摘要:

The anlage of the cervical vertebral column of a human embryo has been investigated (9 mm CRL, Carnegie stage 16). The nuclear density in the axial mesenchyme increases rhythmically from cranial to caudal. This phenomenon superimposes a metameric pattern on the blastema. Furthermore, cell formations are shaped by the orientation of the mesenchymal cells. The name ‘formationes quasi distensae’ is proposed for this system. The anlage of the atlas shows a distinct mesenchymal anlage of a vertebral body. The conclusion is drawn that the dens axis is predominantly formed out of the anlage of the atlas body. The opinion that man does not show an anlage of the atlas body can no longer be sustai

ISSN:1422-6405    

DOI:10.1159/000146445

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The prenatal development of the human submandibular gland has been investigated in 26 fetuses from the 10th week of gestation to full term. At 10–12 weeks, the glandular elements (primitive ducts and acini) were immature and surrounded by a loose mesenchyme. The acinar cell population increased gradually till the age of 32 weeks, and the rate of increase was diminished thereafter. At 16 weeks, intercalated and striated ducts were distinguished and their number increased till the age of 32 weeks when their number seemed to be stabilized. The development of the granular convoluted tubule cells from the proximal segments of striated ducts occupied the later stages of development. They appeared around the age of 20 weeks and proceeded till full term. At birth, the gland appeared devoid of mucous acini and fat cells and the secretory end-pieces were of the serous type. During the second trimester, periodic acid-Schiff- and alcian blue-positive secretory materials appeared in the epithelial cells of both ducts and acini, and in their lumina. This secretory activity was transitory and disappeared around the age of 28 weeks.The possible function of these secretory products is discusse

ISSN:1422-6405    

DOI:10.1159/000146446

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Paraganglia were consistently found at the bifurcation of the superior laryngeal nerve of the rat. Ultrastructurally the paraganglionic cells resembled the type I and type II cells of the carotid body. The dense-cored vesiculated type I cell was found most frequently, whereas the type II cell represented 10–25% of the cell population. The volume density of the dense-cored vesicles was found to be 3.5 ± 0.5, which is about half as much as that found in the recurrent laryngeal nerve and about twice of that found in the carotid body. Atotal of 24,634 dense-cored vesicles were measured, and the mean diameter was calculated to be 113.8 ± 4.9 nm. Based on the median vesicle profile diameter, only one type of dense-cored vesicle cell was fo

ISSN:1422-6405    

DOI:10.1159/000146447

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Two hearts of human twin embryos at 14 mm C-R (stage 18) were studied by means of light microscopy and quantitative methods. The serial sections of the embryos, 5 μm thick, were projected by using a microprojector for the measurement of the cardiac diameters and cardiac profile areas.The calculated heart volumes were 8.34 and 8.45 mm3, respectively. Cardiac volume is more accurate than linear.measurement to establish quantitative development of the heart. It can also be considered an accessory index for embryonic classification.

ISSN:1422-6405    

DOI:10.1159/000146448

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

A study is made of the number of pineal gland synaptic ribbons in 35 maleWistar rats over a 24-hour period during the months of September and February, in correlation to the serum melatonin levels during the same periods and photophases.The results of the study confirm those reported by others authors and suggest that the synaptic ribbons may be the stimuli-transmitting organs facilitating pineal secretory function.

ISSN:1422-6405    

DOI:10.1159/000146449

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Respiratory cilia of mice from 3 days prior to birth till 21 days after birth were examined by freeze-fracture preparations for the determination of the frequency and size of the intramembranous particles (IMPs). Dependent on the age of the animals different numbers and sizes of IMPs were found. A significant drop in total number of IMPs in all diameter classes was most evident from the 19th day of gestation to the 20th day (1 day prior to birth), followed by a marked rise between embryonal day 20 and the 1st postnatal day. The results were discussed with regard to morphological and functional changes in the respiratory system prior to and after birth.

ISSN:1422-6405    

DOI:10.1159/000146450

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The effect of ethanol on hepatocytes from pregnant minipigs and their half-term fetuses was studied with the aid of morphometric methods. In the pregnant minipigs the hepatocytes of the ethanol-treated animals showed a significant increase in the volume density of mitochondria, autophagic vacuoles, Golgi complexes and smooth endoplasmic reticulum, and a significant decrease of glycogen. In the half-term fetuses the hepatocytes of ethanol-exposed animals showed no significant change in the volume density of mitochondria, peroxisomes, autophagic vacuoles, Golgi complexes, smooth endoplasmic reticulum or glycogen, and no significant change in the surface density of granular endoplasmic cisternae. The present investigation indicates that in the maternal hepatocyte certain cytoplasmic components are quantitatively changed by ethanol, whereas the volume and surface densities of identitical components in the fetal hepatocyte are unaffected. The significance of these results is discussed.

ISSN:1422-6405    

DOI:10.1159/000146451

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Morphological aspects of the myocardium in dogs with experimentally induced jaundice were assessed ultrastructurally. Obstructive jaundice was produced by chronic bile-duct ligation and by choledochocaval anastomosis. The left ventricular myocardium and the papillary muscle were used. Statistical analysis of sarcomere length and of mitochondrial density showed no significant differences between jaundiced and sham-operated dogs. Qualitative evaluation of the mitochondria, the intercalated disc and other sarcoplasmic constituents revealed no damage to the jaundiced dogs.

ISSN:1422-6405    

DOI:10.1159/000146452

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

We have studied the arrangement of the pectineal ligament or its equivalent, the uveal trabecula, in herbivores, carnivores, primates and humans. From our investigations, the pectineal ligament, the uveal trabecula and the so-called processes of the iris form a morphological unit that is made up of the tendinous fibres of the longitudinal portion of the ciliary muscle, that are inserted into the periphery of Descemet’s membrane and send out ahead prolongations that extend to the anterior face of the iris. The so-called processes of the iris cannot be considered as independent structures since they represent the innermost fibres of the trabecular or uveal meshwork; in some species these have a thicker appearance, an arrangement that can occasionally be found in the human eye.

ISSN:1422-6405    

DOI:10.1159/000146453

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Studies were performed onWistar strain rats aged 1–720 days. Immunocytochemical reactions were used to detect calcitonin, somatostatin, calcitonin gene-related peptide (CGRP), cholecystokinin, serotonin, neuron-specific enolase (NSE), secretory protein-I, chromogranin and Ca-binding protein. In the parafollicular cells of the rat, the presence of calcitonin, somatostatin, CGRP, NSE and secretory protein-I could be demonstrated. The number of parafollicular cells increased with the age of animals, and the increase was particularly pronounced in the early postnatal period and after the first year of age. The number of somatostatin-immunoreactive cells decreased after birth and increased again after the first year of age. The number of calcitonin-immunoreactive cells increased in the early postnatal period independently of the increase in parafollicular cell number, forming frequently tumor-like outgrowths in 2-year-old animals. A small proportion of these outgrowths contained no calcitonin even if they did contain somatostatin, CGRP and NSE immunoreactivity. Evident changes in immunoreactivity in the first days after birth may reflect the sudden change in environment and may be associated with growth and differentiation. In any period of life, CGRP- and NSE-immunoreactive cells have constituted the most numerous groups and, therefore, the respective antigens seem to represent the most suitable markers of parafollicular cells in the ra

ISSN:1422-6405    

DOI:10.1159/000146492

出版商:S. Karger AG    

年代:1987

数据来源: Karger