摘要:

The effects of zinc and copper salts on the survival of the two species of freshwater fish, common carp,- Cyprinus carpio, and grass carp, Ctenopharyngodon idellus, were investigated. It was discovered that the levels of tolerance to the concentration of the metals were species-specific. Cyprinus carpio was found to be more susceptible to copper, whereas Ctenopharyngodon idellus was more susceptible to zinc. In general, copper was more toxic than zinc, as revealed by the survival times. The body and the gills of dead fish seemed to be covered by a veil-like film which looked like coagulated mucus and which was formed by the heavy-metal ions reacting with some constituents of the mucus secreted by the gill. The histopathological assessment of the gill and liver of Cyprinus carpio was also carried out. Particles were observed around the gills of the dead fish treated with zinc and copper salts, although no other major changes were found in the gill. Several histopathological changes were observed in the livers, including the presence of particles. The symptoms of the liver suggested that the internal injury was also an important feature of the intoxicants.

ISSN:1422-6405    

DOI:10.1159/000144869

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In the periosteum of newborn, 8-, 30- and 60-day-old albino rats, β-glucuronidase, β-galactosidase and succinate dehydrogenase were found. The enzymes of the investigated age groups show remarkable differences in reaction. β-Glucuronidase reacts distinctly in the cells of the cambium layer of 8- and 30-day-old animals. β-Galactosidase reacts very differently in the cell layers of the periosteum of albino rats in all age groups. The reaction of succinate dehydrogenase we found above all in the cambium cells, the preosteoblasts and the osteobla

ISSN:1422-6405    

DOI:10.1159/000144870

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

In neonatally estrogenized mice, uterine epithelial cells possessed a few microvilli on the fuzzy-appearing apical surface, regardless of the presence or the absence of estrogen. The cells showed well-developed rough endoplasmic reticulum and a large number of mitochondria, suggesting that the cells were actively functioning. At 13 months of age, the uterine epithelium of neonatally estrogenized mice was sometimes stratified and squamous. Spherical basal cells like those appearing in cancerous vagina in estrogen-treated mice made their appearance. These cells may have the capacity of autonomous proliferation.

ISSN:1422-6405    

DOI:10.1159/000144871

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

This work was undertaken to study the myelination and cholinesterase activity of the developing white matter of chick embryo spinal cord from the 6th day of incubation until hatching. Myelination of the white matter was always preceeded by the aggregation of neuroglial cells. The sequence of myelination in the cervical and thoracic segments was from before backwards, whereas in the lumbosacral segments it was from behind forewards. Myelination of the ventral column extended craniocaudally, whereas in the posterior column is extended caudocranially. True cholinesterase activity was encountered in the spinal white matter only before and during the process of myelination and was closely associated with the sites of neuroglial aggregations. No pseudocholinesterase activity could be seen in the white matter before myelination. However, during the period of active myelination, enzymatic activity was seen only at the sites of formed myelin and after myelination of all tracts; the whole white matter reacted positive for the enzyme. The significance of these findings is discussed.

ISSN:1422-6405    

DOI:10.1159/000144872

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The hypoglossal artery in a human fetus studied by post mortem angiography and microdissection is described. In contrast to the fetal form of the trigeminal artery which differs from the adult form by possessing branches supplying the pons and anastomotic branches to the cerebellar and internal auditory arteries, there were no major anatomical differences between the fetal and the adult form of the hypoglossal artery. The incompetence of the vertebral arteries in the presence of a hypoglossal artery is also emphasized.

ISSN:1422-6405    

DOI:10.1159/000144873

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000144874

出版商:S. Karger AG    

年代:1977

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000144858

出版商:S. Karger AG    

年代:1977

数据来源: Karger