Radiotherapy in the management of chemodectomas of the carotid body and glomus vagale

To determine whether thyroid hormones, triiodothyronine (T3) and thyroxine (T4), have any direct, nongenomic effects on vascular smooth muscle cells, we evaluated the effects of these hormones on rat coronary arteries. Bolus injection of T3 or T4 elicited a transient, dose-dependent decrease in coronary perfusion pressure (CPP), as well as an increase in arterial vasodilation. Vasodilation occurred immediately after injection, peaked at 15 seconds, and lasted 80 seconds. Reverse T3 had no effect on CPP or vasodilation. The rapidity of these effects suggests that they are not mediated by the T3-nuclear receptor, but are direct, nongenomic effects of thyroid hormones. Our results also suggest that thyroid hormones may play a role in preventing myocardial ischemia by inducing coronary artery vasodilation.     

Modulation of junctional conductance between rat carotid body glomus cells by hypoxia, cAMP and acidity

Short-term cultures of glomus cells (up to seven days), were employed to study intercellular electrical communications. Bidirectional electric coupling was established under current clamping after impaling two adjacent glomus cells with microelectrodes, and alternate stimulation and recording. Their resting potential (Vm) and input resistance (Ro) were thus measured. Both coupled cells were then voltage clamped at a level between their Vms. Current pulses applied to either cell elicited a transjunctional voltage (Vj) and current (Ij), used to calculate the junctional conductance (Gj). Gj was 1.52+/-0.29 nS (mean+/-S.E.; n=147). Vj linearly influenced Gj, suggesting ohmic junctions. Gj was not affected by Vm in 50% of the cases. However, there was Vm-dependence in the others, but voltage changes had to be large (>+/-40 mV from the Vm). Therefore, physiologically or pharmacologically induced glomus cell depolarization or hyperpolarization may not significantly affect intercellular coupling unless there are large variations in Vm. Hypoxia (induced by Na2S2O4 1 mM or 100% N2) decreased Gj in 60-80% of the pairs while producing tighter coupling in the rest. Similar effects were obtained when the medium was acidified with lactic acid 1-10 mM. Cobalt chloride (3 mM) prevented, diminished or reversed the changes in Gj observed during low PO2, suggesting that [Ca2+]i changes are important in hypoxic uncoupling. However, non-specific cationic effects of Co2+ have not been ruled out. Applications of the membrane-permeant dB-cAMP 1 mM tightened coupling in almost all cell pairs. This is important because endogenous cAMP increases during hypoxia. Our results suggest that multiple factors modulate junctional conductance between glomus cells. Changes in Gj by 'natural' stimuli and/or cAMP may play an important role in chemoreception, especially in titrating the release of transmitters toward the carotid nerve terminals.     

Chemodectoma secreting carotid glomus: characteristics and contribution of magnetic resonance imaging. Apropos of 2 cases

Nurses must become aware of the high number of women affected by substance abuse during the childbearing years and the related health consequences. Health care providers also need to develop and maintain a positive attitude toward mothers who use cocaine, assess the needs of each individual mother and her infant, and become familiar with a wide range of available resources to address the identified needs of these multirisk families. Finally, nurses can assist families with a history of maternal cocaine use by supporting the development of appropriate parenting skills. Part 2 will describe strategies for nurses to work with mothers and children in the next issue of Pediatric Nursing.     

Norepinephrine inhibits a toxin resistant Ca2+ current in carotid body glomus cells: evidence for a direct G protein mechanism

The rabies virus glycoprotein molecule (G) can be divided into two parts separated by a flexible hinge: the NH2 half (site II part) containing antigenic site II up to the linear region (amino acids [aa] 253 to 275 encompassing epitope VI [aa 264]) and the COOH half (site III part) containing antigenic site III and the transmembrane and cytoplasmic domains. The structural and immunological roles of each part were investigated by cell transfection and mouse DNA-based immunization with homogeneous and chimeric G genes formed by fusion of the site II part of one genotype (GT) with the site III part of the same or another GT. Various site II-site III combinations between G genes of PV (Pasteur virus strain) rabies (GT1), Mokola (GT3), and EBL1 (European bat lyssavirus 1 [GT5]) viruses were tested. Plasmids pGPV-PV, pGMok-Mok, pGMok-PV, and pGEBL1-PV induced transient expression of correctly transported and folded antigens in neuroblastoma cells and virus-neutralizing antibodies against parental viruses in mice, whereas, pG-PVIII (site III part only) and pGPV-Mok did not. The site III part of PV (GT1) was a strong inducer of T helper cells and was very effective at presenting the site II part of various GTs. Both parts are required for correct folding and transport of chimeric G proteins which have a strong potential value for immunological studies and development of multivalent vaccines. Chimeric plasmid pGEBL1-PV broadens the spectrum of protection against European lyssavirus genotypes (GT1, GT5, and GT6).     

