摘要:

An attempt is made to describe the vascular architecture of the cortex employing a stereological method. Brains perfused with India ink were sectioned in frontal, sagittal and tangential levels. The course of the vessels was described as a spatial vector from the center to the penetration point of the globe of radius 1. In order to present a two-dimensional image, we projected the penetration point together with the longitudinal and horizontal meridians of the globe in an orthograde fashion into the level of the image. The frontal and sagittal sections were projected in an equatorial image, the tangential level was projected to an axis. Direct observations and stereological imaging demonstrated that, in lamina 4, there is a relatively constant hexagonal vascular net with branching angles of 60° at an edge length of 50–60 µ

ISSN:1422-6405    

DOI:10.1159/000145038

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Out of 49 serially studied juxtaglomerular apparatuses, 6 typical variants from two normal human kidneys were reconstructed graphically. The agranular Goormaghtigh cells filled the entire space between the macula densa, the afferent and the efferent arterioles and the glomerular mesangium. The Goormaghtigh cells were always in direct contact with all the other structures. They also invariably continued into the glomerular mesangium. The distal tubule regularly showed widening in the macula densa segment and, at this level, there was considerable variation in the shape of the distal tubule. Direct contact between the macula densa and the hilar arterioles was not always present, the area of contact was usually greater with the afferent than with the efferent arteriole.

ISSN:1422-6405    

DOI:10.1159/000145039

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Closure between the secondary palate and the primary palate and between the former and the nasal septum was studied in the Syrian golden hamster at light- and electron-microscopic level. Sequential changes in the epithelia before, during and after the closure of the primary and the secondary palate were described. A characteristic epithelial thickening was observed prior to epithelial fusion between the nasal septum and the secondary palatal shelf. Fusion of the opposing epithelia was characterized by formation of desmosomes. An unilateral or bilateral empty space was observed on each side of the epithelial seam, and it was suggested that this may represent the incisive foramen in the adult.

ISSN:1422-6405    

DOI:10.1159/000145040

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Embryologic studies have shown that the ganglions of the peripheral nervous system are formed by the neuroblasts from the central nervous system. The histotopography of the neurons and their segmental communications with the central nervous system are established experimentally (segmental section of the ventral roots and resection of the spinal nodes: 100 experiments). It is proved that the neurons, which communicate with the definite segment of the spinal cord, are diffusely distributed in the ganglion mass.

ISSN:1422-6405    

DOI:10.1159/000145041

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

A study was made to determine the behavior and fate of transplanted reptilian teeth with a pleurodont type of attachment. The purpose was to compare this attachment with the behavior of other types of attachments, when they are transplanted, and to determine which portions of the ankylosed tooth are controlled by intrinsic factors. 50 small green iguanas were used. Autologous transplants of both individual buds of a known stage of development and small blocks of the entire upper or lower jaw were placed in the gular region or anterior chamber of the eye. The transplants and the jaws were examined at intervals from 0 to 180 days. Tooth buds transplanted with or without the jaw were capable of growth to normal size and shape. New bud formation also began after transplant acceptance, and buds were more protected from epithelial injury than previously reported amphibian tooth transplants. The ankylosed adult tooth began the process of shedding almost immediately. While lack of normal environment and lack of underlying bone did not prevent formation of a normal root shaft with dentin, there was little evidence of induction of the ‘bone of attachment’ and underlying jaw bone by the growing buds. The root shaft size and shape were, therefore, intrinsic features of the pleurodont to

ISSN:1422-6405    

DOI:10.1159/000145042

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Electron-microscopic investigations on the human adrenal cortex have been carried out in order to elucidate ultrastructural differences in the various zones. These studies indicate that certain differences in the ultrastructure of the mitochondria may be particularly useful as criteria to differentiate the three cortical zones. In this regard, the appearance of two types of mitochondria in the zona glomerulosa as well as in the zona fasciculata is of obvious interest. The probability of a relationship between the activity of the different cortical zones and the predominant presence of one form of mitochondria has been suggested. In addition, ultrastructural transformations following stress situations as well as problems dealing with the so-called ‘dark and light cells’ and the basal membrane are discus

