Two level Anterior Lumbar Interbody Fusion (ALIF) in a patient with a rare vascular malformation, a duplication of the inferior vena cava.

BACKGROUND: Anterior Lumbar Interbody Fusion is now a well-established procedure to treat degenerative lumbar disease. This approach has its own risks and each spine surgeon must understand the pitfalls that can be encountered when dealing with an anatomy variation of the vessels in order to be able to perform the safest possible procedure. CASE DESCRIPTION: We report the case of a 48 years old man with a rare vascular anatomy variation undergoing a two-levels L4-L5 and L5-S1 ALIF procedure through a right-sided retroperitoneal approach. The preoperative imaging planning revealed a duplication of the Inferior Vena Cava (IVC) located on each side of the aorta. CONCLUSION: Preoperative Imaging evaluation and a detailed knowledge of the anatomy is the key of a safe and successful procedure as any variation can complicate the anterior approach. We believe that teaming up with a vascular surgeon for junior surgeons during the first anterior procedures and especially in the context of anatomical variation is recommended.

Acute isodense subdural hematoma on computed tomography scan--diagnostic and therapeutic trap: a case report.

BACKGROUND: Post-traumatic acute subdural hematomas generally appear hyperdense on a computed tomography scan. In the hyperacute stage, a subdural hematoma in rare cases appears heterogeneous with isodense images. This can pose a diagnostic problem and compromise patient care. Here we report a case of an isodense subdural hematoma and its management. CASE PRESENTATION: We report the case of a 59-year-old white European man who had a serious head injury with an acute subdural hematoma. The trauma was also responsible for blood loss and hemostasis disorders. A cerebral computed tomography scan revealed an isodense subdural hematoma. Our intervention confirmed that it was an acute hematoma. CONCLUSIONS: This unusual isodense appearance is due to anemia. It can be the cause of misdiagnosis and incorrect treatment choices.

[Orbital tumors. Neurosurgical activity]. / Tumeurs orbitaires. Activité neurochirurgicale.

In this chapter, we report the results of orbital tumor management in a few neurosurgical departments and compare it to a Paris neurosurgical department that has developed a close relation with an ophthalmological department. These departments' activity is quite low, treating mainly sphenoorbital meningiomas. Other tumor groups are unequally and sporadically managed.

The nonhelical tail domain of keratin 14 promotes filament bundling and enhances the mechanical properties of keratin intermediate filaments in vitro.

Keratin filaments arise from the copolymerization of type I and II sequences, and form a pancytoplasmic network that provides vital mechanical support to epithelial cells. Keratins 5 and 14 are expressed as a pair in basal cells of stratified epithelia, where they occur as bundled arrays of filaments. In vitro, bundles of K5-K14 filaments can be induced in the absence of cross-linkers, and exhibit enhanced resistance to mechanical strain. This property is not exhibited by copolymers of K5 and tailless K14, in which the nonhelical tail domain has been removed, or copolymers of K5 and K19, a type I keratin featuring a short tail domain. The purified K14 tail domain binds keratin filaments in vitro with specificity (kD approximately 2 microM). When transiently expressed in cultured cells, the K14 tail domain associates with endogenous keratin filaments. Utilization of the K14 tail domain as a bait in a yeast two-hybrid screen pulls out type I keratin sequences from a skin cDNA library. These data suggest that the tail domain of K14 contributes to the ability of K5-K14 filaments to self-organize into large bundles showing enhanced mechanical resilience in vitro.

The 'ins' and 'outs' of intermediate filament organization.

A major function shared by several types of cytoplasmic intermediate filaments (IFs) is to stabilize cellular architecture against the mechanical forces it is subjected to. As for other fibrous cytoskeletal arrays, a crucial determinant of this function is the spatial organization of IFs in the cytoplasm. However, very few crossbridging proteins are specific for IFs - most IF-associated proteins known to exert a structural role act to tether IFs to other major cytoskeletal elements, such as F-actin, microtubules or adhesion complexes. In addition, IFs are endowed with the ability to participate in their own organization. This intriguing property is probably connected to the unusual degree of sequence diversity and sequence-specific regulation that characterize IF genes and their proteins. This dependence upon a combination of extrinsic and intrinsic determinants contributes to distinguish IFs from other fibrous cytoskeletal polymers and is key to their function.

Is the hippocampus a Kalman filter?

Based on a large body of neurophysiological, neuroanatomical, and behavioral data, it has been suggested that the hippocampal formation serves as a spatial learning and localization system. This spatial representation is metric in nature and arises as a result of associations between sensory inputs and dead-reckoning information generated by the animal. However, despite the fact that these two information streams provide uncertain information (e.g., recognition errors, dead-reckoning drifts, etc.), the hippocampal computational models suggested to date have not explicitly addressed information fusion from erroneous sources. In this paper we develop a computational model of hippocampal spatial learning and relate its functioning to a probabilistic tool used for uncertain sensory fusion in robots: the Kalman filter. This parallel allows us to derive statistically optimal update expressions for the localization performed by our computational model.

Cytoskeleton: missing links found?

The quest for the function of BPAG1, a major hemidesmosomal protein of skin keratinocytes, has led to the discovery of a group of protein isoforms derived from the same genomic locus that are involved in organizing and integrating cytoskeletal networks in sensory neurons.

[Neuronal intermediate filament proteins]. / Les protéines de filaments intermédiaires neuronales.

