摘要:

In this study, an ultrastructural and immunohistochemical examination was carried out on the presence of an ‘atrial-natriuretic-peptide (ANP)-like factor’ in the myoblasts of the brachial myotome of chicken embryos at Hamburger and Hamilton stages 17 ± to 19. The results of the immunohistochemical study indicate that, at these stages of their development, the myoblasts of the brachial myotome show ANP immunoreactivity. The ultrastructural analysis of the myoblasts shows the presence of ‘granules’ or ‘secretory vesicles’, similar to the secretory granules which contain natriuretic peptides. The demonstration of immunoreactivity to ANP in the myotome and the specific localization of secretory vesicles in myoblasts, as the first evidence relating ANP with skeletal muscle development, reveal a new site at which an ANP-like factor may be synthesized. The hypothesis of a paracrine and/or autocrine function(s) during myogenesis

ISSN:1422-6405    

DOI:10.1159/000147607

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The ultrastructure of the stromal cells of the thymuses of chick embryos from the 13th to 19th day of incubation was investigated. At the 13th day, the non-lymphoid elements consist mainly of undifferentiated and epithelial cells. The dominant cystic cells are organized to form intra- and intercellular cysts and cleft-like spaces. By the 15th day, cysts are more conspicuous, and the cystic cells are marked by an increase in cytoplasmic organelle content. Isolated foci of cystic cells with no apparent connections to cysts are also observed. Myoid cells, characterized by the presence of myofibrils, are identifiable at this stage. Endocrine-like cells show synthetic and secretory activities and are distributed in cystic epithelium or among other cell types. Dendritic cells and macrophages are also observed among the other cells. Between the 15th and 19th day, there is a further increase in size and frequency of the cysts. Myoid and endocrine-like cells are also more prevalent.

ISSN:1422-6405    

DOI:10.1159/000147608

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

This study examines the normal postnatal (p.n.) development of the Mongolian gerbil’s vagina from birth to the age when consistent cyclic changes of the estrus occur. At birth, the Müllerian vagina has a lumen and is lined by a pseudostratified or 2- to 3-layered epithelium. The cells contain large amounts of glycogen. The sinus vagina forms a solid plate and contains hardly any glycogen. During the first few p.n. days the cell layers separate, and the newly formed lumen becomes continuous with the Müllerian vagina. Only a vaginal closure membrane persists. Between p.n. days 10 and 15 the epithelium increases in height reaching 2–5 cell layers. The amount of glycogen diminishes, but in the luminal cells the first mucous granules develop. Leukocyte diapedesis starts, and immature Langerhans cells become discernible. Between p.n. days 18 and 30 the apical cells become mucified, and some shedding of these cells begins. Between p.n. days 36 and 45 bundles of keratin filaments appear in many of the luminal mucous cells intermingled with the mucous granules. In the middle layers keratin filaments, keratohyalin granules and membrane-coating granules indicate the beginning of the keratinization process. Diapedesis of leukocytes may lead to cell aggregations below top layers. By day 50 the shedding of the mucous cell layers reveals the underlying keratinized cell layers which then become exfoliated. The first steps of the estrous cycle show a heterogeneous pattern. At about p.n. day 60 the cycle becomes establ

ISSN:1422-6405    

DOI:10.1159/000147609

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The localization of lipids in the endometrium of virgin and 6- to 9-day-pregnant mice was detected by histochemical methods. Total lipids (as shown by staining with Sudan black) and phospholipids containing choline (PCC) were detected. Sections subjected to reactions that have been proposed for the demonstration of vitamins E and D and cholesterol gave negative results. In the virgin animals, lipids were found in epithelial cells but not in the endometrial stroma. On the other hand in the pregnant animals, the endometrial stroma contained both Sudan-black-stained lipids and PCC. Maximal staining was reached on day 8 of pregnancy. The staining was more conspicuous in the more differentiated decidual cells adjacent to the embryos than in the less differentiated predecidual cells. The nondecidualized stroma, situated peripherally near the myometrium did not stain for lipids. In the cytoplasm of decidual cells the reaction for PCC was observed in the form of granules, which were often arranged in groups surrounding the nuclei. We suggest that decidual cells store PCC to be mobilized as a precursor for mediators of decidualization, such as prostaglandins, that would act as paracrine inducers of the decidual reaction.

