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At least 973 records · Page 54Linked to original sources
PubMed1994

Differences in a K current in Schwann cells from normal and neurofibromatosis-infected damselfish.

Patch clamp techniques were used to study whole cell ionic currents in Schwann cells (SC) from a tropical marine fish, the bicolor damselfish, Pomacentrus partitus. The bicolor damselfish is affected by a disease termed damselfish neurofibromatosis (DNF), being developed as an animal model of neurofibromatosis-type 1 (NF1) in humans. NF1 affects SC, fibroblasts, and perineurial cells. The sole depolarization-activated ionic current present in cultured SC from normal fish peripheral nerve and from neurofibromas of fish with induced or spontaneously occurring DNF was an inactivating K+ current (K current), with a strong dependence on the Nernst potential for K+. This K current activated at depolarizations to -40 mV and above and inactivated during a maintained test pulse (0.2-1 s), but inactivation was significantly greater in tumored SC. Both currents were inhibited by 4-aminopyridine (Kd approximately 1 mM) and by dendrotoxin (15 microM) but were insensitive to extracellular tetraethyammonium (< or = 150 mM), indicating that the whole cell currents were similar pharmacologically. The currents could be distinguished on the basis of their sensitivity to depolarized holding potential, with normal cells less sensitive. Half-inactivation of the current was -32 mV in normal cells and -38 mV in tumored cells. Inactivation curves constructed from the average normalized current for many SC were significantly different in normal and tumored cells. When the depolarized holding potential was maintained between test depolarizations, greater voltage-dependent inactivation in tumored cells was apparent. Normal cells maintained an average of 36% of peak current at a holding voltage of -40 mV, while in tumored cells this average was 12%, a significant difference.

4-Aminopyridine↗
PubMed2003

Voltage-Gated ion currents of schwann cells in cell culture models of human neurofibromatosis.

K(+) (K) channels play a role in the proliferation of many cell types in normal cells and certain disease states. Several laboratories have studied K currents in cultured Schwann cells from models of the human diseases, neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). These diseases are characterized by the growth of Schwann cell tumors. In all cell culture NF models the K current properties differ in tumor-derived and normal Schwann cells. Depending on the model however, the type of K channel abnormality differs. K channels appear to play a role in the proliferation of Schwann cell cultures of these disease models, because a link has been established between K current blockade and the inhibition of Schwann cell proliferation in NF1 and NF2. Differences in the proliferation response of normal Schwann cells to K channel blockers suggest that in vitro regulation of proliferation in neoplastic and normal Schwann cells is complex.

Animals↗
PubMed2002

High-level expression of receptor tyrosine kinase Ret and responsiveness to Ret-activating ligands in pheochromocytoma cell lines from neurofibromatosis knockout mice.

Pheochromocytoma cell lines derived from neurofibromatosis knockout mice express high levels of the receptor tyrosine kinase Ret, which is involved in the pathogenesis of human pheochromocytomas in hereditary multiple endocrine neoplasia syndrome type 2 (MEN2). Mouse pheochromocytoma (MPC) cells respond to the Ret-activating ligand GDNF by exhibiting Ret phosphorylation, neurite outgrowth, decreased proliferation, and altered expression of catecholamine biosynthetic enzymes. GDNF exerts similar effects on human pheochromocytoma cells in primary cultures. Ret is minimally expressed by normal mouse chromaffin cells, from which pheochromocytomas are derived. Its expression at high levels by MPC cells suggests possible relationships between two previously unrelated tumor syndromes, neurofibromatosis, and MEN2. The responsiveness of these cells to GDNF suggests that they may be a valuable new model for neurobiology.

Animals↗
PubMed1989

Cytogenetic and in situ DNA-hybridization studies in intracranial tumors of a patient with central neurofibromatosis.

We have studied a meningioma and an acoustic neurinoma of a patient with central neurofibromatosis. In the meningioma cells, one chromosome 22 was replaced by an almost metacentric, bisatellited marker chromosome that appeared monocentric after CBG-staining. In situ hybridization with a chromosome 22 centromere specific DNA probe (p22hom48.4) revealed specific signals in the pericentromeric region of the marker chromosome, indicating the presence of at least the short arm and the centromere of chromosome 22. The pericentromeric localization of the hybridization signals suggest the marker consists of an isoformation of the short arm of chromosome 22, resulting in a monosomy for the long arm of chromosome 22. In contrast to these findings in meningioma cells, no chromosomal abnormality could be detected in acoustic neurinoma cells. Our findings provide further evidence that loss of genetic material on the long arm of chromosome 22 is associated with the development of central neurofibromatosis.

Brain Neoplasms↗
PubMed1995

Dysembryoplastic neuroepithelial tumors in two children with neurofibromatosis type 1.

