ISSN:1422-6405    

DOI:10.1159/000144875

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The use of an experimental procedure based upon progressive postoperative delays allowed the quantification of the effects of enucleation performed at the ages of 2, 8 and 20 days, corresponding to key stages of the postnatal maturation of the optic nerve, namely premyelination, myelination and postmyelination. Two main events were noteworthy regarding cell reactivity. The higher the age of the animals at operation, the lower was the proliferation, and the larger was the time lapse between operation and the peak of proliferation. The interferences between reaction gliosis and myelination gliosis depended upon the developmental stage of the optic nerve. This reflects a progressive loss of plasticity.

ISSN:1422-6405    

DOI:10.1159/000144876

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The development of colon mucosa during postnatal growth was analyzed in male BD IX rats using histological and radioautographic methods. Newborn animals already exhibited clearly recognizable crypts of Lieberkühn. DNA synthesis activity predominated in the lower two thirds of those crypts, as it constantly did during subsequent growth and in adult colons. The height of crypts at birth was already half the adult size. There was, in contrast, a dramatic increase in their number (more than 1,000% from birth to the 10th week, as observed on transverse sections). The mechanism by which new glands derive from the mucosal epithelium implies a longitudinal fission of preexisting glands

ISSN:1422-6405    

DOI:10.1159/000144877

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

For investigation of the vascular supply of the os scaphoideum we produced post mortem injection specimens of hands with latex milk. The extraosseous vessels were prepared macroscopicaliy and microscopically. The intraosseous vascular distribution was represented by cleared specimens (Spalteholz technique). A branch of the arteria radialis or of the ramus dorsal is arteriae radialis enters the dorsal face in the middle and distal third by several foramina nutricia. This artery effects the blood supply almost completely. Other vessels entering the navi-cular bone are small calibrated and only sometimes demonstrable. The proximal third of the scaphoideum shows no artery entrance.

ISSN:1422-6405    

DOI:10.1159/000144878

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

In this study the attempt was made to classify the reticulum cells of the bone marrow on the basis of electron-microscopic findings. The basis of the differentiation was the ability of the cells to phagocytize substances or not. For two cell types the intracytoplasmic filaments were used as distinctive marks. The following classification resulted: (a) phagocytic reticulum cells, (b) undifFerentiated reticulum cells, (c) fibrous reticulum cells of type I, which contain filaments of 4–8 nm diameter and are located near the blood sinus of the bone marrow, (d) fibrous reticulum cells of type II, which contain intracytoplasmic filaments of 10 nm diameter; since these cells contain neutral fat bodies, the possibility of a reversible conversion to fat cells has to be assumed and (e) fibroblasts, cells which synthesize the substance of the extracellular space. A connexion of reticulum cells to haematopoietic functions or to stem cell functions could not be foun

ISSN:1422-6405    

DOI:10.1159/000144879

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The drug malononitrile dimer (1,1,3-tricyano-2-amino-1-propene) was administered intraperitoneally to groups of mice at 20 mg/kg body weight, either as a single injection or as chronic 2-month injections. To study the effect of malononitrile dimer on RNA synthesis in the brain, it was necessary to choose a precursor that would pass the blood-brain barrier. Animals were injected with 14C-formate, then sacrificed 1 h later. RNA synthesis in the brain, liver and kidney of the drug-injected and control animals was determined by the amount of 14C-formate incorporated into newly synthesized RNA. A new method involving the comparison of RNase-extracted with non-extracted slides is described for determining the proportion of 14C-formate incorporated into RNA radioautographically. The results show that RNA synthesis was significantly increased as a result of both single and chronic malononitrile dimer injections in all tissues studied. In most cases, malononitrile dimer nearly doubled the percentage of 14C-formate incorporated into newly synthesized RNA. The effect of the chronic injections was most pronounced in the brain. The mechanism of malononitrile action on RNA synthesis as mediated by thyroxine is discussed.