ISSN:1422-6405    

DOI:10.1159/000147610

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

With the deprivation of both circulating androgen (CA) and luminal androgen (LA; orchiectomized goats), the epithelial height (EH) in regions I–IV of the epididymis was reduced to 28, 67, 58 and 56% of that of controls, respectively, but it was increased to 109% of that of controls in region V. Similarly, the volume density of epithelium (VDE) in regions I–V was reduced to 33, 49, 45, 41 and 70% of that of controls, respectively. Conversely, in the absence of LA only (extratesticular-rete-ligated goats), while both EH and VDE were reduced to almost 50% of those of controls in region I, they remained similar to those of controls in other regions. The morphological changes in the epithelium such as cytoplasmic regression, loss of stereocilia and disorderly arrangement of epithelial cells were maximal in region I, moderate in regions II–IV and minimal in region V. Testosterone treatment appreciably reduced the degenerative changes caused by orchiectomy in all regions except region I where the restorations were marginal at best. Hence, the results suggest a differential epididymal response to androgen deprivation. Whereas the LA and/or other rete fluid components seem essential for maintaining the epithelial structure of region I, the CA alone can maintain, at least partially, the epithelial structure of regions II–IV and almost completely that of r

ISSN:1422-6405    

DOI:10.1159/000147611

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Mandibular condylar cartilage (MCC) of growing mammals contains four layers of cells which display a series of increasingly differentiated phentoypes and which culminate in a terminally differentiated cell that produces a calcified matrix. In this study, MCC cells were placed into culture in Dulbecco’s modified Eagle’s medium containing 10% fetal bovine serum and 50 µg/ml ascorbic acid. After 12 h in culture, transmission electron microscopy revealed the presence of multiple cell types that underwent differentiation with additional time in culture. By 7 days, fusiform-shaped cells were seen that contained numerous actin-like cytofilaments and micropinocytotic vesicles characteristic of myofibroblasts. Chondroblast-like cells were also observed. By 10 days, without addition of β-glycerophosphate or dexamethasone, these cellular events culminated in the formation of mineralized nodules containing matrix vesicles. The nodular surface at day 13 consisted of two or more layers of myofibroblast-like cells, while the deeper zones of the nodule contained cells displaying a morphology typical of calcified hypertrophic chondroblasts. These ultrastructural observations are consistent with the hypothesis that cells from the MCC are capable of recapitulating in culture the maturational events seen in vivo. This cell culture model may be useful for investigating cell-mediated cartilage calcification without the addition of exogenous phosphate or other regulatory fa

ISSN:1422-6405    

DOI:10.1159/000147612

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The pulmonary air space between the large bronchi at the hilum is supplied by small daughter bronchi that stem from axial main branches. In this study, we evaluated the morphological appearance of the pulmonary artery which corresponds to the daughter bronchus using an inflated-fixed lung specimen. In contrast to the relationship in the subpleural area, the pulmonary artery did not follow the corresponding airway in the area supplied by the daughter bronchus. Only at the tip of the terminal bronchiole was a close association found. Each terminal bronchiole showed a tendency to receive its blood supply from the nearest parent branch of the pulmonary artery.

ISSN:1422-6405    

DOI:10.1159/000147613

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

In a Japanese female cadaver, the occipital portion of the trapezius muscle (the cleido-occipitalis) was separated from the rest of the muscle by a triangular gap that resulted from a deficiency of the upper two thirds of the cervical portion on both sides. The right cleido-occipitalis blended distally with the cervical fibers of the trapezius and had a normal insertion into the clavicle. The left cleido-occipitalis intermingled partially with the reduced cervical portion, and some of the conjoint fibers formed an independent accessory slip whose tendon inserted into the posterior aspect of the junction of the middle and medial thirds of the clavicle. The other conjoint fibers inserted into the clavicle and scapula as usual. This anomalous morphology may be attributed to a secondary degeneration of a portion of the trapezius anlage concomitant with an abnormal segregation of another portion during development.

ISSN:1422-6405    

DOI:10.1159/000313645

出版商:S. Karger AG    

年代:1994

数据来源: Karger