Unusual eustachian tube mass: glomus tympanicum. (1/22)

SUMMARY: A case of recurrent glomus tympanicum presenting with epistaxis is described. CT and MR imaging revealed a homogeneously enhancing mass extending along the entire course of the eustachian tube, with a portion protruding into the nasopharynx. Glomus tumors tend to spread along the path of least resistance and may extend into the eustachian tube. The unique imaging appearance should place a glomus tumor high on the list of differential diagnoses.  (+info)

The distribution of presumptive thoracic paraganglionic tissue in the common marmoset (Callithrix jacchus). (2/22)

The aortic-pulmonary regions (APR) of seven adult marmosets (Callithrix jacchus) and the region of the right subclavian artery of a further three marmosets were diffusion-fixed with 10% buffered formol-saline solution. In both regions serial 5 microm sections were cut and stained by the Martius yellow, brilliant crystal scarlet and soluble blue method. Presumptive thoracic paraganglionic (PTP) tissue was only observed in the APR. PTP tissue was composed of small groups of cells that varied in size and number. The distribution of the groups of cells was extremely variable, so much so that it would be misleading to attempt to classify their position; they were not circumscribed by a connective tissue capsule, but were always related to the thoracic branches of the left vagus nerve. The cells lay in loose areolar tissue characteristic of this part of the mediastinum and received their blood supply from small adjacent connective tissue arterioles. Unlike the paraganglionic tissue found in the carotid body the cells in the thorax did not appear to have a profuse capillary blood supply. There was, however, a close cellular-neural relationship. The cells, 10-15 microm in diameter, were oval or rounded in appearance and possessed a central nucleus and clear cytoplasm. No evidence was found that these cells possessed a 'companion' cell reminiscent of the arrangement of type 1 and type 2 cells in the carotid body. In conclusion, we found evidence of presumed paraganglionic tissue in the APR of the marmoset which, however, did not show the characteristic histological features of the aortic body chemoreceptors that have been described in some non-primate mammals. A survey of the mediastina of other non-human primates is required to establish whether this finding is atypical for these animals.  (+info)

Hereditary paraganglioma targets diverse paraganglia. (3/22)

Paragangliomas are highly vascularised and often heritable tumours derived from paraganglia, a diffuse neuroendocrine system dispersed from skull base to the pelvic floor. The carotid body, a small oxygen sensing organ located at the bifurcation of the carotid artery in the head and neck and the adrenal medulla in the abdomen, are the most common tumour sites. It now appears that mutations in SDHB, SDHC, and SDHD, which encode subunits of mitochondrial complex II (succinate dehydrogenase; succinate-ubiquinone oxidoreductase), are responsible for the majority of familial paragangliomas and also for a significant fraction of non-familial tumours. Germline mutations in complex II genes are associated with the development of paragangliomas in diverse anatomical locations, including phaeochromocytomas, a finding that has important implications for the clinical management of patients and genetic counselling of families. Consequently, patients with a paraganglioma tumour, including phaeochromocytoma, and a complex II germline mutation should be diagnosed with hereditary paraganglioma, regardless of family history, anatomical location, or multiplicity of tumours. This short review attempts to bring together relevant genetic data on paragangliomas with a particular emphasis on head and neck paragangliomas and phaeochromocytomas.  (+info)

Paraganglial cells of urinary bladder and prostate: potential diagnostic problem. (4/22)

A transurethral prostatic resection for prostatism in a 73 year old man showed a cluster of richly capillarised clear cells originally thought to be indicative of invasive carcinoma. Immunohistochemical studies were carried out on this tissue specimen and three similar cases using a variety of antibodies--Neuron specific enolase, PGP 9.5, chromogranin, synaptophysin, serotonin, somatostatin, substance P, calcitonin, calcitonin gene related peptide, met-enkephalin, VIP, neurofilament, CAM 5.2, S100 protein, prostatic specific antigen and prostatic acid phosphatase. The cellular foci were shown to be composed of paraganglionic cells. The cell clusters were well defined and predominantly comprised clear cells with scanty, fine eosinophilic cytoplasmic granules in three cases. The cell nuclei were round to oval, moderately pleomorphic, with evenly dispersed dense chromatin. It is concluded that the presence of minute foci of paraganglial cells in the bladder wall and prostate gland may be misinterpreted as malignant because of their close association with nerves and their relative rarity. Immunohistochemical staining with neuroendocrine markers should dispel any doubt about their identity.  (+info)

