Tumours of the adrenal gland and paraganglia.
(1/8)
This classification is arranged in two parts in order to take into account the different origins, structures, and functions of the cortex and medulla. The tabular classification is a simplified version of that suggested for adrenal tumours in man, and includes cortical adenoma and carcinoma, phaeochromocytoma, chemodectoma, neurofibroma, ganglioneuroma and ganglioneuroblastoma, and neuroblastoma. A detailed functional classification is not given, since the hormonal activity of many adrenal tumours in animals is less well known than it is in man. Of the tumour-like lesions listed, cortical hyperplasia is particularly important in several species. (+info)
Hypoxia alters gene expression in human neuroblastoma cells toward an immature and neural crest-like phenotype.
(2/8)
Insufficient oxygen and nutrient supply often restrain solid tumor growth, and the hypoxia-inducible factors (HIF) 1 alpha and HIF-2 alpha are key transcription regulators of phenotypic adaptation to low oxygen levels. Moreover, mouse gene disruption studies have implicated HIF-2 alpha in embryonic regulation of tyrosine hydroxylase, a hallmark gene of the sympathetic nervous system. Neuroblastoma tumors originate from immature sympathetic cells, and therefore we investigated the effect of hypoxia on the differentiation status of human neuroblastoma cells. Hypoxia stabilized HIF-1 alpha and HIF-2 alpha proteins and activated the expression of known hypoxia-induced genes, such as vascular endothelial growth factor and tyrosine hydroxylase. These changes in gene expression also occurred in hypoxic regions of experimental neuroblastoma xenografts grown in mice. In contrast, hypoxia decreased the expression of several neuronal/neuroendocrine marker genes but induced genes expressed in neural crest sympathetic progenitors, for instance c-kit and Notch-1. Thus, hypoxia apparently causes dedifferentiation both in vitro and in vivo. These findings suggest a novel mechanism for selection of highly malignant tumor cells with stem-cell characteristics. (+info)
An immunohistochemical study of human postnatal paraganglia associated with the urinary bladder.
(3/8)
Histological and immunohistochemical methods were used to study pelvic paraganglia in a series of human postnatal specimens ranging in age from 1 month to 6 y. Up to 5 months of age, many of the encapsulated paraganglia contained small pacinian-like sensory corpuscles which occurred either singly or in small clusters, implying an unknown functional interrelationship during this period. In older specimens, this intimate association was not observed since pacinian corpuscles and small nonencapsulated clusters of paraganglion cells were observed only as separate structures. It is suggested that the paraganglion cells may induce the formation of the pacinian corpuscles during fetal development. Immunohistochemistry using the nerve marker protein gene product (PGP 9.5) demonstrated a rich plexus of varicose nerve fibres within the paraganglia which may directly innervate the paraganglion cells and/or be associated with the profuse vascular supply. A similar density of vasoactive intestinal polypeptide-containing nerves was also demonstrated while some of the nerves contained calcitonin gene related peptide or substance P. The paraganglion cells stained positively for tyrosine hydroxylase, dopamine-beta-hydroxylase and neuropeptide Y, but not for phenylethanolamine N-methyltransferase. This combination of immunostaining confirms them as a rich source of noradrenaline. (+info)
Malignant paraganglioma of the mesentery: a case report and review of literature.
(4/8)
Immunohistochemical evidence for the occurrence of vasoactive intestinal polypeptide (VIP)-containing nerve fibres in human fetal abdominal paraganglia.
(5/8)
The abdominal paraganglia in man represent a major source of catecholamines, and perhaps peptide hormones, during the fetal period. The nature of the innervation of the abdominal paraganglia was studied immunohistochemically by utilising antibodies to vasoactive intestinal polypeptide, enkephalin, substance-P and somatostatin. The paraganglia showed an abundant network of VIP-immunoreactive fibres, and similar nerve fibres were found within nerve bundles of the preaortic sympathetic plexus. Occasionally, VIP-immunoreactive fibres were seen within the prevertebral ganglia, but stained cell bodies were never observed. It may be suggested that VIP-containing nerves could regulate a secretory response from fetal human abdominal paraganglia. (+info)
A study of the distribution of chromaffin-positive (CH+) and small intensely fluorescent (SIF) cells in sympathetic ganglia of the rat at various ages.
(6/8)
Small intensely fluorescent (SIF) and chromaffin-positive (CH+) cells were independently investigated by formol-induced fluorescence and by chromaffin techniques in the superior cervical, thoracic and coeliac-mesenteric ganglia of neonatal (2--10 days), adolescent (2--4 months) and adult (6--15 months) rats. Identification of CH+ cells was facilitated by glutaraldehyde fixation prior to chromatin. Intraganglionic blood vessels were displaced by antemortem injection of either India ink or the fluorescent dye Thioflavine-S. SIF and CH+ cells were randomly distributed through the ganglia, either singly or in pairs related to principal neurons, or in variably-sized, highly vascularized groups. In chromaffin preparations these groups either consisted entirely of CH+ cells or else they contained a mixture of CH+ and CH- cells. CH+ cells were present in some adolescent and adult ganglia of all types, and in the neonatal coeliac-mesenteric ganglion at 10 days. In neonatal material generally, SIF cells were mostly green fluorescent, occurring separately or in homogeneous or mixed groups, but both yellow and green cells occurred in coeliac-mesenteric ganglia at 10 days. All ganglia in adolescent and older animals contained both yellow and green cells. There were more green than yellow cells, and more SIF than CH+ cells in all ganglia studied. (+info)
The ultrastructure of hypertrophied paraganglia in aged rats.
(7/8)
The catecholamine-storing cells in the paraganglia of old rats showed structural characteristics common to adrenomedullary and paraganglionic cells of young animals. No sign of degeneration was found. Lipofuscin pigment was observed in most cells. The paraganglia were innervated and well supplied by fenestrated sinusoidal capillaries. Their fine structure suggests active endocrine function. An increase in the total bulk of the paraganglia in old rats suggests that they have a physiological role in senescence. (+info)
IGF2 expression is a marker for paraganglionic/SIF cell differentiation in neuroblastoma.
(8/8)
Neuroblastoma is a childhood tumor of the sympathetic nervous system. Observations in the Beckwith-Wiedemann syndrome suggest that sympathetic embryonal cells with an abundant expression of the insulin-like growth factor 2 gene (IGF2) may be involved in the genesis of low-malignant infant neuroblastomas. We have therefore compared the cell type-specific IGF2 expression of the human sympathetic nervous system during early development with that of neuroblastoma. An abundant expression in normal sympathetic tissue was specific to extra-adrenal chromaffin cells, ie, paraganglia and small intensely fluorescent (SIF) cells, whereas sympathetic neuronal cells were IGF2-negative. A subpopulation of neuroblastomas expressed IGF2, which correlated with an early age at diagnosis, an extra-adrenal tumor origin, and severe hemodynamic signs of catecholamine secretion. Histologically IGF2-expressing tumors displayed a lobular growth pattern, and expression was restricted to the most mature and least proliferative cells. Typically, these cells were morphologically and histochemically similar to paraganglia/SIF cells and formed distinct ring-like zones in the center of the lobules around a core of apoptosis-like tumor cells. The similarities found between IGF2-expressing neuroblastoma cells and paraganglia/SIF cells in terms of histological features, anatomical origin, and age-dependent growth suggest a paraganglionic/SIF cell lineage of most infant tumors and also of extra-adrenal tumors diagnosed after infancy. Furthermore, since paraganglia/SIF cells undergo postnatal involution, the same cellular mechanism may be responsible for spontaneous regression in infant neuroblastoma. (+info)