摘要:

Postnatal injections of a single dose of testosterone propionate or estradiol benzoate to newborn female hamsters produce a precocious vaginal opening at 5 days of age. Vaginal postnatal development, histologically, has shown that in testosterone-propionate-injected animals sinusal vagina is absent. The Müllerian vagina presented a stimulated epithelium at early ages. After 40 days, the Müllerian epithelium was stratified keratinized, with zones of stratified cuboidal epithelium. In estradiol-benzoate-treated animals, the Müllerian epithelium rapidly changes to stratified keratinized epithelium (10 days), with zones of stratified cuboidal after 20 days of life. The sinusal epithelium was stratified squamous at 10 days, and after 40 days changes to stratified keratinized epithelium were seen. Probably, early changes are due to a direct effect of steroid action. Later effects are due to ovarian secretion. Histologically, no significant changes were observed in the preputial and urethral glands. The clitoris showed malformatio

ISSN:1422-6405    

DOI:10.1159/000144755

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

We have made a histological study of the postnatal development of the clitoris, preputial glands, urethral glands and vagina of the golden hamster. The ‘phallic groove’ of the clitoris is closed at 10 days of life, then the urethra has a cuboidal stratified, a stratified squamous and a stratified keratinized epithelium. The preputial glands are composed of branched saccular glands. These glands develop, with few changes during their maturation period. Formation of the urethral glands begins at 5 days and the alveoli are fully developed at puberty. The hamster vagina has two origins; the upper part is Müllerian, the caudal part is sinusal. The wall of the Müllerian vagina has a cylindrical epithelium at birth, which becomes ‘double epithelium’ at puberty and thereafter changes cyclically in connection with the estrous cycle. The sinusal vagina is solid at birth, its lumen being formed in the first 10 days of life and its wall having a cuboidal stratified epithelium. At 15 days it becomes a stratified keratinized epithelium, which will later line the vaginal pouch. At the 5th day, an ectodermic invagination (stratified keratinized epithelium) is observed in the zone of the future introitus. At the time of vaginal opening this zone forms the dista

ISSN:1422-6405    

DOI:10.1159/000144756

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Timed pregnancies were obtained in Sprague-Dawley rats, and cardiac tissues from embryos of days 10, 11, 12, 13, 14 and from newborn rats were used for the cytochemical localization of ATPase activity utilizing a lead phosphate precipitation procedure. Following incubation with ATP as the substrate, granular deposits of reaction product are discernible on the cell membranes of the embryonic myocardium. There is a noticeable decrease in the intensity of reaction product as visualized in the electron micrographs from the 10th day of gestation to the 14th day. No granular reaction product is recognizable in myofibrils, mitochondria or other organelles in the cytoplasm. It appears that there is a selective deposition of the reaction product on the cell membranes or structures derived from it. The intense ATPase activity seen on 10th and 11th days seems to be correlated with the initial appearance of myofilaments and fibrils in the myocardial cells.

ISSN:1422-6405    

DOI:10.1159/000144757

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

On ten otter brains the appearance of the exterior and interior brain structures was studied. Viewed from above there are two forms of brain, a triangular and a longitudinal one. In the triangular form the gyri are sufficiently developed with a considerable number of transient gyri and in the !ongitudinal form the gyri are wider and separated by considerably deep sulci. The olfactory bulbs, the olfactory tract, the gyrus olfactorius medialis and the gyrus olfactorius lateralis are less pronounced in the triangular form than in the longitudinal one. In the triangular form of the brain all gyri, except for the gyrus sylvius, are vertically positioned. The brain stem is wider in the triangular form and narrower in the longitudinal one. On the medial aspect of the brain, the cingulate gyrus, on which transient gyri are apparent, is well marked. The cingulate gyrus is slightly wider than in the longitudinal form. Below the splenium corporis callosi there is the tuberculum gyri dentati to be found by a shallow sulcus which is separated from the gyrus corporis callosi. By scaling the brain matter from outside, the pes hippocampi is exhibited. In the longitudinal form it is more sloping and separated from the base of the brain by a thin layer of brain substance. In the triangular form of the brain the cerebellum is covered by the posterior portions of the hemisphere and in the longitudinal form projects rather backward. On the frontal sections of the cerebrum the subcortical grey masses are sufficiently developed.

ISSN:1422-6405    

DOI:10.1159/000144758

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Due to the fact that the literature in the last 20 years shows contradictory points of view regarding the morphology and relations among the nasal cartilages in man, gross, semi-macroscopic and light-microscopic surveys were carried out in 20 adult and fetal human noses. It was concluded that the septodorsal cartilage is made up of only one block. The attachment of the septodorsal cartilage to the nasal bones takes place from 2 to 5 mm in the inner aspect of the latter. The distal and fibrous portions of the lateral cartilage and the greater alar cartilages act as valves.

ISSN:1422-6405    

DOI:10.1159/000144759

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

An anatomical peculiarity of the first cervical vertebra is described: the retrotransverse groove (or canal) containing an anastomotic vein.

ISSN:1422-6405    

DOI:10.1159/000144760

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The baroreceptor endings of the sinus nerve extend into the region of the external media, to the media-adventitia border, and into the adventitia of the wall of the carotid sinus. The size of the receptors, tightly filled with mitochondria, varies between 600 and 5,700 nm in diameter. The endings are accompanied by densely structured Schwann’s cells, come into contact with the muscular-elastic system or are surrounded by the collagenous material of the vessel wall. This functional junction makes the reception of the tension in the vessel wall possible. Glycogen granules could be demonstrated in some axon endings. In kittens and older cats, numerous receptors were regularly found with various degrees of structural change: homogeneous and lamellar transformation of mitochondria, lamellar aggregates, lysis of axoplasm matrix, irregularities of tubules and vesicles. These modifications may be evaluated as the morphological expression of degeneration and regeneration processes. Physiological detrition is considered to be the cause for thi

ISSN:1422-6405    

DOI:10.1159/000144761

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The effect of alcohol was studied in the visual cells of the chick. Outer segment degenerations were the most conspicuous findings whereas the inner segments remained unaffected.

ISSN:1422-6405    

DOI:10.1159/000144762

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Cartilage differentiation in the upper limb bud of the white mouse (NMRI) begins in the humerus anlage on day 12 + 13 h p.c.; cartilage differentiation in the phalanges begins on day 13 + 3 h p.c. Morphologically, differentiation can be characterized as follows: (1) cell densifications with an increase in contact structures between the cells in the blastema centre; (2) development of a two-layered cell densification: a central cartilage zone and a peripheral zone (perichondrium), between precartilage and prospective muscle anlage; numerous mitoses appear in this peripheral zone; (3) appearance of filaments and PG granula in the intercellular space as well as massive appearance of rough endoplasmic reticulum in the cytoplasm and, (4) increased distance between the cells coupled with the loss of specific contact structures and substance increase in the intercellular space.

ISSN:1422-6405    

DOI:10.1159/000144763

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The neonate rats of 5 days postnatal age were exposed to low-level X-ray irradiation or were administered microquantities of N-ethyl-N-nitrosourea directly into the cerebellum. Following the initial phase of cell degeneration and phagocytosis of the debris, the surviving Purkinje cells showed recovery of their differentiation. During this stage some Purkinje cells were observed to undergo mitosis, and they were identified in light- and electron-microscopic preparations. The relationship between tetraploidy in the Purkinje cells during their postnatal differentiation and induction of mitosis in them by experimental means is discussed.

ISSN:1422-6405    

DOI:10.1159/000144764

出版商:S. Karger AG    

年代:1977

数据来源: Karger