ISSN:1422-6405    

DOI:10.1159/000144880

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Adrenal medulla and carotid body of cats are studied with acrylic aldehyde-dichromate and glutaraldehyde-dichromate methods for catecholamines. The frequency of dark vesicles and the mean diameter of the cores obtained by these specific methods are compared with those found by the standard glutaraldehyde-osmíum method in normal and reserpine-treated animals. In the samples of normal organs fixed with aldehyde-dichromate methods, the number of dark-cored vesicles is significantly higher than in the controls. On the contrary, in the adrenal gland of reserpine-treated specimens the specific methods demonstrate reductions in the frequency of dark vesicles that can be semiquantitatively compared with the known diminution in the content of catecholamines produced by the drug. In the carotid body it was not found a so strict relation, nevertheless the specific methods give a consistently lower frequency of dark vesicles in reserpine-treated than in control animals. It is suggested that the discrepancy between standard and specific methods in the carotid body is due to substances existent in the dark cores contrasted by the former procedure but not by the latter. The constancy of the mean diameter of the cores even in glands that have lost 93% of their granules confirms the suggestion of an all-or-nothing exocytotic mechanism of discharge of the secretory vesicles. The inverse relation shown between the frequency of dark and clear vesicles indicates that membranes emerge in the cytoplasm after exocytosis as clear vesicles

ISSN:1422-6405    

DOI:10.1159/000144881

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The structure of the nerve fibres in the chronically isolated cat ileum was studied by fluorescence and electron microscopy after imipramine group compounds, parachloro-phenylalanine, and 5-hydroxytryptamine treatment. Following treatment with parachloro-phenylalanine and imipramine group compounds in the nerve fibres of the small intestine, specific granules were selectively decreased (p < 0.001) in number. In concordance with ultra-structural observations, a marked diminution of fluorescence intensity was demonstrable in the small intestine. In addition, the number of the granular vesicles was significantly increased following 5-hydroxytryptamine treatment, and yellow fluorescent neurones and processes were observed in the myenteric and submucous plexuses. On the basis of these observations, the serotoninergic nature of certain nerve fibres could be dernonstra e .

ISSN:1422-6405    

DOI:10.1159/000144882

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

The nucleolar changes in the dorsal root ganglion cells of the squirrel monkey, Saimiri sciureus, have been investigated by the use of histological and histochemical methods in the healthy neonates (born to mothers maintained on 25% protein diet during gestation) and young adults, and compared with those observed in the protein-malnourished neonates (born to mothers maintained on a 8% protein diet during gestation). Also studied were young adults maintained on a high protein diet (25% protein) as well as on a low protein diet (2% protein content) for a period of 15 weeks. Whereas in the healthy animals (neonates and young adults) only a few cells show nucleolar budding and finally their extrusion into the cytoplasm, the protein-malnourished animals show a significantly enhanced nucleolar activity in the form of increased size (3–4 times the original) and active budding either from one focal point or at several places on the body of the nucleolus. In the neurons which show chromatolytic changes, these extrusions migrate to the nuclear membrane, wherefrom they pass on to the cytoplasm through an evagination of the nuclear envelope. Such a migration appears to occur by a focal dissolution of the nuclear membrane. It appears that, under conditions of severe malnutrition and advanced chromatolytic changes in the neuronal cytoplasm, the nucleolar material provides a compensatory mechanism for the increased cytoplasmic catabolism and loss of ribonucleoprotein material in order to facilitate additional protein synthesis for cell surviva

ISSN:1422-6405    

DOI:10.1159/000144883

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

In the nervous part of the hypophysis, significant decrease in the quantity of neurosecretion, hypertrophy, and frequent findings of mitosis of adenopituicytes occur under the influence of noise and vibrations. In chronic audiovibratory stress, the phenomenon of hyperplasia of adenopituicytes and intracytoplasmic presence of structural elements of neurosecretory fibres in disintegration are noticeable. Heterogeneity of neurosecretory fibres is characteristically manifested in the presence of dilated Herring bodies with preserved structure, occurrence of nerve swellings very variable in structure, with numerous polymorphous inclusions and autolytic bodies, or with large vacuoles, few secretory granules and few mitochondria. There are some endings of neurosecretory fibres with many clear microvesicles and few granules, as well as the endings abounding only in clear microvesicles, particularly in pericapillary spaces. The results obtained point to strong stress-inducing effects of noise and vibrations upon the nervous part of the hypophysis.

ISSN:1422-6405    

DOI:10.1159/000144884

出版商:S. Karger AG    

年代:1978

数据来源: Karger