[Giant thoracolumbar synovial cyst: case report]. / Synovialome géant thoracolombaire: un cas.

METHODS: A case report of a giant thoracolumbar synovial cyst is presented. RESULTS: A 74-year-old woman presented with a chronic lumbar pain associated with pain in the left leg. MR imaging showed a voluminous extradural cyst extending from T12 to L2. The cyst was surgically removed entirely. Microscopic examination revealed a synovial cyst. CONCLUSIONS: In spite of a careful review of the literature, no other description of a giant thoracolumbar synovial cyst developed on three metameric levels was found. The diagnosis was made with a MRI scan combined with microscopic examination. The pathogenesis and therapeutic strategy are discussed.

[Intramedullary tumors. Results of a national investigation in private neurosurgery]. / Les tumeurs intramédullaires. Résultat d'une enquête nationale en neurochirurgie libérale.

UNLABELLED: The frequency of intramedullary tumors is 0.5 cases per year for 100,000 inhabitants. The study reported herein was a retrospective study conducted from January 1985 to September 2007. MATERIAL: Seventy-nine cases were distributed in the following manner: ependymomas, 38; astrocytomas, 22; oligodendrogliomas, four; gangliogliomas, two; hemangioblastomas, 10 (nine sporadic cases and one case of Von Hippel-Lindau disease); primitive melanoma, one; and intramedullary neurinomas, two. Three patients were lost to follow-up and 10 patients died. METHOD: All patients were explored using MRI and were operated using a microsurgical technique. Tumor removal was complete in the cases of ependymoma and hemangioblastoma and subtotal in the cases of astrocytoma. RESULTS: Ependymoma: 38 cases with three cases of ependymoblastoma. Mean age: 47 years (range, 17-74 years); 17 males and 21 females. Diagnostic delay: less than one year, 11; one year, 15 cases; two years, nine cases; three years, three cases. Seven recurrences with one 35 years after a prior removal. Localizations: cervical and cervicodorsal, 19; dorsal, ten; dorsolumbar, seven; holomedullary, one. Number of levels concerned: 5-12 (with the cysts associated). Mean follow-up was 10 years (range, two months to 35 years). Patients stabilized, 19; worse, six; improved, nine. Patients deceased: four, one by suicide, three cases of ependymoblastoma (survival, seven months). Astrocytomas: 22 cases, with 14 cases of astrocytoma, two pilocytic astrocytoma, four malignant astrocytoma, and two glioblastoma. Mean age: 44 years (range, 22-73 years); 14 males and eight females. Diagnostic delay: malignant tumors, one to nine months; low grades; three to six years (range, eight months to 25 years). Number of levels concerned: two to eight. Mean follow-up: seven years (range, six months to 10 years). Stabilized patients: 13; worse, five; deaths, four. Oligodendroglioma: four cases. Mean age: 58 years; two males and two females. Diagnostic delay: 10months. Localization: cervical, three; dorsal, one. Oligodendroglioma A, two; B, two. Results: two cases stabilized, one case with recurrence, and one patient deceased. Ganglioglioma: two. Both cases were associated with scoliosis. Recurrence in the eighth month and two years for the second case. One patient died. Hemangioblastoma: 10 cases, nine sporadic and one case of Von Hippel-Lindau disease. Nine cervical localizations, one on the medulla cone. Mean age: 45 years (range, 11-54 years); eight males and two females. Total removal in nine cases. One case of recurrence seven years after a prior surgery and operated a second time with no recurrence after 10 years of follow-up. Intramedullary neurinomas: two cases with a total removal and 15 years of follow-up. Primitive melanoma: one case with mediothoracic location. Treatment with surgery plus radiotherapy. Follow-up, seven years without recurrence. CONCLUSION: Total removal of the intramedullary tumors is a challenge. In cases of removal, the risk of worsening status is 18-19.5%. Subtotal or incomplete removal 27-40% risk of recurrence.

[Paraganglioma of the cavernous sinus. Case report]. / Paragangliome du sinus caverneux. A propos d'un cas.

A case of paraganglioma arising from the cavernous area is presented. A 51-year-old woman presented with a parasellar mass causing decreased visual acuity, oculomotor nerve paresis and retro-orbital headaches without endocrinological dysfunction. Diagnosis was confirmed by histological appearance and electron microscopy. The patient was treated with surgery followed by radiation therapy consisting of 45 Gy. The clinicopathological features and the possible pathogenesis are discussed.

Solution structure of the Ras binding domain of the protein kinase Byr2 from Schizosaccharomyces pombe.

