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Chemical cross-linking of ultrahigh molecular weight polyethylene (UHMWPE) using an organic peroxide followed by high temperature melting results in a large increase in toughness accompanied by a decrease in cross-link density, which, surprisingly does not compromise the wear resistance. We compared the mechanical properties and wear behavior of a vitamin E blended, chemically cross-linked and high temperature melted UHMWPE produced by ram extrusion (PRX HTM) to those measured with the clinically available 100-kGy irradiated and melted UHMWPE (CISM 100). We also assessed the local biocompatibility of PRX-HTM in rabbit subcutaneous pouch and osteochondral defect models. The ultimate tensile strength and pin-on-disc wear rate were similar to CISM 100; whereas the elongation-at-break and impact toughness were much higher with PRX-HTM. The stress intensity factor range at crack inception was also higher with PRX-HTM. Accelerated aging did not result in any measurable oxidation or changes in mechanical properties. Hip simulator wear rate of acetabular liners made with PRX-HTM was 0.3 ± 0.4 mg/million-cycle, similar to that reported for CISM 100 liners. The wear particles were largely spherical with a number-averaged particle size of 0.95 μm with ~75% of particles below 1 μm. The subcutaneous and osteochondral rabbit implantations showed no histological differences between PRX-HTM and the control CISM 100. Pre-clinical wear, mechanical, and biocompatibility testing of PRX HTM showed feasibility for the use of this material as a total joint arthroplasty implant bearing surface. This process has the potential of eliminating the additional step of radiation cross-linking by combining consolidation and cross-linking while improving toughness. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1945-1952, 2019.

A previously healthy 6-year-old boy was admitted to hospital with hypotonia and hyposthenia of lower limbs. Electromyography and slow motor nerve conduction velocity test identified a lower limb acute motor axonal neuropathy. Brain and spinal cord magnetic resonance imaging demonstrated multifocal cortical gray matter lesions in both cerebral hemispheres consistent with gray matter acute disseminated encephalitis otherwise with viral/Mycoplasma pneumoniae encephalitis, and signs of involvement of anterior nerve roots of the cauda equina consistent with Guillain-Barré syndrome. The patient resulted negative to routinely bacterial and viral investigations but positive to human parechovirus that sequence analyses confirmed as type 6. Intravenous immunoglobulins and methylprednisolone treatment were administered but did not relieve the symptoms of Guillain-Barré syndrome. The disease improved gradually over the next 3-month follow-up with a complete remission of both central and peripheral nervous system symptoms.

Background and purpose Ataxia-telangiectasia (A-T) is a rare neurodegenerative disease, due to A-T mutated (ATM) gene mutations, which typically presents with signs of progressive neurological dysfunction, cerebellar ataxia and uncoordinated movements. A-T severely affects patients' quality of life. Successful treatment options are still not available. The aim of this multicenter study, performed with a blind evaluation procedure, was to define the minimal effective dosage of oral betamethasone, thus preventing the occurrence of side effects. Methods Nine A-T patients were enrolled to receive betamethasone at increasing dosages of 0.001, 0.005 and 0.01 mg/kg/day. Neurological assessment and the evaluation of quality of life were performed through the Scale for the Assessment and Rating of Ataxia and the Italian version of the Childhood Health Assessment Questionnaire (CHAQ) at each time-point. The drug safety profile was evaluated. Patients were categorized as responders, partial responders and non-responders. Results Four of nine patients had a benefit at a dose of 0.005 mg/kg/day of oral betamethasone. Using the higher dosage, only one additional patient had a positive response. Conversely, a daily dose of 0.001 mg/kg was ineffective. A correlation between the serum adrenocorticotropic hormone levels and the clinical response was observed. Five of 30 CHAQ items improved in four patients. Conclusions These data suggest that a short-term betamethasone oral treatment, at a daily dosage of 0.005 mg/kg, is effective in some patients. Pre-existing risk factors for side effects should be taken into account before therapy.

