摘要:

In vitro cloning of embryonic cells is a powerful tool for understanding the mechanism and timing of cell differentiation during development. Although in vitro mass culture of chondrogenic mesenchymal cells and clonal culture of already differentiated chondrocytes have been reported, clonal culture of chondrogenic ectomesenchymal cells at a postmigratory stage but prior to chondrogenic cell condensation has not been reported, nor have cartilage nodules been obtained in clonal culture. We cloned chick mandibular ectomesenchymal cells from HH stage 17 chick embryos. These cells produced clones that underwent chondrogenesis as determined by the presence of alcian blue-staining extracellular matrix and immunohistochemical visualization of type II collagen. Chondrogenic clones formed three-dimensional cartilaginous nodules. This postmigratory mandibular ectomesenchyme is heterogeneous, containing two different types of unipotential cells that give rise to chondrogenic and nonchondrogenic cells, plus bipotential cells that give rise to both chondrogenic and nonchondrogenic cells.

ISSN:1422-6405    

DOI:10.1159/000147646

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Lectin binding histochemistry was used to investigate the glycoconjugate saccharidic moieties in the respiratory epithelium of human fetuses ranging in age from the 8th to the 12th week of gestation. The distribution and changes in the sugar residues of the glycoconjugates at the level of the basal cells, the bathyprismatic cells and the bathyprismatic ciliated cells are reported. PNA and SBA allowed the identification of some ‘elongated cells’, which were characterized by lectin-reactive supranuclear granules. These epithelial cells, which have not previously been identified using conventional histochemical methods, might be the precursors of secretory ce

ISSN:1422-6405    

DOI:10.1159/000147647

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Condylar growth was studied after an operation simulating functional orthodontic appliances. Twenty-five rabbits underwent a surgical operation for the induction of premature synostosis to displace the glenoid fossa posteriorly during growth. Twenty-five control rabbits underwent sham operations. At the age of 15 days, 10 experimental and 10 control animals and, at the age of 20 days, 5 experimental and 5 control animals were killed. Their mandibular condyles were organ-cultured for 3 h in the presence of radiolabelled sulphur. The condyles were used for autoradiographic purposes. Digital image analysis of autoradiograms of histological sections showed synthesis of glycosaminoglycans to have increased from the anterior to the posterior direction. This increase was more marked in experimental animals than in the condyles of control animals. Ten experimental and 10 control animals were killed at the age of 15 days, and mandibular condyles were organ-cultured for 1, 4 and 7 days. Differentiation of proliferating prechondroblasts into hypertrophied chondrocytes continued under organ culture conditions. A marked decrease in the proliferating cell layer was noticed, especially in control condyles. Hypertrophy was faster and came closer to the surface of the condyle in the anterior region of the condyle. This was most marked in the condyles of experimental animals. The results indicate that a procedure carried out on the glenoid fossa with the same effect as functional appliances increases the synthesis of extracellular matrix in the posterosuperior region of the mandibular condyle.

ISSN:1422-6405    

DOI:10.1159/000147648

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Samples were taken at slaughter from heart and both locomotor and nonlocomotor muscles from animals of similar body weight but adapted to different levels of activity: three horses and three steers. All samples were analyzed biochemically to measure the activity of key metabolic enzymes. The skeletal muscles were analyzed histochemically for fibre type composition, fibre area and capillary supply. The general pattern of differences in fibre type composition and metabolic profile between muscle groups was similar in both horses and steers. The hearts of both species had high citrate synthase (CS), 3-OH-acylCoA-dehydrogenase (HAD) and hexokinase (HK) and low lactate dehydrogenase (LDH) activities. In both species, deep portions of muscles and muscles localized deeper in the body had a more oxidative metabolic profile than superficial portions and muscles. Taking all muscles into account, it was found that CS and HAD were higher and LDH lower in horse than in steer muscles. Horse muscles contained more type ΠA fibres and had a higher capillary supply than steer muscles. There was no difference between the two species regarding mean fibre area. The adaptation of the horse to a higher level of activity in comparison with steers was reflected in a higher oxidative capacity, better vascularization and a larger proportion of type IIA fibres. It was also obvious from these results that the ATPase fibre-typing system does not reflect the metabolic profile of a muscle

ISSN:1422-6405    

DOI:10.1159/000147649

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

The distribution and morphological features of cardiac musculature in rat cranial venae cavae were examined by light and transmission electron microscopy. Cardiac myocytes are encountered from the right atrium to the root of the subclavian vein. The musculature consists of several well-developed circular or spiral myocyte layers. The ultrastructure of myocytes in the cranial venae cavae exhibits a similar structure to that of atrial myocytes. Abundant myofibrils and mitochondria are detected within the cytoplasm of these myocytes, suggesting an active contraction of the musculature. Characteristic caveolae are accumulated near the sarcolemma of cardiac myocytes in the cranial venae cavae showing their high pinocytotic activity. Immunohistochemical analysis reveals the presence of an atrial natriuretic polypeptide-like substance in the cranial vena cava and the proximal portion of the subclavian vein. Ultrastructural studies also demonstrate the distribution of atrial granules within the musculature. This musculature in the vena cava may be considered part of the endocrine atrium.