Functional mapping of glomus tumors reveals underlying embryology

A human mandibular osteosarcoma cell line, HMOS-1, with osteoblastic phenotypes and tumor-genicity was established. The cell line showed high alkaline phosphatase (ALP) activity immediately after seeding, with its peak around the 7th to 10th day of culture (1.44 mumol/min/mg protein). Parathyroid hormone (PTH) enhanced the ALP activity as well as intracellular cAMP production in a concentration-dependent manner. The effects of PTH on both ALP activity and cAMP production were expressed more strongly at the end stage of logarithmic cell growth than at the resting stage. 1,25 (OH)2D3 also stimulated the ALP activity, but its effect was low and was not different in any of the different culture stages. When these cells were transplanted to BALB/C nude mice, similar tumours to the original one, with abundant osteoids were observed. However, th e synthesis of type 1 collagen was not detected in the culture medium. The results indicate that the HMOS-1 cell line expresses an immature pre-osteoblastic phenotype. Because of these characteristics, HMOS-1 cells should be useful, not only in studies on the differentiated phenotypes of human osteoblasts, but also in studies on the diagnosis, treatment and aetiology of human osteosarcoma of the jaw.     

Plastic repair of the carotid artery in carotid endarterectomy

The work is based on an analysis of results of 70 carotid endarterectomies performed on 68 patients aged from 43 to 67 years. 53% of the patients were operated upon at the stage of a relative compensation of brain blood circulation. Multiple character of injuries of the brachiocephalic arteries took place in 70.5% of the cases. Plasty of the internal carotid artery is thought by the authors to be necessary by means of using a flap of lyophylized allopericardium, with the diameter of its orifice less than 8 mm.     

High PCO does not alter pHi, but raises [Ca2+]i in cultured rat carotid body glomus cells in the absence and presence of CdC12

We measured the effect of high PCO (500-550 Torr) on the pHi and [Ca2+]i in cultured glomus cells of adult rat carotid body (CB) as a test of the two models currently proposed for the mechanism of CB chemoreception. The metabolic model postulates that the rise in glomus cell [Ca2+]i, the initiating reaction in the signalling pathway leading to chemosensory neural discharge, is due to [Ca2+] release from intracellular Ca2+ stores. The membrane potential model postulates that the rise in [Ca2+]i comes from influx of extracellular Ca2+ through voltage-dependent Ca2+ channels (VDCC) of the L-type. High PCO did not change pHi at PO2 of 120-135 Torr, showing that CO-induced changes in [Ca2+]i are not due to changes in pHi. High PCO caused a highly significant rise in [Ca2+]i from 90+/-12 nM to 675+/-65 nM, both in the absence and in the presence of 200 microM CdCl2, a potent blocker of L-type VDCCs. This result is fully consistent with release of Ca2+ from glomus cell intracellular stores according to metabolic model, but inconsistent with influx of extracellular Ca2+ through VDCCs according to the membrane potential model.     