Key points Loss-of-function mutations of the skeletal muscle ClC-1 channel cause myotonia congenita with variable phenotypes. Using patch clamp we show that F484L, located in the conducting pore, probably induces mild dominant myotonia by right-shifting the slow gating of ClC-1 channel, without exerting a dominant-negative effect on the wild-type (WT) subunit. Molecular dynamics simulations suggest that F484L affects the slow gate by increasing the frequency and the stability of H-bond formation between E232 in helix F and Y578 in helix R. Three other myotonic ClC-1 mutations are shown to produce distinct effects on channel function: L198P shifts the slow gate to positive potentials, V640G reduces channel activity, while L628P displays a WT-like behaviour (electrophysiology data only). Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function. Abstract Myotonia congenita is an inherited disease caused by loss-of-function mutations of the skeletal muscle ClC-1 chloride channel, characterized by impaired muscle relaxation after contraction and stiffness. In the present study, we provided an in-depth characterization of F484L, a mutation previously identified in dominant myotonia, in order to define the genotype–phenotype correlation, and to elucidate the contribution of this pore residue to the mechanisms of ClC-1 gating. Patch-clamp recordings showed that F484L reduced chloride currents at every tested potential and dramatically right-shifted the voltage dependence of slow gating, thus contributing to the mild clinical phenotype of affected heterozygote carriers. Unlike dominant mutations located at the dimer interface, no dominant-negative effect was observed when F484L mutant subunits were co-expressed with wild type. Molecular dynamics simulations further revealed that F484L affected the slow gate by increasing the frequency and stability of the H-bond formation between the pore residue E232 and the R helix residue Y578. In addition, using patch-clamp electrophysiology, we characterized three other myotonic ClC-1 mutations. We proved that the dominant L198P mutation in the channel pore also right-shifted the voltage dependence of slow gating, recapitulating mild myotonia. The recessive V640G mutant drastically reduced channel function, which probably accounts for myotonia. In contrast, the recessive L628P mutant produced currents very similar to wild type, suggesting that the occurrence of the compound truncating mutation (Q812X) or other muscle-specific mechanisms accounted for the severe symptoms observed in this family. Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function.

Large-diameter femoral heads are being used increasingly in total hip arthroplasty (THA) to minimize hip dislocation risk. However, recent studies have shown that conventional large heads can impinge on native soft tissues, particularly the iliopsoas, leading to activity-limiting anterior hip pain. To address this, a novel soft-tissue-friendly anatomically contoured femoral head (ACH) was developed. This paper describes the design rationale and pre-clinical testing of the ACH implant. The test results demonstrate that anatomical contouring of large-diameter femoral heads for soft-tissue relief can be accomplished without affecting dislocation resistance, femoroacetabular contact area, or wear performance in ceramic-on-polyethylene implants.

A very simple method of synthesis of goethite,alfa-FeOOH, nanowire is reported. To fabricate the nanowires, an anodiezed alumina nanoporous template (AAO) is used. AAO has pores with an average diameter of 60 nm. The synthesis is based on a self-combustion reaction of the chemical precursor (Fe(NO3)3 satured solution) which occurs inside the nanopores. The geometry of AAO determines the morphology of the nanowires and the confinement conditions in which the heat treatment determines the composition of the nanostruc- ture. The nanowires are characterized using scanning electronmicroscopy, high resolution transmission electronmicroscopy andmagne- tometry [magnetization versus applied field (M versus H)]. TEM analysis indicates that nanowires are composed of several alfa-FeOOH single crystals. The nanowires have a clear magnetic oriented structure. Fil: Londoño Calderon, Cesar Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Bilovol, Vitaliy. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Cosio Castañeda, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Pampillo, Laura Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Micheli, Sabina R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Pirota, Kleber Roberto. Universidade Estadual de Campinas; Brasil Fil: Socolovsky, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina Fil: Martinez Garcia, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina

Structured Abstract Objectives Literature is poor of data about the occlusion in children affected by neurofibromatosis type 1 (NF1). This case–control study investigated the occlusal traits in a group of children with NF1. Setting and sample population A hundred and fifteen children with NF1 were enrolled; non-NF1 controls were sequentially selected among subjects referred to the Pediatric Dentistry Department. Material and methods All patients underwent a clinical dental examination and a panoramic radiography. The following orthodontic variables were considered: molar relationship, overjet, overbite, cross-bite, scissor bite, and crowding/spacing. Results Class III molar relationship resulted significantly (p = 0.01) more common in children with NF1 than in the control group as well as the unilateral posterior cross-bite (p = 0.0017). Forty-three children with NF1 (37.3%) showed radiographic abnormalities; in one case, a plexiform neurofibroma was detected. Conclusions An early orthodontic evaluation might be planned in the management of children with NF1 to prevent or decrease the need for extensive orthodontic interventions.