ISSN:1422-6405    

DOI:10.1159/000145043

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Masticatory habit is a major factor determining the morphology of the craniofacial skeleton. The craniofacial skeleton essentially comprises a series of bony stress-bearing bridges forming a structural framework. The structural framework of the skull of dog has been described as a rigid trestle-like structure; it can be illustrated by mechanically removing nonresistant areas of bone. It is then found that a framework is produced which is partially rigid (cranium) and partly flexible (rostrum). It is postulated that the flexibility of the rostrum acts to absorb shock and it is suggested that the primate postorbital bar is developed in response to craniofacial morphology which increases compressive bite forces.

ISSN:1422-6405    

DOI:10.1159/000145044

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Various histochemical and histological techniques were used to study the melanin and dopa-positive cell.distribution in the skin of some tropical and temperate breeds of cattle in Nigeria. Melanin pigments were concentrated in the basal and lower spinous layers of the epidermis and in the hair cortex, follicle sheaths and papillae of the various breeds. In the White Fulani and N’Dama breeds, melanin pigments were however found in all layers of the epidermis. Dopa-positive cells (melanocytes) were observed in the epidermis, dermis and hair follicles; the distribution pattern varied among breeds, being copiously disposed in the basal epidermis and papillary dermis in the White Fulani and Muturu and, except in areas of thick epidermal ridges, scanty in the epidermis and dermis of the Friesian and N’Dama. Mast cell distribution pattern in the various breeds was similar to that of the dopa-positive cells. Peroxidase-positive cells were present in the basal epidermis and upper dermis of the Muturu, widespread in the subepidermal layer of the N’Dama and very scanty in the dermis of the White Fulani and Friesian. Acid phosphatase activity was intense in the granular layer of the Muturu and N’Dama breeds and also in the papillary dermis and hair follicles, whereas alkaline phosphatase-positive dendritic cells, and ‘clear’ cells were also observed in the basal and uppe

ISSN:1422-6405    

DOI:10.1159/000145045

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Limb buds of 11-day-old mouse embryos were cultured. On day 5,0.1 ml colchicine was added for 3, 6, 12 or 24 h in vitro. 3 or 6 h after application of colchicine, electron-dense granula appear to an increasing extent. These granula can be interpreted as collagen-containing secretion granula and as an indication of a secretion inhibition. The peripheral localization of the granula groups speaks for an effect on the actual discharge of the secretion after having passed the Golgi apparatus. Additional effects of colchicine are fragmentation of the Golgi apparatus and an increased occurrence of bundles of fine filaments. Since only few microtubuli occur in the periphery of the chondroblasts and recent studies indicate an influence of colchicine not only on the microtubule system, a site of action at the functional unity ‘cell membrane-microfîlaments’ is discussed. 12 or 24 h after colchicine application, the contents of the congested secretion granula change. The occurrence of cross-striated structures indicates an activity of procollagen peptidase in the granula in the case of secretion inhibition. In addition, cytolysosomes (autophagic vacuoles) develop. The occurrence of polymorphism of the granula contents under these conditions is attributed to an effect of lysosomal enz

ISSN:1422-6405    

DOI:10.1159/000145046

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

β-Histine-HCl has been shown to be effective in modifying the size of developing myocardial infarcts. In the present study the hypothesis that β-hιstine increases the flow of blood through collateral channels and thus supplies blood to ligated areas of the myocardium was investigated in the dog. The methods used were measurement of retrograde coronary blood flow and angiography after coronary artery ligation. β-Histine administration for 6 h increased retrograde blood flow 68.2–91.0% over controls. Coronary angiography demonstrated the existence of collateral channels 200–400 µm in diameter within the myocardium after ligation and 4 h of β-histine admin

ISSN:1422-6405    

DOI:10.1159/000145047

出版商:S. Karger AG    

年代:1979

数据来源: Karger