Malignant glomus tumor: a case report and review of the literature

This report concerns a malignant glomus tumor, a rare soft tissue tumor that was examined immunohistochemically and ultrastructurally. It occurred in a 44-year-old male patient who had suffered from dull pain and stiffness in the right thigh for 10 months. Radiographic examination revealed a well-defined osteolytic lesion in the diaphysis of the right femur. Hypervascularity of the tumor was observed angiographically. Computed tomographic and magnetic resonance examinations showed an intramuscular mass invading the marrow space of the femur. Wide resection was performed after open biopsy. Histologically, round to polygonal tumor cells revealed a uniform appearance of round to ovoid nuclei with single large nucleoli and slightly eosinophilic cytoplasm, forming solid sheets of cells interrupted by vessels of varying size. A few mitotic figures and vascular invasion were observed. Immunohistochemically, vimentin and alpha-smooth muscle actin were stained intensely, and muscle actin was positive for tumor cells of the perivascular area. Tumor cells were negative for desmin, factor VIII-related antigen, S-100 protein, neurofilament, cytokeratin, and epithelial membrane antigen. Ultrastructurally, tumor cells were characterized by many cytoplasmic processes, pinocytotic vesicles, plasmalemmal dense plaques, and scattered microfilaments in the cytoplasm. Few cell junctions and focal basement membrane-like structures were observed. No recurrence or metastasis was noted 57 months after operation. This case was considered to be a malignant glomus tumor, that is, a glomangiosarcoma arising de novo.     

Detection of glomus tumor of the finger by dedicated MRI at 0.1 T

Three glomus tumors of the fingers were detected using a dedicated hand and wrist low field (0.1 T) MR imager equipped with solenoidal coils allowing a FOV of 2 cm. Three-dimensional T1-, T*2-, or T2-weighted images were used (8 contiguous slices of 2 mm thickness). Glomus tumors had low or intermediate signal intensity (2 cases) or no signal (1 case) on T1-weighted images. On T*2- or T2-weighted images they had high signal intensity. MRI findings correlate well with surgery and biopsy.     

Biology and growth velocity of tumors of the globus jugulotympanicum and glomus caroticum

BACKGROUND: Paragangliomas (glomus tumors) of the head and neck are rare tumors, arising from the paragangliomatous tissue either of the carotid region or the jugular or the tympanic region. This study was conducted to investigate the possible differences in the tumor biology of these lesions depending on their site of origin. METHODS: Nineteen specimens (10 jugulotympanic and 9 carotid glomus tumors) were investigated by quantitative DNA measurements and immunohistochemical assessment of proliferation markers (PCNA, Ki67), oncogenes (p53, nm23), different cell surface antigenes (CD44 4/5 and 6, CD54, CD106), and bcl 2 as a marker for apoptosis. RESULTS: Depending on the location of the tumors these measurements revealed significant differences in tumor biology with higher proliferation scores and a higher number of aneuploid tumors in those of the carotid region, suggesting a more aggressive behavior compared to those of the jugulotympanic region. CONCLUSIONS: The results also indicate a difference between the two groups in the risk of developing metastases or recurrent disease. They generally help to enhance our understanding of the biology of paragangliomas of the head and neck.     

Influence of the status of the contralateral carotid artery on the outcome of carotid surgery

This is a preliminary report of four cases of meniscal displaced tears: two bucket handle medial meniscus tears, one complex tear in the avascular zone or lateral meniscus, and one longitudinal full-thickness tear on the lateral meniscus. These tears were treated by applying hi-frequency current stimulation to the tissues and obtaining total meniscal visual healing on a second arthroscopic view after 6 weeks.     

Neurovascular considerations in surgery of glomus tumors with intracranial extensions

Paragangliomas of the skull base, by virtue of their location, locally infiltrative behavior, and vascular nature, are difficult tumors to resect. Surgical removal is especially complicated when intracranial extensions are encountered. Our experience with a one-stage resection of intracranial extensions of glomus tumors in 20 patients is presented. These 20 patients had a total of 29 paragangliomas: 23 glomus jugulare or tympanicum tumors, 5 carotid body tumors, and 1 pterygopalatine lesion. Ten patients had intradural extension; the other 10 had intracranial extradural tumors. The primary complicating treatment factor was the loss of surgical planes in 6 patients with prior surgery and or radiotherapy. The presence of multiple paragangliomas (20%) and catecholamine secretion by the tumors (15%) complicated surgical treatment as well. Surgical morbidity was primarily related to deficits of lower cranial nerves (50%).     

Tumor of the carotid body

Clinical and X-ray examinations for hip dysplasias in 500 babies in one ward showed 40% wrongly positive and 5.6% wrongly negativ (silent or masked) results, control of which necessiates roentgenograms in the second or third month or coltrolled spreading immediately after birth.     

MR tomography and MR angiography of an extensive glomus jugulare tumor

The diagnosis of a glomus jugulare tumour was established by MR tomography and MR angiography. MR tomography demarcated the tumour from the surrounding tissue and MR angiography showed the vascularity of the glomus tumour.     