BACKGROUND: After activation, small GTPases such as Ras transfer the incoming signal to effectors by specifically interacting with the binding domain of these proteins. Structural details of the binding domain of different effectors determine which pathway is predominantly activated. Byr2 from fission yeast is a functional homolog of Raf, which is the direct downstream target of Ras in mammalians that initiates a protein kinase cascade. The amino acid sequence of Byr2's Ras binding domain is only weakly related to that of Raf, and Byr2's three-dimensional structure is unknown. RESULTS: We have solved the 3D structure of the Ras binding domain of Byr2 (Byr2RBD) from Schizosaccharomyces pombe in solution. The structure consists of three alpha helices and a mixed five-stranded beta pleated sheet arranged in the topology betabetaalphabetabetaalphabetaalpha with the first seven canonic secondary structure elements forming a ubiquitin superfold. 15N-(1)H-TROSY-HSQC spectroscopy of the complex of Byr2RBD with Ras*Mg(2+)*GppNHp reveals that the first and second beta strands and the first alpha helix of Byr2 are mainly involved in the protein-protein interaction as observed in other Ras binding domains. Although the putative interaction site of H-Ras from human and Ras1 from S. pombe are identical in sequence, binding to Byr2 leads to small but significant differences in the NMR spectra, indicating a slightly different binding mode. CONCLUSIONS: The ubiquitin superfold appears to be the general structural motif for Ras binding domains even in cases with vanishing sequence identity. However, details of the 3D structure and the interacting interface are different, thereby determining the specifity of the recognition of Ras and Ras-related proteins.

The Ras-Byr2RBD complex: structural basis for Ras effector recognition in yeast.

BACKGROUND: The small GTP binding protein Ras has important roles in cellular growth and differentiation. Mutant Ras is permanently active and contributes to cancer development. In its activated form, Ras interacts with effector proteins, frequently initiating a kinase cascade. In the lower eukaryotic Schizosaccharomyces pombe, Byr2 kinase represents a Ras target that in terms of signal-transduction hierarchy can be considered a homolog of mammalian Raf-kinase. The activation mechanism of protein kinases by Ras is not understood, and there is no detailed structural information about Ras binding domains (RBDs) in nonmammalian organisms. RESULTS: The crystal structure of the Ras-Byr2RBD complex at 3 A resolution shows a complex architecture similar to that observed in mammalian homologous systems, with an interprotein beta sheet stabilized by predominantly polar interactions between the interacting components. The C-terminal half of the Ras switch I region contains most of the contact anchors, while on the Byr2 side, a number of residues from topologically distinct regions are involved in complex stabilization. A C-terminal helical segment, which is not present in the known mammalian homologous systems and which is part of the auto-inhibitory region, has an additional binding site outside the switch I region. CONCLUSIONS: The structure of the Ras-Byr2 complex confirms the Ras binding module as a communication element mediating Ras-effector interactions; the Ras-Byr2 complex is also conserved in a lower eukaryotic system like yeast, which is in contrast to other small GTPase families. The extra helical segment might be involved in kinase activation.

Influence of acyl chain fluidity on the lipopolysaccharide-induced activation of complement.

Lipopolysaccharides (LPSs, endotoxins) are the major amphiphilic constituents of the outer leaflet of the outer membrane of Gram-negative bacteria. They are known to activate the complement cascade to form lytic membrane pores. Here, we study the influence of the fluidity of the acyl chains of LPSs and lipid As on the formation of lytic pores. To this end, we have performed electrical measurements on asymmetric planar endotoxin/phospholipid bilayers as a reconstitution model of the outer membrane using two deep rough mutant LPSs (from Escherichia coli strains WBB01 and WBB25) and two lipid As (from E. coli WBB25 and Rhodobacter sphaeroides). The two LPSs and the two lipid As each differ in their acylation pattern which is correlated with the fluidity. The addition of human serum to the endotoxin side of the bilayers led to the formation of membrane pores, and pore formation correlated in each case with acyl chain fluidity, i.e. time required for the first lytic pore to be formed was shorter for the more fluid endotoxin. Furthermore, in the case of LPSs, the activation rate was higher for the more fluid membrane and the respective bacteria had a higher susceptibility to the growth inhibitory action of serum.

Thermodynamics of Ras/effector and Cdc42/effector interactions probed by isothermal titration calorimetry.

