摘要:

The structure of various sense organs and endocrine glands was examined in the stripe-faced dunnart, Sminthopsis macroura. This marsupial has the shortest gestation known for all mammals, 10.5–11 days. The morphology of the anterior pituitary, adrenal gland, olfactory epithelium, Merkel cells around the mouth and the utricle of the vestibular system of S. macroura was similar to that observed in other newborn marsupials. These structures are thought to be required by the newborn to transfer from the uterus to the pouch. The stage of development of the urinary system, the semicircular canals of the vestibular system, eyes and lungs was slightly different to that of other newborn marsupials. These structures are thought to have secondary importance in allowing the newborn to reach the teat. Although marsupials display variation in gestation length and produce newborn of differing body weights, there is little difference in morphology between various newborn marsupial speci

ISSN:1422-6405    

DOI:10.1159/000147549

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

This paper deals with the expression and distribution of casein kinase 2 (CK-2) subunits in mouse embryos at different developmental stages. Expression was investigated at the mRNA level of CK-2 α- and β-subunits by in situ hybridization and distribution at the protein level by immunohistochemistry using CK-2-α and CK-2-β-specific antibodies, respectively. In general both methods gave similar results. In earlier stages of mouse embryonic development (day 10.5 after coitus) CK-2 was more expressed in neuroepithelia than in all other tissues. From day 11.5 after coitus on, high expression of CK-2 was detected in all epithelia. From day 16.5 on, all tissues and anlagen of the fetus involved in organogenesis revealed a higher CK-2 expression as compared with secondary mesenchyma. The only difference between in situ hybridization and immunocytochemistry was observed in the skin. Transcripts of CK-2 were found mostly in the basal layer of the epidermis and in the nuclei of keratinocytes, whereas CK-2 protein was almost exclusively found in the cytoplasm of epidermal ce

ISSN:1422-6405    

DOI:10.1159/000147550

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

We have demonstrated that fetal hypophysectomy (hypox) induces deficiencies in skin and adipose tissue development and that chronic thyroxine (T4) treatment either normalizes or enhances skin and adipose tissue development in hypox fetuses. Since hypox also induces deficiencies in muscle development we report herein results of a histochemical and biochemical analysis of muscle development conducted in studies of T4-treated hypox fetuses. Pig fetuses were hypo-physectomized on day 70 of gestation and treated with T4 during two periods, i.e. 70–90 days and 90–105 days gestational age, by implanting slow-release T4 (15 mg) pellets in the lateral musculature of the hind limb. Blood, muscle and other tissue samples were obtained upon removal of fetuses at days 90 and 105 of gestation. Weights of hypox, control and T4-treated hypox fetuses were similar at the end of the early period (70–90 days) whereas T4 significantly depressed body weight (p < 0.05) during the later period (90–105 days). Muscle weights, protein, DNA and RNA concentrations and muscle fiber size were not influenced by hypox or T4 treatment. Hypox-induced deficiencies in muscle capillary-to-fiber ratios, percentage of dry matter and general morphology were normalized by T4 (p < 0.05) during both treatment periods. Lipid deposition (staining) and histochemical reactivity for an oxidative marker (NADH-TR) were enhanced (p < 0.05) by T4 during both treatment periods as revealed by computer-assisted image analysis. Histochemistry for myofibrillar (acid) ATPase showed that the hypox-impaired type II to type I fiber type conversion was not influenced by T4 treatment. Muscle developmental traits enhanced or normalized by T4 were directly or indirectly related to lipid and/or oxidative metabolism. Effects of T4 on muscle and other tissues indicate, therefore, that thyroid hormones may be key regulators of oxidative and/or lipid metabolism in the neonatal

ISSN:1422-6405    

DOI:10.1159/000147551

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The early development of the lens was examined, using 36 externally normal human embryos at Carnegie stages 13–23 (4 to 8 weeks of gestation). Twenty-two embryos were sectioned serially and stained with periodic acid-Schiff and a modified method of PAS. In 14 embryos, not only the differential distribution of glycogen but also the ultrastructural change in the developing lens, with special reference to junctional complexes, were examined electron microscopically. At stage 15, when the lens vesicle was formed, glycogen was observed in the cytoplasm of the lens epithelium, especially in the posterior lens epithelium. From stages 16 to 18, when the posterior lens epithelium was differentiated into the primary lens fibers and elongated toward the anterior lens epithelium, the amount of glycogen increased in the basal cytoplasm of the primary lens fiber, where the intracellular organelles, such as the tubular vesicles, mitochondria and multivesicular bodies, began to aggregate. At stage 20, when the lens cavity was obliterated, glycogen was also present in the anterior lens epithelium. At stage 21, as the formation of the secondary lens fibers proceeded, glycogen was noted in the secondary lens fibers in the equator region. These findings suggest that the distribution of glycogen is associated with the formation of the primary and secondary lens fibers. In addition, we provide additional information that a lot of glycogen is distributed in the region where many intracellular organelles aggregate in the embryonic lens vesicle

ISSN:1422-6405    

DOI:10.1159/000147552

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The occurrence and ultrastructural morphology of somatomammotroph cells, in the anterior pituitary tissue of the goat, is studied using fluorescence microscopic double staining and two methods of double immunogold staining combined with electron microscopy. Under the fluorescence microscope numerous monohormonal cells, either mammotroph cells (prolactin, PRL, cells) or somatotroph cells (growth hormone, GH, cells) are observed, but cells containing both hormones (somatomammotroph or SMT cells) are scarce. SMT cells do not differ ultra-structurally from monohormonal cells, and the cytoplasm contains two populations of granules, each reactive only for one of the antisera, either antisheep GH or antisheep PRL.

