摘要:

The fine structure of the prostate gland of the guinea pig was studied by electron microscopy. The lateral lobe was characterized by tall columnar epithelium which formed various degrees of foldings. The epithelial cells had well developed granular endoplasmic reticulum (GER). The cisternae were closely packed and often arranged in concentric configuration in the basal cytoplasm. The apical cytoplasm was characterized by a large Golgi and prominent secretory granules. The luminal border typically contained microvilli. Fusion of the secretory granules with the luminal membrane were observed. The secretion in this lobe is believed to be triggered by a merocrine mechanism. The glandular cells of the dorsal prostate were characterized by well-developed and dilated GER. Most cells had no secretory granules and the luminal surface was endowed with microvilli. It is believed that in these cells the secretion is stored in the cisternae and may be discharged directly into the lumen. A small number of cells in the dorsal prostate showed large dense secretory granules in the apical region. Secretion in this group of cells, as in the cells of the lateral prostate, is believed to be produced by a merocrine mechanism. The coagulating gland on the other hand, had sparser GER and less dilated cisternae. The cells contained no secretory granules and usually had a small Golgi. Apical blebs were commonly found in these cells. Apical blebs have been observed to pinch off from the apical cytoplasm and to release the small sacs of secretory material into the lumen. This is an apocrine mechanism of secretion.

ISSN:1422-6405    

DOI:10.1159/000145396

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Using histochemical methods, evidence of increased protein synthesis was observed in microvessels (diameter < 100 µm) from dog hearts which had been sympathectomized 2 weeks earlier when compared to controls. Such evidence consisted of increased staining intensity for the enzyme glucose-6-phosphate dehydrogenase and for the nucleic acids RNA and DNA. Increases in reaction intensities were noted in approximately 30% of the microvessels examined from the sympathectomized hearts, and may imply a vascular proliferation in these hearts. However, since no increase in capillary density was observed in sympathectomized hearts, a vascular proliferation, if it occurred, may have been involved in development of the coronary collateral circulation. These data support previous results indicating that collateral resistances are reduced following chronic cardiac sympathectomy while resistance of the coronary vascular bed itself is not altered

ISSN:1422-6405    

DOI:10.1159/000145397

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

A circular calvariectomy procedure was performed on 24 New Zealand white rabbits at 6 weeks of age. In 12 animals, the continuity of the dura mater was interrupted. The remaining animals served as controls. The animals were sacrificed at intervals to document the regenerative potential of the altered dural tissues. The results of this experiment show that bone deposition leading to calvarial redevelopment is directly dependent upon the presence of the dura mater. In addition, the rate of deposition is apparently affected by dural continuity, animal age, and localized differences in the thickness of the dural layers. The redevelopment and patency of the cranial sutures are strongly influenced by alterations in the continuity of the dura mater.

ISSN:1422-6405    

DOI:10.1159/000145398

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

In order to study the occurence of swollen and disrupted mitochondria in tissue preserved for electron microscopy by ordinary fixation methods, liver tissue from miniature pig fetuses was immersion-fixed in fixatives with various types and concentrations of fixing agents and vehicles. Also commercial and purified products have been tested, different fixation times and temperatures as well as the consequences of a short rinsing in buffer solutions prior to fixation. Furthermore, the significance of delayed fixation (autolysis) was studied. It was found that swollen and disrupted mitochondria occur predominantly in liver cells exposed to low concentrations of glutaraldehyde. It is shown that this phenomenon is a result of a specific effect of glutaraldehyde on the mitochondrial membranes. It is not accompanied by parallel changes of other organelles or nuclei, and it is not provoked by other fixing agents, vehicles or by delayed fixation (autolysis).

