was encountered in the body of a Japanese male cadaver in an anatomy class. This vagofacial-vagoglossopharyngeal (X. VII-X.IX) communicating branch was found to issue from the vagal nerve truck in close association with the pharyngeal branches (rami pharyngei nervi vagi) bifurcating soon into a vagofacial (X. VII) and a vagoglossopharyngeal division (X. IX). The X. VII division coursed forward and reached the posterior belly of the digastric muscle; after entering this muscle, this division broke up into filaments to communicate with the ramus digastricus of the facial nerve which was found to play an equivalent role in making the vagofacial ansa. The X.IX division, in contrast, took its course medially to reach the stylopharyngeal muscle. After entering this muscle, the X.IX division communicated with the stylopharyngeal branch of the glossopharyngeal nerve, which was found to be the equivalent to the X.IX division; these two form together the vagoglossopharyngeal ansa. Therefore, it could be concluded that the X. VII-X.IX communicating branch constitutes the vagal moieties of the vagof acial as well as the vagoglossopharyngeal ansae. The background of the appearance of the communicating branches observed in this report is discussed in the text from the developmental viewpoint on the basis of the findings obtained in chick embryos stained in whole mounts with anti-neurofilament protein antibody.

ISSN:1422-6405    

DOI:10.1159/000147156

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The structure of the mandibular periosteum in rabbits of different ages has been studied by different histological staining techniques and polarization microscopy. The periosteum consisted of two layers. From the inner, cellular layer the functional state could be determined. A reproducible pattern of resorptive and depository areas was found on the bony surface. In the outer, fibrous periosteal layer, collagenous and elastin fibers were running in distinct directions. The masticatory muscles appeared to be attached directly endomysially or indirectly endomysially, via the perimysium or tendinous attachment. From the periosteal structures and the characteristics of muscular fiber attachments to the bone and periosteum, especially in the ramal and condylar areas, it could be concluded that a mechanical influence of the periosteum on condylar growth is very well possible, which will probably vary during life. The masticatory muscles seemed to be only of minor influence in condylar activity.

ISSN:1422-6405    

DOI:10.1159/000147157

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

In order to obtain more insight into the physiologic mechanism of endochondral ossification, histological changes occurring in the mandibular condylar cartilage of growing rats fed on a low-calcium diet were investigated by light and electron microscopy. Twenty-three-day-old rats were fed on a normal diet or a low-calcium diet for 8 weeks. For the histological observations the mandibular condyles were dissected from each animal at 1, 2, 4, 5 and 8 weeks after the initiation of the experiment. Histological changes occurring in the mandibular condylar cartilages of the rats fed on a low-calcium diet were as follows: (1) narrow proliferative and mature cell zones and a wide hypertrophic cell zone, (2) inhibition of development of cell organelles in the mature chondrocytes, (3) decrease in dead cells in the proliferative zone, (4) decrease in glycogen accumulation in the chondrocytes and (5) inhibition of calcification in the extracellular matrix of the hypertrophic cell zone. Additionally at the end of the experimental period, the following findings were observed: (1) appearance of small light cells in the mature cell zone and the hypertrophic cell zone and (2) decrease in proteoglycan granules and appearance of large collagen fibrils in the pericellular region of the hypertrophic cell zone.

ISSN:1422-6405    

DOI:10.1159/000147158

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Light- and electron-microscopic examination of arterioles, venules and capillaries of the eyes of several mammalian species has shown that the microfibrils of ocular elastic tissue attach to microvascular basement membranes throughout the uvea (iris, ciliary body, choroid) and optic nerve. Although described sporadically in prior investigations, this report shows that the connections are a common feature of the mammalian eye. The connections appear most numerous at venules and capillaries and are sparse at arterioles. The connections may provide a mechanism by which perivascular elastic tissue influences microvascular function, e.g. the control of blood pressure in them or their response to changes in intraocular pressure.

ISSN:1422-6405    

DOI:10.1159/000147159

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The vestibular apparatus of the opossum was examined shortly before and immediately after birth. A band of about 20 sensory cells was observed within the forming utricle by 24 h prior to birth. Stereocilia projecting from the apices of the sensory cells appeared intimately associated with a well-defined population of overlying otoliths. These morphological observations suggest that a functional utricle may be present at the time of birth and together with other senses (tactile, olfaction) may aid the newborn of this species in its migration from the birth canal to the pouch.

ISSN:1422-6405    

DOI:10.1159/000147160

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

This study has attempted to research, in detail, the dimensions and form of the malleus, and to indicate possible differences with regard to race, sex and side of origin (left or right). The ossicles were obtained from 75 adult cadavers and the dimensions were determined with the aid of a reflection microscope. Clear statistically significant differences were found between the Negroid and Caucasoid races, as well as between the right and left ossicles. No meaningful differences were determined between male and female ossicles.

ISSN:1422-6405    

DOI:10.1159/000147161

出版商:S. Karger AG    

年代:1991

数据来源: Karger