Background: Radiation crosslinking reduces wear of ultra-high molecular weight polyethylene (UHMWPE), and subsequent annealing or melting increases oxidative stability. Little is known about the oxidative stability of polyethylene total joint components after in vivo service and subsequent shelf storage in air. Methods: We analyzed thirty-four surgically retrieved, radiation crosslinked acetabular liners to determine their oxidative stability after in vivo service (range, 0.5 to 84.0 months). Oxidation was determined at the time of explantation. After shelf storage in air (range, 7.0 to 72.0 months), oxidation, crosslink density, and thermal properties were determined. Oxidation of one control liner that was shelf-aged in air (for eighty-four months) was also determined. Results: At the time of explantation, all components showed minimal oxidation; however, oxidation levels increased during shelf storage, with a concomitant decrease in crosslink density and increase in crystallinity. Increasing oxidation, increasing crystallinity, and decreasing crosslink density correlated with the duration of ex vivo storage. The shelf-aged control liner showed no detectable oxidation. Conclusions: The oxidation and loss of crosslink density of the irradiated and melted UHMWPE was surprising. Two potential mechanisms that might alter the oxidative stability of UHMWPE in vivo are cyclic loading and absorption of lipids. Both of these mechanisms can generate new free radicals in UHMWPE and can initiate and propagate its oxidation. Clinical Relevance: It is not known if the ex vivo instability reported here will occur in vivo in the long term and, therefore, further investigation of surgical explants is warranted.

Wear particle-induced periprosthetic osteolysis has been a clinical problem driving the development of wear resistant ultrahigh molecular weight polyethylene (UHMWPE) for total joint replacement. Radiation crosslinking has been used to decrease wear through decreased plastic deformation; but crosslinking also reduces mechanical properties including fatigue resistance, a major factor limiting the longevity of joint implants. Reducing UHMWPE wear with minimal detriment to mechanical properties is an unaddressed need for articular bearing surface development. Here we report a novel approach to achieve this by limiting crosslinking to the articular surface. The antioxidant vitamin E reduces crosslinking efficiency in UHMWPE during irradiation with increasing concentration, thus we propose to spatially control the crosslink density distribution by controlling the vitamin E concentration profile. Surface crosslinking UHMWPE prepared using this approach had high wear resistance and decreased crosslinking in the bulk resulting in high fatigue crack propagation resistance. The interface region did not represent a weakness in the material due to the gradual change in the crosslink density. Such an implant has the potential of decreasing risk of fatigue fracture of total joint implants as well as expanding the use of UHMWPE to younger and more active patients.

Wear and delamination of conventional ultrahigh-molecular-weight polyethylene (UHMWPE) components used in total knee arthroplasty can compromise long-term performance. Radiation cross-linking and melt-annealing reduced wear and increased delamination resistance of UHMWPE. An alternative material is the alpha-tocopherol-stabilized irradiated UHMWPE (alphaTPE), with improved mechanical and fatigue properties vs irradiated and melted UHMWPE. We studied the wear and delamination resistance of alphaTPE and conventional UHMWPE (direct compression molded GUR 1050 and Himont 1900) under reciprocating unidirectional motion. Wear resistance was improved, and no delamination was observed in alphaTPE. Accelerated aging did not alter the wear and delamination behavior of alphaTPE. The GUR 1050 UHMWPE showed delamination and pitting when subjected to unidirectional reciprocating motion after accelerated aging. Himont 1900 UHMWPE showed no delamination when subjected to unidirectional reciprocating motion after accelerated aging. alpha-Tocopherol-stabilized irradiated UHMWPE is advanced for use in total knee arthroplasty due to its high resistance to wear, delamination, and oxidation.

