摘要:

Multilamellar glial envelopes of synapses were observed in an ultrastructural study of the pontine nuclei of cats. They consist of several concentric coils, representing lamellar expansions of the astrocytic processes. Glial envelopes completely wrap various synapses (axodendritic, axospinous, glomerulus-like complexes, and contacts between vesicle containing profiles). The possibility that multilamellar glial envelopes might play a role in isolating and protecting diverse neurotransmitters in the pontine nuclei from loss and mingling is discussed.

ISSN:1422-6405    

DOI:10.1159/000146520

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

To evaluate the capacity for growth of cartilage in vitro, the cartilaginous nasal septum was cultured in a serum-free medium in short- and long-term incubation periods. The proliferative activity was assessed by relating counts per minute (cpm) obtained in the liquid scintillater after [3H]-thymidine incorporation with the DNA content of the tissue under investigation. Cell proliferation was interpreted as being synonymous with the DNA synthesizing activity or the cpm/µg DNA ratio. Short-term incubation (24 h) tended to show the same proliferative activity which we have previously found in vivo and as autotransplants, showing that the presence of serum seems to be of little importance under these conditions. Long-term incubation in a serum-free medium tended to show a gradual loss of proliferative activity, emphasizing the need for either serum or other growth-promoting factors as necessary for continued normal proliferation of cartilage in vitro

ISSN:1422-6405    

DOI:10.1159/000146521

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Bovine pancreatic endocrine cells were investigated by light microscopic immunohistochemistry. Serotonin-immunoreactive cells as well as insulin-, glucagon-, somatostatin-, bovine pancreatic polypeptide (BPP)-immunoreactive cells were detected in the pancreatic islets. Generally, insulin-immunoreactive cells were distributed throughout the islet and the others took peripheral location. Since the distribution and shape of serotonin-immunoreactive cells were very similar to glucagon- and BPP-immunoreactive cells, serial sections were restained by using the elution method. All glucagon- and BPP-immunoreactive cells also showed serotonin immunore activity but glucagon and BPP immunoreactivities were never observed to be colocalized in the same cell. A small number of serotonin-immunoreactive cells were observed that showed serotonin immunoreactivity only.

ISSN:1422-6405    

DOI:10.1159/000146522

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The choroid plexus and its associated epiplexus cells in the fourth ventricle in cats were studied with scanning and transmission electron microscopy (SEMTEM) following a cisternal injection of crotoxin complex (phos-pholipase A2). In SEM the epiplexus cells of the control animals were predominantly stellate with long radiating processes. At 2 h after the administration of crotoxin complex, these radiating processes flattened out forming sheet-like membranes covering the ventricular surface of the choroid epithelial cells. The membranous coverings remained extended in 5-hour-survival cats. Numerous blebs of different sizes were observed in areas that were not covered by the cytoplasmic membrane in 5-hour animals. Some of the blebs appeared to have ruptured. InTEM, the microvilli of the choroid epithelial cells in crotoxin complex-treated rats were dilated. The luminal surface of the epithelial cells showed eruption of blebs filled with amorphous materials. Pinocytotic vesicles increased in number in the apical cytoplasm. The lumen of the ventricle often contained portions of cytoplasm believed to be derived from the extrusion of the blebs.These appeared to be engulfed by the overlying epiplexus cells. It was concluded that the injected crotoxin complex stimulated both the secretory as well as pinocytotic activity of the choroid epithelial cells. The phagocytosis of the secretory products from the epithelial cells by epiplexus cells suggests a close functional relationship between the two cell types.

ISSN:1422-6405    

DOI:10.1159/000146523

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

In order to investigate the formation of alveolar pores, lungs of rats, after intratracheal perfusion of glutaraldehyde, are processed at postnatal days 1,1,14,16 and 21 for light and transmission electron microscopy and at days 7 and 16 for scanning electron microscopy. The initial low secondary crests of day 1 rapidly elongate to pleats subdividing the primary saccules. The ledges of some pleats partly grow toward each other as ring like diaphragms, leaving openings whose boundary is composed of alveolar epithelium separated by a basal lamina from a connective tissue sheath with capillaries. At day 7, in scanning electron microscopy the lumina of some rudimentary alveoli communicate by apertures of different sizes, as a result of the outgrowth of curved alveolar pleats which narrow to a ringlike aperture. The interalveolar openings observed in scanning electron microscopy resemble those investigated by light and transmission electron microscopy. The number of interalveolar pores increases from day 7 on; they become more and more frequent at days 14,16 and 21, respectively. It appears that alveolar multiplication in newborn rats proceeds not only by segmentation of terminal respiratory units but also by compoundment of septa. The difference between genuine pores and transsections of folds in transmission electron microscopy will be given closer attention in this study. Also, the incidence and location of type II pneumocytes during rapid enlargement of the alveolar surface area is discussed.

ISSN:1422-6405    

DOI:10.1159/000146524

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The feline gastric microvasculature was studied by corrosion of the injected vascular bed, which allowed evaluation of the vascular pattern of the different tunics. The serosal pattern consisted of numerous interconnected capillary vessels, forming a delicate network. Submucosal arteries supplied the muscular tunic through numerous anastomosing vessels that followed the direction of the smooth muscle fibers. The entire mucosal tunic was supplied by arterioles derived from the submucosal plexus; these gave rise to capillaries that surrounded the gastric glands and terminated in a diffuse, anastomosing subepithelial capillary network. Venules coursed through the mucosa in a perpendicular manner, forming submucosal veins.

ISSN:1422-6405    

DOI:10.1159/000146525

出版商:S. Karger AG    

年代:1988

数据来源: Karger