The characteristics of the seven intermediate filament proteins expressed during the development of neurons are reviewed. The most extensively studied have been neurofilament proteins (NFP) and peripherin. The relative plasticity of the peripherin network can account for its possible role during development when the axons of the neurons in which this protein is expressed have to find their targets crossing a non-neural environment probably in answer to signals from this environment and from their respective targets. Peripherin may assume a similar role when axons regenerate. NFP are considered as maintaining the axonal caliber, thus ensuring a normal axonal transport. Their network is highly disrupted in several diseases, particularly in motor neuron diseases. Mice transgenic for human NFP or in which mouse NFP are overexpressed have been obtained and are considered as animal models for these diseases.

Aggregation of a subpopulation of vimentin filaments in cultured human skin fibroblasts derived from patients with giant axonal neuropathy.

Giant axonal neuropathy (GAN) is a generalized disorder of intermediate filament networks which results in the formation of an ovoid aggregate in a large variety of cell types. We investigated the cytoskeletal organization of cultured skin fibroblasts derived from three GAN patients by indirect immunofluorescence, confocal, and electron microscopy. Whereas the organization of microfilaments seemed normal, the microtubule network appeared disorganized and tangled. The organization of the intermediate filament network, composed of vimentin, was probed with three antibodies directed against different epitopes: two vimentin-specific antibodies, a monoclonal antibody (mAb V9) and a polyclonal antibody, and a serum specific for all type III IFPs (PI serum). These experiments showed that 20% of cultured skin fibroblasts from GAN patients have a vimentin aggregate composed of densely packed filaments which coexists with a well-organized vimentin network. After depolymerization of microtubules with nocodazole, all fibroblasts from GAN patients contained a vimentin aggregate which seemed to arise from a subpopulation of vimentin filaments normally integrated in the vimentin network. Such aggregates were never observed in any condition in control fibroblasts. Moreover, the ultrastructural analysis of GAN cells revealed the presence of swollen mitochondria. We suggest that GAN may be due to a defect in a factor which stabilizes cytoplasmic intermediate filament networks, and we speculate on its identification and properties.

Peripherin and neurofilaments: expression and role during neural development.

This review focuses attention on the expression of peripherin and the low-molecular mass neurofilament protein during development, as well as on recent results concerning the roles of these neuronal proteins. Peripherin is the only type III intermediate filament that has been shown to be expressed in neurons but exclusively in motor, sensory and sympathetic neurons; moreover, it is co-expressed with neurofilament proteins (NFP). Clearly, peripherin is expressed concomitantly with axonal growth during development, and its synthesis appears necessary to axonal regeneration in the adult. As to NFP, they are presumed to maintain the axonal diameter and thereby ensure a normal conduction velocity. In many neuropathies, either occurring in man or provoked by different means in animals, the neurofilament network is disrupted thus giving rise to bundles of filaments in perikarya or along axons; consequently, the axonal transport is impaired. The possible significance of the overexpression of NFP is discussed.

[Portal hypertension: a rare cause of hematuria]. / L'hypertension portale: une cause rare d'hématurie.

A patient with undiagnosed cirrhosis presented with massive haematuria 16 years after augmentation colonoplasty. Portal hypertension (PHT) was responsible for a portocaval collateral circulation with vesical varices detected by low pressure endoscopy performed between episodes of haematuria. A very similar case was published in 1991. Surgical haemostatis with partial or total resection of the colonoplasty was only temporarily effective in our patient, who subsequently underwent liver transplantation due to repeated episodes of hepatic encephalopathy. No recurrence of haematuria was observed six years after the diversion. This rare cause of haematuria must be considered in view of the widespread use of intestinal conduits in urology: a dozen cases have been reported after transileal cutaneous ureterostomy, occurring an average of 3 years after the operation. Direct treatment of the varices, either by surgical devascularisation or resection or be endoscopic laser sclerosis or coagulation, is only temporarily effective. Treatment of the PHT appears to be the most effective measure in the long term: beta-blockers administered in the absence of episodes of haematuria or portal by-pass surgery in the case of failure.

[Listeria monocytogenes liver abscess. In a diabetic patient]. / Abcès du foie à Listeria monocytogenes. Chez une malade diabétique.

Most liver abscesses are caused by Enterobacteriaceae, sometimes associated with anaerobes. Listeriosis is an exceptional cause of liver abscess, usually in a context of disseminated infections. We report the case of a diabetic woman who had liver abscess due to Listeria monocytogenes. The organism was isolated after guided needle aspiration, and there was no other site of infection. The course of the disease gradually moved towards recovery under an antibiotic therapy that was based on sensitivity tests. A search for immunodeficiency proved negative. A review of the literature showed that the rare cases of listerial liver abscess share a common factor, diabetes mellitus, the importance of which has not yet been noticed.

[Interferon alpha-2a treatment of 26 patients with chronic non-A non-B hepatitis. Predictive factors of response]. / Traitement par l'interféron alpha-2a de 26 cas d'hépatites chroniques non A-non B. Etude des facteurs prédictifs de réponse.

The type and predicting factors of response to alpha interferon therapy have been studied in 26 patients with chronic non-A non-B hepatitis. Interferon was administered three times weekly during 6 months at a dose of 3 millions units/day. Eleven patients (42 percent) had serum alanine aminotransferase levels below 1.5 times the upper limit of normal range at the end of treatment. Only eight (31 percent) patients had persistent normalization of seric alanine aminotransferase value, 6 months after the end of the interferon treatment. The main factors involved in the response to therapy were age, apparent duration of the disease, and mode of contamination: patients who responded to interferon were younger, had a shorter duration of hepatitis and a parenterally transmitted disease.

[Spontaneous esophageal perforation. Radiological diagnosis]. / Perforation oesophagienne spontanée. Diagnostic radiologique.

Esophageal perforations are rare and usually occur after instrumentation. We relate here a case unsuspected spontaneous esophageal perforation. Computed chest tomography firstly showed signs of mediastinal abscess. Secondary barium meal confirmed the diagnosis.