ISSN:1422-6405    

DOI:10.1159/000147553

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Changes in intracellular gonadotropin-releasing hormone (GnRH) immunoreactivity (GnRH-IR) in pituitary gonadotrophs were assessed by the use of a semi-quantitative immunocytochemical method in male rats undergoing various manipulations known to greatly modify gonadotropin secretion. In basal conditions, immunoreactive GnRH was localized in the cytoplasmic matrix, the secretory granules and the nucleus of these cells. Following intravenous stimulation with GnRH (100 ng i.v.), the GnRH-IR increased rapidly in all these three sub-cellular compartments, peaking at 15 min. In untreated, long-term castrated rats, GnRH-IR increased both in the basal state and after administration of GnRH. Injection of the castrated rats with testosterone propionate reduced the observed GnRH-IR to the level observed in intact rats. Acute or chronic treatment of castrated rats with a potent GnRH antagonist rendered GnRH-IR completely undetectable in all the three previously positive subcellular compartments of gonadotrophs, and GnRH-IR did not reappear after stimulation with GnRH. In sum, the fact that modifications of GnRH immunoreactivity are observed in rat gonadotrophs: (1) confirms the GnRH internalization process; (2) suggests different sites of action for GnRH within the cell, and (3) demonstrates rapid clearance of intracellular GnRH after stimulation.

ISSN:1422-6405    

DOI:10.1159/000147554

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The calcification levels of the mandible and the temporal bone of human fetuses, which ranged from 12 to 32 weeks of gestation, were systematically investigated with a soft X-ray analyzer linked to an image analyzer. The profile of the condylar process (head) revealed high levels of calcification, in contrast to that in the mandibular fossa of the temporal bone. The basal portion of the condylar process and the mandibular notch exhibited moderate calcification from 12 weeks of gestation. The weight and the cross-sectional areas of the muscle and the muscle fibers in masticatory muscles (masseter, temporal, medial, and lateral pterygoid muscles) are all increased gradually during development from 12 to 32 weeks of gestation. These changes in calcification and in cross-sectional area of muscle suggest that muscle development may be related to bone calcification during formation of the mandible.

ISSN:1422-6405    

DOI:10.1159/000147555

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The submandibular-sublingual complex (SSC) was studied in vivo by magnetic resonance imaging (MRI) at 4.7 and 7.05 Tesla in rat and mouse. A correlation was found between histology and MRI signal. The mainly mucous sublingual gland emitted a more intense signal than the mainly serous submandibular gland. Ventral to the glands, cutis, subcutaneous adipose tissue and two planes of muscular tissue separated by connective laminae were visible in vivo. Autopsy and histology confirmed the in vivo description provided by MRI. The reactivity of the salivary system after pharmacological stimulation was studied in mice at 7.05 Tesla. Stimulation of salivary secretion by pilocarpine nitrate injected in the subcutaneous space ventrally to the SSC resulted in an augmentation of the salivary liquid visible in the oral cavity by MRI. The diffusion of pilocarpine nitrate in the connective tissue located ventrally the SSC and in the glandular parenchyma was also followed in vivo. These results show that MRI is a potentially useful tool for studying the salivary glands in vivo.

ISSN:1422-6405    

DOI:10.1159/000147556

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The course of the right recurrent laryngeal nerve (RLN) within the vagus nerve was examined under the light microscope, using horseradish peroxidase. In the higher cervical vagus, i.e. from the base of the skull to the level of the carotid bifurcation, the recurrent laryngeal nerve fibres formed on average 5-6 small separate bundles (15–40 µm in diameter); in the middle cervical vagus, on average from the level of 8-14 mm caudally from the bifurcation, there were fewer bundles with a diameter range of 10-50 µm; in the lower cervical vagus, indicated as being from 14-26 mm caudally from the middle cervical vagus, the bundles merged into a single larger bundle (50–7

ISSN:1422-6405    

DOI:10.1159/000147557

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

An analysis of the lengths of spinal cords was conducted using data from 129 adult Thais, 73 males and 56 females, who ranged in age from 20 to 95 years with an average age of 66.6 ± 16.6 years. The lengths of spinal cords ranged from 30 to 49 cm with a mean of 40.8 ± 3.2 cm. The average cord length in males (42.3 ± 2.5 cm) was significantly greater than that in females (38.9 ± 3.1 cm; p 0.05). The length of the vertebral column was also measured in 16 cases. It ranged from 64.5 to 70.5 cm with an average of 68.4+3.5 cm. There was a significant correlation between the length of the spinal cord and the length of the vertebral column (p < 0.

ISSN:1422-6405    

DOI:10.1159/000147558

出版商:S. Karger AG    

年代:1994

数据来源: Karger