Mechanisms of low-glucose sensitivity in carotid body glomus cells. (5/22)

OBJECTIVE: Glucose sensing is essential for the adaptive counterregulatory responses to hypoglycemia. We investigated the mechanisms underlying carotid body (CB) glomus cells activation by low glucose. RESEARCH DESIGN/METHODS AND RESULTS: Removal of extracellular glucose elicited a cell secretory response, abolished by blockade of plasma membrane Ca(2+) channels, and a reversible increase in cytosolic Ca(2+) concentration. These data indicated that glucopenia induces transmembrane Ca(2+) influx and transmitter secretion. In patch-clamped glomus cells, exposure to low glucose resulted in inhibition of macroscopic outward K(+) currents and in the generation of a depolarizing receptor potential (DRP). The DRP was abolished upon removal of extracellular Na(+). The membrane-permeable 1-oleoyl-2-acetyl-sn-glycerol induced inward currents of similar characteristics as the current triggered by glucose deficiency. The functional and pharmacological analyses suggest that low glucose activates background cationic Na(+)-permeant channels, possibly of the transient receptor potential C subtype. Rotenone, a drug that occludes glomus cell sensitivity to hypoxia, did not abolish responsiveness to low glucose. The association of Glut2 and glucokinase, characteristic of some high glucose-sensing cells, did not seem to be needed for low glucose detection. CONCLUSIONS: Altogether, these data support the view that the CB is a multimodal chemoreceptor with a physiological role in glucose homeostasis.  (+info)

Chronic carotid glomitis and the glomus pulmonale. (6/22)

A histological study was made of the carotid bodies and glomus pulmonale in 50 consecutive subjects over the age of 50 years who came to necropsy to determine if chronic glomitis is confined to the carotid bodies or whether it also occurs in other glomera. Lymphoid aggregates and plasma cell activity were found in the glomus pulmonale just as they were in the carotid bodies. Chronic pulmonary glomitis sometimes occurred in association with chronic carotid glomitis and sometimes independently of this. The mean age of the affected subjects was 76 years in isolated pulmonary glomitis and 79 years in chronic carotid glomitis. Chronic carotid glomitis affected seven (14%) subjects and predominated in women (six to one). In the seven cases of isolated pulmonary glomitis women predominated five to two. Chronic glomitis seems to be a disease process which may affect at least two members of the non-chromaffin paraganglionic system, but it is not clear why focal chronic inflammation affects the glomus pulmonale of one person but not of another.  (+info)

Ultrastructural morphometric observations on the extramural aortico-pulmonary bodies of the domestic fowl. (7/22)

The extramural aortico-pulmonary bodies of the domestic fowl were analysed in electron micrographs by point-counting morphometry. The Type I cell constituted about 34% of the total volume of the parenchyma, whereas the supporting cells (Type II cells, pericytes and Schwann cells) constituted about 26%. The blood capillaries occupied the lowest volume density of about 5%. The mitochondria and the dense-cored vesicles occupied about the same volume (8%) of the Type I cell cytoplasm. The results obtained in the present study are compared with other similar studies on the aortic and carotid bodies of mammals.  (+info)

Aortico-pulmonary bodies in the domestic fowl: ultrastructure, innervation and secretion. (8/22)

In adult and immature domestic fowl, aggregations of large pale-staining cells were found in the wall of the aorta, and of the pulmonary trunk and arteries, in modified regions typified by interruption or loss of elastic laminae and smooth muscle cells. Encapsulated extramural aggregations of similar cells were identified either on the actual surface or well outside the arterial wall of the aorta, and pulmonary trunk and arteries. The electron microscope revealed that the pale cells in these intramural and extramural structures were granular cells characterised by dense-cored vesicles typically about 60-140 nm in diameter. Supporting cells partly invested the granular cells. These intramural and extramural structures are interpreted as aortico-pulmonary bodies. The extramural and to a lesser extent the intramural cells were associated with many axonal endings and fenestrated blood capillaries. The axonal endings formed presumptive afferent, efferent and reciprocal synapses with the granular cells. Both intra- and extramural granular cells displayed evidence of exocytosis and were also shown by autoradiography to handle amines. It is concluded that the ultrastructural features of these aortico-pulmonary bodies resemble those of the carotid body. It is therefore suggested that the aortico-pulmonary bodies of the domestic fowl have a chemoreceptor function similar to that of the carotid body. It is also suggested that they may have a general secretory function.  (+info)

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