We measured patterns of river channel migration and cutoff between 1904 and 1997 on a 160 km meandering alluvial reach of the Sacramento River by intersecting a sequential set of river channel centrelines mapped from a field survey and aerial photography. We identified approximate dates and locations of cutoffs and quantified cutoff dimensions. Twenty-seven chute and 11 partial cutoffs occurred over this 93-year time interval, with an average of one cutoff approximately every 2.5 years or 0.0029 cutoffs per kilometre per year. The average rate of lateral channel change was over the study period was 5.5 ± 0.6 m year−1 (approximately 0.02 channel widths per year) due to progressive migration and cutoff combined. An average of 5% of the total channel length moved laterally via chute cutoff at a rate of 22.1 ± 3.3 m year−1 versus 94% of channel length that moved via progressive migration at a rate of 4.7 ± 0.5 m year−1. The remaining 1% of channel length migrated via partial cutoff at a rate of 13.0 ± 2.8 m year−1. Although channel cutoff was less predominant mode of channel change than progressive migration in terms of channel length, an average of 20% of the total floodplain area change between successive centrelines was attributable to cutoffs. Peak cutoff frequency was concentrated temporally between 1964 and 1987 and was also spatially clustered in specific active sub-reaches along the valley axis over the entire study period. We hypothesize that the probability of channel cutoff is a function of both channel geometry and discharge. Bends that experienced chute cutoff displayed an average sinuosity of 1.97 ± 0.1, an average radius of curvature of 2.1 ± 0.2 channel widths and an average entrance angle of 111 ± 7°, as opposed to average values for bends migrating progressively of 1.31 ± 0.01, 2.8 ± 0.1 and 66 ± 1°, respectively. The sinuosity of Sacramento River bends experiencing chute cutoff appears to have been consistently declining from 2.25 ± 0.35 channel widths in 1904 to 1.54 ± 0.23 channel widths in 1987. We hypothesize that this trend may be due in part to the influence of land-use changes, such as the conversion of riparian forest to agriculture, on the ‘erodibility’ of bank and floodplain materials. For the post-dam flow regime (1937 on), cutoff frequency was significantly correlated with an estimate of cumulative overbank flow. Copyright © 2010 John Wiley & Sons, Ltd.

Riparian forest vegetation is widely believed to protect riverbanks from erosion, but few studies have quantified the effect of riparian vegetation removal on rates of river channel migration. Measured historical changes in a river channel centreline, combined with mapped changes in floodplain vegetation, provide an opportunity to test how riparian vegetation cover affects the erodibility of riverbanks. We analysed meander migration patterns from 1896 to 1997 for the central reach of the Sacramento River between Red Bluff and Colusa, using channel planform and vegetation cover data compiled from maps and aerial photography. We used a numerical model of meander migration to back-calculate local values for bank erodibility (i.e. the susceptibility of bank materials to erosion via lateral channel migration, normalized for variations in near-bank flow velocities due to channel curvature). A comparison of migration rates for approximately 50 years before and after the construction of Shasta dam suggests that bank migration rates and erodibility increased roughly 50%, despite significant flow regulation, as riparian floodplains were progressively converted to agriculture. A comparison of migration rates and bank erodibilities between 1949 and 1997, for reaches bordered by riparian forest versus agriculture, shows that agricultural floodplains are 80 to 150% more erodible than riparian forest floodplains. An improved understanding of the effect of floodplain vegetation on river channel migration will aid efforts to predict future patterns of meander migration for different river management and restoration scenarios. Copyright © 2004 John Wiley & Sons, Ltd.