ISSN:1422-6405    

DOI:10.1159/000145399

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

A quantitative ultrastructural morphometric study was performed on the prolactin (PRL) cells of lactating mice, at different times in a circadian period. The results showed significant time fluctuations in the percentages of cytoplasmic volume occupied by several organelles. The endoplasmic reticulum appeared more developed during the dark period, indicating a higher synthesis of secretory material in this phase. The Golgi complex, including an increased number of immature granules, was found remarkably enlarged during the light period. Moreover, the release of PRL would be increased during the dark phase, as judged by the diminution of the secretory granules and the higher degree of emiocytotic activity. The present morphometric approach in the detection of circadian variations of PRL secretion in lactating mice is emphasized.

ISSN:1422-6405    

DOI:10.1159/000145400

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Increasing doses of propranolol were injected intraperitoneally to four series of adult male rats in order to study the effect of this β-blocking agent on various organs (testis, epididymis, prostate and seminal vesicle) and endocrine glands (adrenals, pancreas, thyroid, pituitary). Histological damage was observed only in testes: i.e., necrosis and desquamation of germinal cells in the seminiferous tubules associated with light arterial vasoconstriction. Pelviperitoneal fibrosis was observed as well. These lesions seem to be of pharmacological vascular origin and appear to occur in combination with an elective toxic effect of propranolol on the germinal cells

ISSN:1422-6405    

DOI:10.1159/000145401

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The vital staining mechanism of alizarin red S (ARS) was investigated. The total calcium content of rat blood was determined after intraperitoneal and intracardial administration of acidic, neutralized and calcium-supplemented ARS. The administration of ARS causes, irrespective of chemical state, a remarkable decrease in blood volume and a significant decrease in the serum/blood ratio. The total calcium content of rat serum was noticeably increased, more in the case of intracardial than in the case of intraperitoneal administration. The calcium values determined in this work were the sums of free and bound calcium. The increase in calcium content even in those cases where ARS was administered without calcium indicates a physiological ability to keep the concentration of free calcium constant in the blood. The highest calcium values were found when calcium-supplemented ARS was administrated. The physiological activity, however, seems to be higher with acidic ARS, which also contributed to the vital staining effect on rat skull. The best staining with least inconvenience was achieved using neutralized ARS for in vivo staining.

ISSN:1422-6405    

DOI:10.1159/000145402

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The ultrastructural relationship between the receptor nerve fiber and the surrounding lamellae in Krause end-bulbs was discussed. Many sites of specialized junctions of symmetrical or asymmetrical type along the receptor nerve fiber and the surrounding lamellae were found. In addition, in close vicinity to them, spine-like digitations of the receptor nerve fiber, filled mainly with small clear vesicles, were observed. Mitochondrion-like cholinesterase-positive structures bulging in some cytoplasmic lamellae were also found. It is suggested that a functional link might exist between the specialized junctions, digitations and mitochondrion-like structures in the transformation of external mechanical stimuli into nerve impulses.

ISSN:1422-6405    

DOI:10.1159/000145403

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The capillary network of the enamel organ of the continuously growing mandibular incisor of the rat is supplied by a series of arteries which, after penetrating the bone, are disposed in a row in the periodontium along the tooth and linked together by anastomoses. The branches from these arteries are subjected to adaptive changes consistent with a forward movement of the capillaries in relation to the arteries. The mechanism which renders this movement possible appears to be the following: Each artery in the row supplies a section of the passing plexus by coupling and uncoupling short-lived arterioles, which go through a cycle of proliferation, elongation and degeneration. Proliferation takes place at the posterior end of the section, where new arterioles replace discarded arterioles from the preceding artery. By growing in length, the arterioles keep pace with the migrating capillary network. When the capillaries are within reach of the next artery, the arterioles disconnect. Thereafter they become obliterated and die in the intermediate zone of the periodontium, to which they have been gradually displaced by proliferation of the inner-tooth-related layer of the periodontal connective tissue.

ISSN:1422-6405    

DOI:10.1159/000145404

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000145405

出版商:S. Karger AG    

年代:1981

数据来源: Karger