A morphological study of the carotid body and the fibre content of carotid nerve in the buffalo

In the buffalo the carotid body is located in the periarterial connective tissue of the occipital artery immediately cranial to the bifurcation of the common carotid artery. The carotid body is lobulated and does not appear to contain chromaffin tissue. Nerve terminals have been seen in close relation to the glomus cells. A quantitative study of the fibre content of the carotid nerve and the carotid body has also been made. The myelinated fibres in the carotid nerve range from 278 to 473, with a mean of 368 +/- 39 fibres. The histogram of myelinated fibres is distinctly unimodal. Of the myelinated fibre population, 55.4% of fibres have diameters of 2 mum, 34.1% of 4 mum, 9.5% of 6 mum and 1% have diameters of 8 mum. The mean greatest sagittal sectional area of the carotid body is 0.58 +/- 0.09 mm2. The mean density (per mm2) of glomus cells is 9,216 +/- 378. It appears that the organ is highly vascular (473 +/- 56 blood vessels/mm2 area). The mean size of the glomus cells is 7.85 +/- 0.46 mum X 10.02 +/- 0.64 mum (short diameter X long diameter), whereas the mean size of their nuclei is 4.96 +/- 0.19 mum X 5.52 +/- 0.27 mum.     

Oligosymptomatic glomus tympanicum and caroticium with two different histological pictures

Though glomus tumors have been relatively frequently reported, there is very little material about their differential diagnostic problems. The authors present a case of glomus tympanicum and glomus caroticum with only otological symptoms, facial paralysis and traumatic arterio-venous shunts in the neck. These two tumors had few different patterns of glomus tissue.     

CT angiography of the carotid artery

CT angiography shows promise as a noninvasive method to display carotid vascular pathology. This article discusses technique, stenosis measurements, pitfalls, strengths, and weaknesses of CT imaging of the carotid artery.     

Dopamine-secreting glomus vagale: a case report and histopathologic correlation

The effect of atorvastatin, a CYP3A4 substrate, on the pharmacokinetics of terfenadine and its carboxylic acid metabolite, fexofenadine, were evaluated. Single 120-mg doses of terfenadine were given 2 weeks apart to healthy volunteers with 80-mg daily doses of atorvastatin administered from 7 days before through 2 days after the second terfenadine dose. Concentrations of terfenadine and fexofenadine were measured for 72 hours after each terfenadine dose. Administration of terfenadine alone or in combination with atorvastatin produced no alterations in the QTc interval. For terfenadine, atorvastatin coadministration produced an 8% decrease in maximum concentration (Cmax), a 35% increase in area under the concentration-time curve extrapolated to infinity (AUC0-infinity), and a 2% decrease in elimination half-life (t1/2). For fexofenadine, atorvastatin coadministration produced a 16% decrease in Cmax, a 2% decrease in AUC0-infinity and a 51 % increase in t1/2. None of these changes achieved statistical significance. Coadministration of atorvastatin with terfenadine does not result in a clinically significant drug interaction. Because 80 mg is the highest atorvastatin dose used clinically, drug interactions mediated by CYP3A4 inhibition are unlikely in clinical practice.     

Prospective study of carotid endarterectomy and contralateral carotid occlusion

A total of 700 patients who had carotid endarterectomy (CEA) in the UK and Ireland during a 6-month interval between March and August 1994 were studied prospectively. Some 108 patients (15.4 per cent) had a contralateral internal carotid artery occlusion. Previous reports have shown an associated stroke rate of about 10 per cent in these patients. This study assessed complications and outcome for patients undergoing CEA with contralateral internal carotid artery occlusion compared with those without. The indications for surgery were comparable between the two groups although the patients with occlusion had a slightly higher incidence of arrhythmia and stroke. Intraoperative shunts were used in a significantly higher proportion of those with occlusion (83.3 versus 64.7 per cent, P = 0.0001). The combined death and stroke rate for patients with occlusion was 5.6 per cent compared with 2.4 per cent for the remainder (P not significant). On the basis of the present data, CEA with a contralateral carotid artery occlusion carries only a slight increase in the rate of postoperative stroke and death. This increase was not statistically significant and is lower than that reported previously.