We quantified how rates of stream channel migration in a montane meadow vary as a function of the riparian vegetation community. The South Fork of the Kern River at Monache Meadow, located in California's southern Sierra Nevada range, supports two distinct types of vegetation: a dry meadow community dominated by sagebrush and non-native grasses (xeric scrub and meadow), and a wet meadow community dominated by rushes and sedges (hydric graminoids). We measured rates of lateral stream migration for dry versus wet meadow reaches from aerial photographs spanning a 40-year period (1955–1995). While stream migration rates averaged only 0·24 ± 0·02 m a−1 in the wet meadow, the dry meadow channel migrated an average of 1·4 ± 0·3 m a−1. We used a linear model of meander migration to calculate coefficients that characterize bank migration potential, or bank erodibility, independent of channel curvature. These calculations demonstrate that, at Monache Meadow, banks without wet meadow vegetation are roughly ten times more susceptible to erosion than banks with wet meadow vegetation. Where stream bank heights consistently exceed 1 m, low water availability creates riparian habitats dominated by dry meadow vegetation. Thus, channel incision may reduce bank stability not only by increasing bank height, but also by converting banks from wet meadow to dry meadow vegetation. Copyright © 2002 John Wiley & Sons, Ltd.

We measured the effect of wet meadow vegetation on the bank strength and failure mechanics of a meandering montane meadow stream, the South Fork of the Kern River at Monache Meadow, in California's Sierra Nevada. Streambanks colonized by ‘wet’ graminoid meadow vegetation were on average five times stronger than those colonized by ‘dry’ xeric meadow and scrub vegetation. Our measurements show that strength is correlated with vegetation density indicators, including stem counts, standing biomass per unit area, and the ratio of root mass to soil mass. Rushes appear better than sedges at stabilizing coarse bar surfaces, while sedges are far more effective at stabilizing actively eroding cut banks. Wet meadow floodplain vegetation creates a composite cut bank configuration (a cohesive layer overlying cohesionless materials) that erodes via cantilever failure. Field measurements and a geotechnical model of cantilever stability show that by increasing bank strength, wet meadow vegetation increases the thickness, width, and cohesiveness of a bank cantilever, which, in turn, increases the amount of time required to undermine, detach, and remove bank failure blocks. At Monache Meadow, it takes approximately four years to produce and remove a 1 m wide wet meadow bank block. Wet meadow vegetation limits bank migration rates by increasing bank strength, altering bank failure modes, and reducing bank failure frequency. Copyright © 2002 John Wiley & Sons, Ltd.

River and stream restoration projects are increasingly numerous but rarely subjected to systematic postproject evaluation. Without conducting such evaluation and widely disseminating the results, lessons will not be learned from successes and failures, and the field of river restoration cannot advance. Postproject evaluation must be incorporated into the initial design of each project, with the choice of evaluation technique based directly upon the specific project goals against which performance will be evaluated. We emphasize measurement of geomorphic characteristics, as these constitute the physical framework supporting riparian and aquatic ecosystems. Techniques for evaluating other components are briefly discussed, especially as they relate to geomorphic variables. Where possible, geomorphic, hydrologic, and ecological variables should be measured along the same transects. In general, postproject monitoring should continue for at least a decade, with surveys conducted after each flood above a predetermined threshold. Project design should be preceded by a historical study documenting former channel conditions to provide insights into the processes suggest earlier, potentially stable channel configurations as possible design models.

Wear and damage of ultrahigh molecular weight polyethylene (UHMWPE) tibial inserts used in total knee arthroplasty are accelerated by oxidation. Radiation crosslinking reduces wear but produces residual free radicals adversely affecting stability. One alternative to stabilize radiation-crosslinked UHMWPE is to infuse the material with vitamin E (vit E). We investigated the properties of 100-kGy e-beam-irradiated UHMWPE that was subsequently doped with vitamin E in comparison with conventional UHMWPE. Both polymers were sterilized with gamma irradiation in vacuum packaging. Vitamin E-doped UHMWPE showed lower wear before and after aging (2.4 ± 0.5 and 2.5 ± 0.8 mg/million cycle, respectively, vs 26.9 ± 3.5 and 40.8 ± 3.0 mg/million cycle for conventional UHMWPE). Conventional UHMWPE showed oxidation after accelerated aging, and its mechanical properties were adversely affected, whereas vit E-doped UHMWPE showed no oxidation or changes in its mechanical properties. Vitamin E stabilization of radiation-crosslinked UHMWPE resulted in low wear and high oxidation resistance; it is an alternative load-bearing material for total knee applications.

