摘要:

In young dogs movements of cranial bones at the sutura sagittalis and sutura coronalis have been shown. They correlate with arterial blood flow. The connective fiber arrangement in the sutura, which has been found earlier, can be explained as being related to these movements.

ISSN:1422-6405    

DOI:10.1159/000145785

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The number and size of myelinated axons in the L4 dorsal spinal root were determined in young rats and compared to those in the adult (older than 1 year) and in the old rats (older than 2 years). While the total number of myelinated axons was about the same at all ages, the average overall axon diameter showed a growth-related increase in adult animals, followed by a decrease reflecting senile atrophy in old rats. It is suggested that in aging laboratory rats the extent of axon shrinkage could account for the occurrence of secondary radicular demyelination.

ISSN:1422-6405    

DOI:10.1159/000145786

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

4 adult female virgin rabbits underwent bilateral oophorectomy. 4 weeks later methylmethacrylate corrosion vascular casts of their uterine tubes were prepared. Scanning electron microscopy of the acrylic casts revealed a decrease in the size and number of the large ampullary plical and fimbrial veins which are normally characteristic of these regions. This observation suggests that the reported tubal dysfunction which follows oophorectomy may have a vascular component.

ISSN:1422-6405    

DOI:10.1159/000145787

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The structure of the lower oesophageal sphincter (LOS) of the cat was investigated in comparison with that of the oesophagus. The following two main results were collected: (1) The muscularis mucosae of the lower oesophageal sphincter is much thicker than at oesophageal level (221 µm as compared with 17.8 µm on average). This thickening is particularly marked at the most prominent foldings of the mucosa. (2) Numerous annulo-spiral thin elastic fibres were found, in the circular layer of the LOS. These structures will coil spirally around muscular bundles and then wrap themselves around adjacent bundles so that they present an oblique orientation with regard to muscular fibres. Therefore it is concluded that in this species, the LOS is morphologically differentiated from the oesophagu

ISSN:1422-6405    

DOI:10.1159/000145788

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Small electrolytic lesions were placed on the head of the caudate nucleus of kittens between 8 and 21 days postnatally and in adult cats. Coronal sections of the whole brain were studied under the light microscope with the Fink and Heimer staining method. Degenerating axon terminals could be recognized after a survival period of 30 h for kittens and 8 days for adults, as dark spots and broken fibers. The results indicate extensive degenerative lesions at both diencephalic and brain stem levels. In general the degenerative lesions were denser in kittens when compared with adult animals. The results of this study suggest that the caudate nucleus of immature animals could be more sensitive to the lesions occurring during the time of early synaptogenesis. Moreover, the caudate nucleus could be an important point of convergence of descending pathways exerting a diffuse modulatory action upon several brain structures related to movement.

ISSN:1422-6405    

DOI:10.1159/000145789

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Development of the otic anlage was studied by means of scanning electron microscopy in exencephalic loop-tail (Lp/Lp)embryos and in their normal (+/+; Lp/+)littermates at 8.5–9.5 days of gestation. In the abnormal embryos, the cells of the otic pit lack the rounded prominent surfaces and dense arrangement of microvilli which characterize the normal otic pit, and the overall configuration of the otic anlage is also distorted. The relatively early manifestation of abnormalities in the otic anlage of this mutant suggests that the defective neural tube may exert an influence as early as the otic placode stage, or that a common factor may simultaneously affect both otic and neural tube development in this mutan

ISSN:1422-6405    

DOI:10.1159/000145790

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The volume of interphasic and mitotic pancreatic acinar cells of 20-day-old rats was estimated by analysis of drawings from Araldite-embedded serial thick sections. Assuming the average interphase cell volume to be 100%, the volume of prophase cells was 145%, reaching a volume of 180% during anaphase. Postmitotic acinar cell volume was 74%.

ISSN:1422-6405    

DOI:10.1159/000145791

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The ultrastructure of splenic cells and frequency of cell types were examined in fetal rats during progesterone-induced (P23, 24, 25) and surgically-induced (S23, 24, 25) prolonged gestation, and compared to term (T) fetuses and newborn animals (N1 N2, N3). Statistical analysis revealed an increase in numbers of erythroblasts and a decrease in numbers of neutrophils in post-term fetuses distinct from that seen in term and newborn animals. However, there were also significant differences between the post-term groups: the frequency of erythrocytes and total number of cells were higher in the drug-treated group, despite similar splenic weights in the two. The results are interpreted as a response by the spleen (increased erythropoiesis) to fetal hypoxia, which is known to exist during prolonged gestation.

ISSN:1422-6405    

DOI:10.1159/000145792

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Scanning and transmission electron microscopic studies, together with histochemical investigations, were conducted on rat and porcine intra-arterial cushions from the uterine vascular bed. In the rat, the fine structure of these cushions closely resembled that previously described in the rat kidney. The cushions were composed of modified smooth muscle, circularly disposed in an incomplete, raised band surrounding the entrance to arterial branches. These muscle cells projected as attenuated processes throughout the loosely organized, PAS-positive stroma, and established close contact with thin endothelial extensions projecting from the base of the surface endothelial cells. Scanning electron microscopic observations of furrows on the endothelial surface gave rise to the suggestion that such contacts might mediate muscular control of endothelial surface topology. In similar cushions from the pig uterine artery, the smooth muscle of the cushions was much more compactly organized, and was disposed radially, rather than circumferentially, within the cushion structure. The enzyme histochemical profile of porcine cushions did not differ appreciably from that of normal vascular smooth muscle and endothelium, suggesting the maintenance of a metabolic similarity with adjacent tissues. These studies clarify the fine-structural basis for recently reported contraction and relaxation of uterine artery cushions during ischemia and perfusion of the rat uterine vascular bed, and thus, for their functional role in the regulation of uterine vascular flow.

ISSN:1422-6405    

DOI:10.1159/000145793

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

In order to ‘dissect out’ the function of a given region of the brain, the local application of a chemical transmitter probably parallels closely what is actually occurring biologically at the local site. This paper addresses itself to the problem of diffusion of drugs and describes the application of a modern device (the osmotic minipump) which produces a constant flow of minute quantities of the agent into the brain structure. Neurophysiological, behavioural, and histochemical investigations have been carried out in different species. Although the histochemical results of the minipump experiments indicate some spread, yet this seems to be at a concentration which would have no apparent pharmacological action. This was confirmed by our neurophysiological and behavioural studies and also by some recent reports in the literat

ISSN:1422-6405    

DOI:10.1159/000145794

出版商:S. Karger AG    

年代:1983

数据来源: Karger