Dysembryoplastic neuroepithelial tumors (DNT) occur mainly in children and are always clinically associated with intractable complex partial seizures. In the first report, which included 39 cases, the patients had no neurological deficit and no stigmata of phacomatosis. In contrast, we observed a DNT in 2 children with a neurofibromatosis type 1. The first patient developed intractable complex partial seizures at age 9 years and was operated at the age of 13 years. Neuroimaging study showed multifocal involvement with three separated lesions in the frontal, parietal and temporal lobes. The second patient was a 16-year-old boy with 5-year history of severe and refractory epilepsy. Magnetic resonance imaging identified a right temporal lesion and the patient underwent a right temporal lobectomy. This unusual association of two cases of DNT with neurofibromatosis type 1 raises the question of whether this association is specific or fortuitous.

Adolescent↗
PubMed1995

Percutaneous transluminal renal angioplasty in neurofibromatosis.

A 9-year-old boy with hypertension was found to have neurofibromatosis associated with stenosis of the right renal artery. Percutaneous transluminal angioplasty (PTA) was performed. Immediately post angioplasty angiography showed that the stenosis persisted, but over the next few days his blood pressure rapidly decreased and remained well controlled even when treatment was discontinued. The captopril stimulation test, performed after PTA, confirmed the return of plasma renin activity to normal values. A digital subtraction aortogram, performed 2.5 years after PTA, was unchanged. His blood pressure remained persistently normal, without anti-hypertensive agents. Based on these results, PTA is suggested as the first step in correcting renal artery stenosis due to neurofibromatosis. A complete anatomical resolution of the stenosis is probably not required since slight improvements in the renal artery lumen may be accompanied by important functional improvement.

Angioplasty, Balloon↗
PubMed1995

Small ileal neurofibroma causing intussusception in a non-neurofibromatosis patient.

Neurofibromas in the small intestine are usually accompanied by von Recklinghausen's disease (neurofibromatosis), and usually originate in the intramuscular plexus of Auerbach. We present here a solitary neurofibroma, which caused an ileocolic intussusception, originating in the submucosal plexus of Meissner in a non-neurofibromatosis patient. To our knowledge, there is no previous report of a neurofibroma originating in the plexus of Meissner. This condition was clearly confirmed by macroscopic and microscopic evaluation.

Adult↗
PubMed2000

[Bilateral segmental neurofibromatosis simulating epidermal nevus].

Neurofibromatosis is a neuroectodermal systemic disease. A rare variant of this condition is bilateral segmental neurofibromatosis. A 29-year-old man presented with bilateral papillomatous plaques in the lumbar dermatomes. Clinically, the lesions were very similar to an epidermal nevus but histologic examination revealed superficial neurofibromas. Family history, ophthalmologic and neurologic investigations were unremarkable. The unusual morphologic presentation of bilateral segmental neurofibromas in this case points to the wide clinical spectrum of the disease and the significance of histologic examination in systematic nevoid lesions.

Adult↗
PubMed2006

[Isolated neurofibromatosis of the urinary bladder. A rare cause of recurrent cystitis].

Neurofibromas of the urinary bladder occur as isolated phenomena or as part of generalized neurofibromatosis or von Recklinghausen's disease. This benign mesenchymal tumor can be the cause of subvesical obstruction, hematuria or chronic cystitis. The lesion is rare. Our case of isolated extended neurofibromatosis of the urinary bladder was diagnosed in a 19-year-old girl with an 8-year history of chronic cystitis. Two transurethral resections were successful in relieving symptoms. Possible further therapy was delayed because of the patient's desire for children.

Adult↗
PubMed2000

Deep-seated segmental neurofibromatosis without café au lait spots.

Segmental neurofibromatosis is a rare disease characterized by neurofibromas with or without café au lait spots localized to one segment of the body. The majority of reported cases have had cutaneous neurofibromas, and patients with deep involvement have rarely been described. We report on two patients with deep-seated segmental plexiform neurofibromatosis and review the literature. All reviewed cases including the present two had no café au lait spots, axillary freckling, Lisch nodules, family history or malignant progression of disease. Differential diagnoses from neuro-fibromatosis 1 (von Recklinghausen disease) and malignant peripheral nerve sheath tumor are important for genetic counseling and avoiding overtreatment.

Adult↗
PubMedDate not supplied

Spontaneous rupture of the hepatic artery in a patient with type 1 neurofibromatosis treated by embolization: a case report.

We report the case of a 48-year-old man with neurofibromatosis presenting with sudden-onset abdominal pain, profound hypotension, and a drop in hemoglobin. CT scan demonstrated a massive hematoma within the right lobe of the liver with rupture into the peritoneal cavity. Angiography demonstrated diffuse abnormalities of the hepatic circulation with fusifom, ectatic, and stenotic segments. Acute extravasation from a peripheral branch of the right hepatic artery was identified and successfully embolized with subsequent hemodynamic stabilization of the patient. To the best of our knowledge this is the first case report of this kind in a patient with type I neurofibromatosis.

Abdominal Pain↗
PubMed2005

Neurofibromatosis as a cause of multiple coronary aneurysms.

Neurofibromatosis is a rare cause of coronary aneurysm. We present a case of multiple coronary artery aneurysms in a patient with neurofibromatosis. Coronary angiography was performed because of postmyocardial infarction angina. Coronary angiography revealed multiple coronary aneurysms in the left anterior descending and circumflex arteries, and diffuse irregularities in the right coronary artery. None of the coronary arteries showed critical stenosis. The patient was successfully managed with aspirin, clopidogrel, and beta-blocker therapy.