Proliferation, differentiation, and morphology of eucaryotic cells is regulated by a large network of signaling molecules. Among the major players are members of the Ras and Rho/Rac subfamilies of small GTPases that bind to different sets of effector proteins. Recognition of multiple effectors is important for communicating signals into different pathways, leading to the question of how an individual GTPase achieves tight binding to diverse targets. To understand the observed specificity, detailed information about binding energetics is expected to complement the information gained from the three-dimensional structures of GTPase/effector protein complexes. Here, the thermodynamics of the interaction of four closely related members of the Ras subfamily with four different effectors and, additionally, the more distantly related Cdc42/WASP couple were quantified by means of isothermal titration calorimetry. The heat capacity changes upon complex formation were rationalized in light of the GTPase/effector complex structures. Changes in enthalpy, entropy, and heat capacity of association with various Ras proteins are similar for the same effector. In contrast, although the structures of the Ras-binding domains are similar, the thermodynamics of the Ras/Raf and Ras/Ral guanine nucleotide dissociation stimulator interactions are quite different. The energy profile of the Cdc42/WASP interaction is similar to Ras/Ral guanine nucleotide dissociation stimulator, despite largely different structures and interface areas of the complexes. Water molecules in the interface cannot fully account for the observed discrepancy but may explain the large range of Ras/effector binding specificity. The differences in the thermodynamic parameters, particularly the entropy changes, could help in the design of effector-specific inhibitors that selectively block a single pathway.

[Painful sciatic rubbing caused by benign synovioma of the spinal joints. Apropos of 4 cases]. / Conflits mécaniques sciatalgiques par synovialome bénin des articulations rachidiennes. A propos de quatre cas.

Synovioma, a benign neoplasm arising from pigmented villonodular synovium or synovitis, is uncommon. It involves the tendons and joints of the finger, ankle and foot. In this study four cases of villonodular synovioma of spinal joints are reported. The authors studied 555 cases of patients operated for sciatica due to herniated disk. Histopathology showed that in four out of 555 cases sciatica was found to be due to synoviomas of the spinal joints. The patients, three women and one man, were between 54 and 70 years of age and each had had a long history of low back pain with episodes of sciatica. Clinical evaluation at the time of surgery showed moderate severity of signs and symptoms. Roentgenographic studies of all four cases revealed osteoarthritic changes of vertebral apophyses, with two cases of spondylolisthesis. The pathogenesis of synovioma remains controversial and its histopathological characterization -hyperplasia VS/true tumours- has not yet been determined. It is possible that the number of recorded cases of sciatica due to synoviomas is small because surgical and pathological studies in patients with sciatica associated with osteoarthritic changes have not been adequately performed. Surgery consists of a large resection of the capsule and ligament including resection of intraspinal extension. Because this study involves only four cases, the first of which occurred in 1977, the possibility of recurrence cannot be evaluated.

[Management of the non traumatic dissecting aneurysm of the cervical portion of the internal carotid artery (author's transl)]. / L'anévrysme disséquant non traumatique de la carotide interne cervicale. Conduite à tenir.

The spontaneous dissecting aneurysms of the internal cervical carotid artery are renowned unusual, as about fifty cases only are reported in the literature. About 18 cases of dissecting aneurysms, 5 of which operated on and 13 clinically and radiologically followed, the authors try to draw a management. This one is resolutely conservative because: 1. It is possible to expect the spontaneous evolution according to the radiological form of the dissection which becomes in the great majority of cases toward repermeability. 2. The exceptional cases evolving to the thrombosis can later have an extra-intracranial anastomosis. 3. The cases justifying a direct surgical approach are exceptional and the operatory decision is easily taken according to the radiological aspect. On the whole, this pathology seems less unusual than the literature leads to suppose and the spontaneous evolution is worth to be well known because it conditions the management.

[Primary "mycotic" aneurysm of the common carotid artery. Report of one case (author's transl)]. / Anévrysme "mycotique" primitif de la carotide primitive. A propos d'un cas.

Primary mycotic aneurysm of the common carotid artery is exceptional. The clinical characteristics are dominated by the absence of a detectable infectious cause, by the macroscopic, nonsuppurative aspect and the sudden increase in volume requiring emergency operation. The treatment of these aneurysms is surgical, but little known owing to the rareness of these cases. Reconstructive surgery gives satisfactory results. Its details are discussed in relation to the operative appearance.

[Value of extra-intracranial anastomosis: based on a series of 65 cases]. / Réflexions sur les anastomoses extra-intracraniennes: a propos d'une série de 65 cas.

The authors describe the results obtained in a series of 65 patients following extra-intracranial cortical anastomosis. The best indications for this procedure are transitory ischemic accidents which cannot be approached by the direct cervical route. Cases of prolonged or definitive vascular accidents and more especially localized lesions also gave valuable results but these depend upon the condition of the cerebral parenchyma which must be carefully evaluated.