ISSN:1422-6405    

DOI:10.1159/000147650

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Dynorphin and α-neoendorphin bind to the K subtype of opioid receptors and have been shown to inhibit the release of noradrenaline from cardiac sympathetic axons. The purpose of this study was to elucidate the endogenous localization of dynorphin and α-neoendorphin in the guinea pig heart. This goal was achieved by double- and triple-labelling immunofluorescence. Dynorphin- and α-neoendorphin-immunoreactive nerve fibers were numerous around coronary blood vessels and among cardiomyocytes. They also contained immunoreactivities to the rate-limiting enzyme of catecholamine synthesis tyrosine hydroxylase and to neuropeptide Y. These fibers disappeared in response to chemical sympathectomy (6-hydroxydopamine treatment). In contrast, substance P/calcitonin gene-related peptide-immunoreactive axons of sensory origin did not contain dynorphin and α-neoendorphin immunoreactivities and were unaffected by chemical sympathectomy. The findings demonstrate that immunoreactive dynorphin and α-neoendorphin are contained in postganglionic sympathetic nerve fibers innervating coronary blood vessels and cardiac muscle. Therefore, the inhibitory effect of these peptides upon noradrenaline release from the sympathetic terminal may well be an autoinhibitory feedback

ISSN:1422-6405    

DOI:10.1159/000147651

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

Immunohistochemical detection of the neurone-specific ubiquitin hydrolase protein gene product 9.5 (PGP 9.5) has been applied to the normal adult human adrenal cortex to define overall patterns of innervation. Three distinct types of nerve morphology were noted in the cortex: large nerve trunks traversing the cortex to the medulla, a complex, branching network of slender nerve bundles and individual nerve fibres. These were more abundant in the head and body than in the alae and tail. Varicosities suggested local neurotransmitter release. Nerve fibres were also identified in the muscular wall of the central vein, which are apparently neither noradrenergic nor cholinergic. These data are in support of a direct role for nerves in the control of adrenocortical function and/or vascular responses in man.

ISSN:1422-6405    

DOI:10.1159/000147652

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

To study the process of recovery from facial palsy experimentally, the location of cranial motoneurons supplying the posterior belly of the digastric muscle (PDG) and the extratemporal portion of the facial nerve trunk was examined in a double-labeling paradigm using two retrograde tracers in the adult guinea pig of which the facial nerve had been surgically injured. In different stages after the induced facial palsy had recovered functionally (4-13 weeks after the surgical operation), wheat germ-agglutinated horseradish peroxidase (WGA-HRP) was injected into the PDG and Fluoro-Ruby (FR) was applied to the proximal cut end of the extratemporal portion of the facial nerve trunk. Distribution of neurons retrogradely labeled with WGA-HRP and/or FR was plotted in the brainstem and compared with that of the controls. In the intact cases, HRP-labeled neurons were restrictedly seen in the accessory facial nucleus (Acs7), while FR-labeled neurons were found within the main facial nucleus (FMN). In the axotomized cases: (1) HRP-labeled neurons were seen diffusely in the Acs7 as well as in the FMN, where normal myotopical representation no longer seemed to be maintained. (2) FR-labeled neurons were also observed diffusely in the FMN and the Acs7. (3) A considerable number of neurons were doubly labeled with WGA-HRP and FR in both the Acs and the FMN in cases with shorter survival periods (4-7 weeks), but not in cases with longer survival periods (12-13 weeks). Thus, new findings show that connections are temporarily maintained by single, facial motoneurons with axon collaterals to multiple muscle targets in adult mammals. These transient projections may also serve as an ideal model to study the mechanisms of the regeneration occurring in the process of facial palsy recovery.

ISSN:1422-6405    

DOI:10.1159/000147653

出版商:S. Karger AG    

年代:1994

数据来源: Karger

摘要:

A study of 100 upper extremities from fresh human cadavers injected with colored latex or india ink and gelatin revealed the vascularization of the flexor pollicis longus muscle (FPL) tendon. This tendon was found to be vascularized from four different sources with anastomoses between them. Very rich anastomoses were observed between the terminal segments of the arterial branches which form the intratendineal network of the tendon itself.

ISSN:1422-6405    

DOI:10.1159/000147654

出版商:S. Karger AG    

年代:1994

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147655

出版商:S. Karger AG    

年代:1994

数据来源: Karger