This paper describes the application of elastic inversion on real crosswell data, with the objective of discriminating sand and shale with high resolution at the reservoir level. For this work we used crosswell seismic profiles acquired at Belayim Land field, Sinai, Egypt. The results showed that elastic inversion of crosswell seismic data is able to discriminate between sand and shales with a resolution of 5m. Knowledge of Vs information at the reservoir level is important in order to obtain absolute results from the elastic inversion.

A series of 64 consecutive cases of children with neuroepthelial tumors of the cerebral hemispheres operated on from 1966 to 1983 is analyzed with regard to the long-term survival rate and the quality of life at late follow-up. At the time of the diagnosis the age of the patients ranged from 8 months to 15 years (mean age 7.6 years), and the relative incidence of these neoplasms was found to be about the same (37%) in the subgroups from 5 to 10 years and 11 to 15 years. It was only 9% in patients below 2 years of age. Tumor removal was radical in 84% and partial in 16% of the cases. The overall operative mortality was 14%, although it has been 4% since 1977. At histology, grade I and II lesions were found to account for 70% of the cases, and of the remaining 30% of the cases 8% were grade IV anaplastic lesions. The survival rate of the 55 survivors was calculated according to the actuarial life-table analysis. It was 62% at 5 years and 40% at 15 years. The survival rate at 5 years was 80% for low grade (I and II) tumors while it was 25% for high-grade malignancy (III–IV) tumors. The quality of life was assessed in all 29 patients with long-term survival (disease-free state lasting for at least 5 years) by adopting a specific protocol, which included repeated CT studies and neuropsychological evaluation. A more favorable prognosis was established for children operated on when over 6 years of age and with frontal and parietal neoplasms, while a poor functional prognosis was observed in children below 6 years of age and with temporal lobe tumors.

The Authors present the CT and MR findings in three patients with Krabbe disease: early infantile, late infantile and juvenile. Three children, 5 and 9 months old respectively with Krabbe disease, were studied with CT and MR. the children presented with spasticity and signs of peripheral neuropathy, blindness and no interaction with the environment. In all patient CT revealed nonenhancing discrete dense lesions, simmetrically distribuited in the posterior limb of the internal capsule and posterior thalami and focal hypodensities of the midcerebellar peduncles and dentate nuclei, with mild cerebral atrophy. In one patients CT demonstrated bilateral calcifications of paraventricular white matter. Mr, in all, showed a generalized increase in T2 values of the periventricular white matter. The thalami and adjacents regions had markedly shortened T1 and slightly shortenede T2. The cerebellum and the brainstem appeared mottled with scattered areas of increased T2. MR confirmed the cerebral atrophy. In conclusion CT and MR findings in Krabbe disease (early infantile and late infantile) are usually not specific. However when they are both performed at the onset of neurological symptoms they can alert clinicians to the possibility of Krabbe disease.

We report here the expression and properties of the intermediate-conductance Ca(2+)-activated K(+) (IK(Ca)) channel in the GL-15 human glioblastoma cell line. Macroscopic IK(Ca) currents on GL-15 cells displayed a mean amplitude of 7.2+/-0.8 pA/pF at 0 mV, at day 1 after plating. The current was inhibited by clotrimazole (CTL, IC(50)=257 nM), TRAM-34 (IC(50)=55 nM), and charybdotoxin (CTX, IC(50)=10.3 nM). RT-PCR analysis demonstrated the expression of mRNA encoding the IK(Ca) channel in GL-15 cells. Unitary currents recorded using the inside-out configuration had a conductance of 25 pS, a K(D) for Ca(2+) of 188 nM at -100 mV, and no voltage dependence. We tested whether the IKCa channel expression in GL-15 cells could be the result of an increased ERK activity. Inhibition of the ERK pathway with the MEK antagonist PD98059 (25 muM, for 5 days) virtually suppressed the IK(Ca) current in GL-15 cells. PD98059 treatment also increased the length of cellular processes and up-regulated the astrocytic differentiative marker GFAP. A significant reduction of the IKCa current amplitude was also observed with time in culture, with mean currents of 7.17+/-0.75 pA/pF at 1-2 days, and 3.11+/-1.35 pA/pF at 5-6 days after plating. This time-dependent downregulation of the IK(Ca) current was not accompanied by changes in the ERK activity, as assessed by immunoblot analysis. Semiquantitative RT-PCR analysis demonstrated a ~35% reduction of the IK(Ca) channel mRNA resulting from ERK inhibition and a approximately 50% reduction with time in culture.

