摘要:

The influence of thyroid deficiency and the administration of thyroxine on pituitary-testicular function were studied in male albino rats from weaning age (22 days old) up to 82 days of age. The results showed that the hyperthyroid state induced by a daily injection of 2.5 or 5 µg L-thyroxine resulted in acceleration of growth, a comparative increase in size and number of spermatogenic and interstitial cells, an increase in the STH cells, particularly at the earlier age (42 days old), and in a decrease in the number and size of TSH cells. Gonadotrophic FSH and LH and prolactin cells exhibited an increase in their granular content. The hypothyroid state induced by thyroidectomy or thiourea feeding, at the levels of 0.1 and 0.2%, resulted in the depression of growth rate, destructive changes of the spermatogenic and interstitial cells and also in the lumen of the seminiferous tubules. A decrease in the STH, gonadotrophic FSH and LH and prolactin cells and hypertrophy of TSH cells accompanied by degranulation were also observed

ISSN:1422-6405    

DOI:10.1159/000144788

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Comparative architectonic studies have resulted in a classification of the amygdaloid complex which differs somewhat from the commonly used classification (first proposed by Humphrey, 1936) by separating the cortical amygdaloid nucleus from the centromedial group and assigning it to the basolateral group, which then forms a cortico-basolateral group. The size changes of these groups and of the nucleus of the lateral olfactory tract (belonging to the centromedial group) and the large-celled part of the basal nucleus (belonging to the cortico-basolateral group) have been investigated in representatives of an ascending primate scale. In all structural complexes investigated so far, the small-celled part of the cortico-basolateral group is the most progressive. In descending order of progression there follow: the cortico-basolateral group as a whole, the amygdala as a whole, and the large-celled basal nucleus. No clear changes were found in the centromedial group as a whole, whereas the size of the nucleus of the lateral olfactory tract, which represents a small component of this latter group, shows a strong reduction. These differences in the developmental trends point to increasing or decreasing capacities of the functional (limbic and olfactory) systems, to which these structures are related.

ISSN:1422-6405    

DOI:10.1159/000144789

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Having applied the picric acid-bromphenol blue (BPB) and the phosphomolybdic acid-benzidine (PMA-B) methods – the first method detecting the total histone content, the second one only free histones – we have found that cell nuclei of the rat embryos permanently contain histones, nevertheless, in such a pattern that the free histone appears only at a well-defined stage of the embryogenesis. Strong PMA-B reaction is observable in the nuclei of some mesenchymal cells and in the reorganizing somites’ cell nuclei of the 13-day-old embryo as well as in the hemopoietic elements of the 15- and 17-day old embryos’ liver. Within nuclei of the red blood cells of the 13-day-old embryo an extremely intense reaction is seen which then disappears till the 15th day, while the BPB reaction shows a gradual intensification up to the neonatal age. The experiments support the former model of one of the authors for a histone-nonhistone control of onto

ISSN:1422-6405    

DOI:10.1159/000144790

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

(1) The investigation yielded several general growth principles, i.e., types of growth occurring rather frequently: (a) allometric growth, (b) a non-changing growth rate, persisting when the growth rate changes in the majority of tissues, (c) a growth rate equal to that of the whole embryo, (d) absence of growth and (e) jumps, i.e., changes in the volume or surface of organs completed within about half a day or less and probably due to changes in the cell volume or surface area; these histological changes tend to start simultaneously with the changes in growth rate. (2) Growth constants tend to have a value of about 2.0 in the prenatal period, as in the postnatal period. During development, however, their value increases slightly but significantly.(3)Further arguments are given for the mitosis-regulating model described in Part III.(4) The mitosis-regulating model combined with the general growth principles derived here and in earlier parts of this report constitute a comprehensive model for the genetic regulation of the growth process.

ISSN:1422-6405    

DOI:10.1159/000144791

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In this work, the authors studied the morphology of the axillary and mediastinal lymph nodes and their efferent branches in the white rat (Rattus norvegicus). The main characteristics observed were: The presence of two groups of axillary lymph nodes, one in the lateral and the other in the medial portion, and the presence of two groups of mediastinal lymph nodes, one being ventro-lateral and the other dorsoventral relating to cranial precava veins. Usually, in both sides, there is a lymphatic plexus dorsally to the jugulosubclavian angle, formed by reunion of internal jugular and subclavian trunks and the thoracic duct (to the left) or the right lymphatic trunk (to the right). From this plexus, one or two branches run off and flow into the venous jugulosubclavian angle. The subclavian trunk begins in the medial axillar lymph nodes and joins to the lymphatic plexus at the internal jugular trunk or at the thoracic duct or yet at the right lymphatic trunk according to the site, and finally it may link itself directly to the venous system. The mediastinal lymph nodes at the right side send branches forming the right lymphatic trunk and branches adhering to the lymphatic plexus; the left lymph nodes join to the plexus or the thoracic duct.

ISSN:1422-6405    

DOI:10.1159/000144792

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Columnar epithelium in Suncus murinus is secretory and the secretory product is rich in proteins and polysaccharides; it is devoid of lipids. The secretion is discharged into the lumen by a process of blebbing from the acinar tips of the columnar cells. The basal cells only replace the worn-out columnar cells.

ISSN:1422-6405    

DOI:10.1159/000144793

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The human aortic valve is examined histologically by light, transmission electron and scanning electron microscopy. The observations show that the valve leaflets are multi-laminated structures, whose laminae do not have very distinct boundaries. Through the whole thickness of the leaflets, the load-bearing collagenous fibers are preferentially oriented in the transverse direction. Elastin networks are found only in the ventricular area. The leaflets attach themselves to the ventricular musculature through very dense collagenous meshworks known as the aortic ring. The whole structure is very efficient for its function of sustaining large pressures when closed and opening under minimal pressure gradients in systole.

ISSN:1422-6405    

DOI:10.1159/000144794

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A quantitative method was used to establish the sexual dimorphism of bone robusticity in 10 domesticated strains of rats and in wild rats. Sexual dimorphism had its highest frequency in the pelvis, followed by the ulna, the skull, and the femur and tibia. Humerus and tail showed the lowest frequency of such sexual dimorphism. This distribution in an unspecialized mammal such as the rat, in which selective pressures are at their minimum because of the factor of domestication, can serve as a baseline for comparison with taxa in which selective forces are more strongly active.

ISSN:1422-6405    

DOI:10.1159/000144795

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Mouse gallbladder was fixed by perfusion or immersion in glutaraldehyde and/or osmium tetroxide for electron microscopy. Besides usual columnar epithelial cells there were infrequent tuft cells in the epithelium. The cells rested on the basal lamina and extended to the gallbladder lumen. The microvilli on the apical cell surface were tall and thick and there was a rich network of microfilaments radiating from the core of the microvilli to the apical and juxta-nuclear cytoplasm. Among the bundles of microfilaments there were vertically oriented microtubules in the apical cytoplasm. Although the function of the tuft cells in the gallbladder epithelium remains unknown, it is proposed that their unique morphology may reflect a specialized resorptive function involving motility of microvilli and other cell organelles.

ISSN:1422-6405    

DOI:10.1159/000144796

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In view of these anatomical findings, it is suggested that the electron-dense microvilli may be undergoing degeneration.

ISSN:1422-6405    

DOI:10.1159/000144797

出版商:S. Karger AG    

年代:1977

数据来源: Karger