Adrenergic beta-Antagonists↗
PubMed2005

Aneurysm of the popliteal artery in neurofibromatosis.

The neurofibromatoses are a heterogeneous set of genetic disorders having clinical manifestations that involve the skin, the nervous system, or both. In addition, the disease can be confounded by a broad spectrum of complications, such as various kinds of osseous lesion, vascular lesions, aqueduct stenosis, optic glioma, and learning disabilities. Neurofibromatosis results in vascular involvement in approximately 10% of cases. Stenotic lesions predominate, but aneurysms have been documented as well. Rarely noted, however, have been peripheral aneurysms. In this report, we discuss the case of a 66-year-old woman with type 1 neurofibromatosis and a popliteal artery aneurysm who was operated upon because of threatened limb ischemia. Histological findings confirmed neurofibromatous invasion of the vessel wall.

Aged↗
PubMedDate not supplied

The "pseudo-CSF" signal of orbital optic glioma on magnetic resonance imaging: a signature of neurofibromatosis.

A five-and-a-half-year-old boy with neurofibromatosis had bilateral orbital optic gliomas visible on magnetic resonance imaging. Both tumors displayed a double-intensity signal characterized by a circumferential area of CSF-intensity tissue surrounding and sharply delimited from a central linear core of opposite signal intensity. The peripheral CSF-intensity signal in orbital optic glioma correlates with the histopathological finding of perineural arachnoidal gliomatosis and serves as a neuroradiologic marker for neurofibromatosis.

Child, Preschool↗
PubMed2006

Neurofibromatosis of the esophagus.

There have been previous reports suggesting an association between von Recklinghausen's neurofibromatosis and esophageal dysmotility. We report the first case of true Recklinghausen's neurofibromatosis of the esophagus leading to end-stage pseudoachalasia. The diagnosis and management of this condition is discussed together with the pathogenesis and pathology of this rare entity.

Deglutition Disorders↗
PubMed2003

The surgical management of childhood orbito-temporal neurofibromatosis.

PURPOSE: (1) To describe the natural history, changing manifestations and new signs of orbito-temporal neurofibromatosis (NF) during childhood and puberty. (2) To describe the surgical treatment and recommend guidelines for management of this condition in children compared to adults.Methods. Retrospective case note and serial photographic review. RESULTS: There were 9 patients (5M, 4F) with orbito-temporal NF who were children (<16 years) at the time of first presentation with a minimum of 5 years follow up. All the patients had unilateral periorbital neurofibromatosis with blepharoptosis, orbital enlargement and hypoglobus. All nine patients underwent blepharoptosis surgery. Eight patients underwent neurofibroma debulking (and lid shortening) and lateral canthal reattachment. Three had enucleation of their blind eyes. Seven patients had two or more operations for their orbito-palpebral deformities. New signs included conjunctival and lacrimal gland infiltration with a secondary dry eye. CONCLUSION: Blepharoptosis surgery is indicated if the visual axis is compromised and there is a chance of limiting amblyopia. Definitive surgery for appearance is best delayed until the age of 18 years, or when the disease progression has stabilised, unless there are compelling social reasons for earlier surgery.

Adolescent↗
PubMed1996

Neurofibromatosis with involvement of the prostate gland.

Urologic manifestations of neurofibromatosis type 1 are rare. The most common urologic area of involvement has been the urinary bladder. Prostate involvement in generalized neurofibromatosis has been noted previously in only 10 patients, 3 of whom were adults. Of these 3, 1 had a neurofibroma, 1 had a malignant schwannoma, and 1 patient died before tissue diagnosis could be obtained. The patient discussed in this report is the second known adult patient with biopsy-proven neurofibroma of the prostate gland. In addition, this is the first reported use of endorectal magnetic resonance imaging of the prostate to localize and specify the extent of neurofibromas in these patients.

Adult↗
PubMed2004

Neurofibromatosis with gastrointestinal stromal tumors: insights into the association.

The frequent association of stromal tumors with neurofobromatosis raises high suspicion of a possible correlation between the two entities. The aim of this study was to analyze clinicopathologic features of patients with concomitant neurofibromatosis and gastrointestinal stromal tumors and to discuss the molecular basis for their possible pathogenesis. Detailed information about clinical presentation, histology, immunostains, polymerase chain reaction amplification, and sequencing in three of our own cases was obtained. Stromal tumors presented with abdominal pain in one case and hemorrhage in another. One patient underwent surgery for malignant transformation of neurofibroma and stromal tumors were found incidentally. Stromal tumors were consistently positive for CD117, while the malignant peripheral sheath tumor was not. Mutation in the KIT juxtamembrane domain was found in one case. In this respect, some stromal tumors lack demonstrable KIT mutations but KIT remains activated. We reasoned that other mechanisms, like the Ras pathway involved in neurofibromatosis type 1, might play a role in KIT activation.

Adult↗