A common strategy underlies three PCR-based methods for DNA fingerprinting developed in the early 1990s. Arbitrarily primed PCR (AP-PCR) (Welsh and McClelland 1990), random amplified polymorphic DNA (RAPD) assay (Williams et al. 1990) and DNA amplification fingerprinting (DAF) (Caetano-Anolles et al. 1991) are all based on the use of arbitrary primers to perform the PCR amplification of random genomic DNA fragments. Each primer (or combination of primers) generates a characteristic pattern of amplification products which is visualised by either radionuclide incorporation or ethidium bromide staining or silver staining. Polymorphisms between individuals (or strains) are detected as differences between the patterns of DNA fragments amplified from the different DNAs using a given primer(s).

Bell's palsy is caused by a nuclear and/or infranuclear lesion of the facial nerve, producing an ipsilateral deficit of the facial muscles. The etiology is unknown. Bell's palsy has a frequency of 20:100000 individuals/year, a familiarity of 1-2% of cases, and a recurrence rate of 9% of cases. We studied 33 children (mean age 9.1 years) admitted to our Division during the period 1991-1994 because of Bell's palsy. We propose our personal diagnostic and therapeutical trial: in every patient a full neurological and otoscopic examination, and an audioimpedenzometric test. Treatment is then commenced with prednisone (1 mg/kg/day p.o. for 5-10 days and gradual reduction in 5 days), vitamins B1, B6 and B12 p.o. for 30 days, and local treatment with artificial tears, and occlusive bandage at nighttime until the lagophthalmus is resolved. Electromyography-electroneurography, and brain CT-scan are carried out after 15 days and 21 days respectively of treatment, if neurological deficit is unchanged. 80 to 90% of patients are reported to recover spontaneously from Bell's palsy. With our approach we achieved a 100% recovery rate within an average of 3 weeks (range: 1 week to 5 months).

Twenty-eight children (mean age 8 years) with neurofibromatosis type 1 (NF1) and cerebral tumor were studied from 1975 to 1992 (mean follow-up 8.1 years) considering the biological behaviour of the tumor and the patient's quality of life, in order to identify retrospectively the best management. All, except one, tumors were benign gliomas, 76% of the optic nerve/chiasm (NCO), just 10% infratentorial. Sixteen children (57%) did not receive any treatment, 2 radiotherapy (RT) only and 4 symptomatic treatment only; in 6 patients the tumor resection was performed. 92% of the 25 survivors had sufficient autonomy in daily life at last follow-up. Considering the risk of cerebral tumors in patients with NF1, we conclude that cerebral magnetic resonance should be performed also in the asymptomatic ones. If neuroradiological findings are characteristic of benign glioma, histologic confirmation seems unnecessary. Surgical resection is recommended only in tumors confined to a single optic nerve, with severe or progressive symptoms. In chiasmatic tumors we suggest partial resection or symptomatic treatment only with close clinical and radiological observation. RT is only recommended if there is unequivocal evidence of tumor progression. Chemotherapy can delay the use of RT in very young children. Cerebral tumors different from NCO gliomas seem to have a similar natural history in patients with or without NF1 and therefore the management should be the same for both groups.

Eighty children who in the first 2 years of life had signs and symptoms relating to a cerebral neoplasm were studied over an 18-year period (1970–1987), the mean follow-up being 8.2 years. In each case age at onset, clinical presentation, tumor location and pathological diagnosis, extent of surgical resection, postoperative mortality, adjuvant therapy length of survival and quality of life were assessed. Supratentorial tumors (59%) were more common than infratentorial. The most frequent clinical presenting feature (70%) was increased intracranial pressure. Sixty-three patients (79%) were operated on and in all of these cases a histological diagnosis was obtained. Astrocytomas (41%) and medulloblastomas (20%) were the most common oncotypes. Surgical mortality was 17.4% and the 5-year survival rate was 54%. Quality of life was assessed for all long-term surviving patients using a specifically designed protocol. Normal physical and intellectual performances were found in 46% of cases, and all together 75% of the patients had sufficient autonomy in daily life. The prognosis is more closely related to tumor location and type of treatment than to histological diagnosis or age at onset.

An adaptive controller for multi-input multi-output (MIMO) systems is presented, which is able to modify repeatedly the control variables between successive output measurements. This feature makes the proposed approach particularly appealing for the control of composition products of distillation columns when expensive and slow chromatographs are used. The control algorithm is derived by minimizing the predicted error signal, as well as the control increments, over a future control horizon which is suitably selected. Applications to a simulated non-linear model of a binary distillation column demonstrate the effectiveness of the proposed method.

International audience; Cet article analyse la place du discours rapporté attribué à l'instance citoyenne et les commentaires dont il fait l'objet dans la couverture médiatique de la " révolution orange " par les quotidiens nationaux Le Monde, Le Figaro, Libération et L'Humanité. Partant de la perspective des sciences de l'information et de la communication et de celle de l'analyse du discours, l'étude de la reproduction de la parole citoyenne dans la presse permet de comprendre les spécificités du fonctionnement du journal en tant qu'espace public médiaté et d'introduire la question de la relation entre l'écrit et la parole.

Introduction and aims : Bilateral facial nerve palsy is a rare clinical entity, occuring in 0.3% to 2.0% of facial palsy cases. Although its pathogenesis remains unclear, this condition is often associated with systemic diseases and may represent a diagnostic challenge. Mycoplasma pneumoniae is a common cause of respiratory tract illness in children. Neurological complications are the most frequent extrapulmonary manifestation, but, so far, only a few case reports suggested an association between bilateral cranial nerve palsy and M. pneumoniae infection. We describe a patient who developed bilateral facial nerve palsy with a serologically-proved mycoplasma infection. Case report (methods and results): a previously healthy 10-year-old boy was admitted to our department because of sudden onset of peripheral left facial nerve palsy evolved in facial diplegia during the first 24 hours of hospitalization. He had a 15-day history of fever, coughing and vomiting accompanied by asthenia and headache. His physical examination was remarkable for bilateral facial nerve palsy, with no signs of meningism and papilledema, and the remainder of physical examination was normal. He had a positive throat swab culture for S. Pyogenes; chest X-ray, EEG and cerebrospinal fluid examination revealed no pathological findings. PCR for neurotropic virus as well as for Borrelia burgdorferi were negative, but serum M. pneumonie antibodies were positive, indicating an acute infection (IgM and IgG – titer 1:320). Brain MRI revealed a bilateral and symmetric enhancement of the VII cranial nerves. He was treated with intravenous ceftriaxone for 8 days and oral clarithromycin for 14 days. He rapidly improved, the bilateral nerve palsy resolved completely and spontaneously within 20 days, and no recurrences were noted during his follow-up visits. Conclusions: various infectious agents have been linked to bilateral facial palsy, such as EBV, HIV, Borrelia burgdorferi and Mycoplasma pneumoniae. The spectrum of CNS complications following mycoplasmal infection is wide, but whereas to date the association between encephalitis and mycoplasma infection is accepted, bilateral facial palsy due to M. pneumoniae has been reported in only five cases. Our patient developed a bilateral facial nerve palsy after complained of mild respiratory symptoms; no pulmonary infection was documented but a seroconversion of M. pneumoniae could be detected. The absence of respiratory symptoms in neurologic complications following mycoplasma infection is not a rare event and the number of mycoplasma infections might be higher than recognized so far. Patients presenting with a bilateral facial palsy of unknown origin should be tested for antibodies against M. pneumoniae, regardless of the presence or absence of respiratory symptoms.