Retinal changes in multiple sclerosis: An optical coherence tomography and angiography study.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system with neuroaxonal damage. It is the principal driver of non-traumatic disability in young adults. Visual symptoms are common and optic neuritis (ON) may be the revealing feature in up to 30% of cases. Structural optical coherence tomography (OCT) represents a biomarker of central nervous system neurodegeneration in MS. OCT-angiography (OCT-A) is a noninvasive tool allowing the study of retinal vasculature and the detection of microvascular damage in neuro-retinal diseases. In this study, we aimed to assess structural and microvascular retinal changes in patients with MS with and without ON and to correlate the findings with visual function and MS disability. METHODS: We conducted a cross-sectional study including patients diagnosed with MS according to the 2017 McDonald criteria. All patients underwent complete neurological examination with evaluation of the Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Severity Score (MSSS) and an ophthalmological examination including OCT and OCT-A. Patients were compared with age- and sex-matched healthy subjects. The primary endpoints were assessment of retinal nerve fiber layer (RNFL) thickness, ganglion cell layer (GCL+), and ganglion cell complex (GCL++) thicknesses on OCT. Vascular densities in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) were assessed on OCT-A, as well as central avascular zone (CAZ) parameters, lacunarity and fractal dimension. RESULTS: A total of 160 MS eyes with and without a previous history of ON and 64 age- and gender-matched healthy eyes were analyzed. Among 160 eyes with MS, 69 had a history of ON. We observed a decrease in RNFL and GCL++ thickness in all 12 quadrants in MS patients when compared to healthy controls. Multivariate analysis by linear regression noted a significant correlation for temporal GCL++ and inferonasal RNFL thickness that were decreased in the MS group. A greater decrease in retinal layers thickness was identified in MS patients with a history of ON. On OCT-A, vascular density in (SCP) was significantly reduced in the MS group (P<0.002). A significant correlation between RNFL thickness and retinal vascular density was found but only in less than half of the hourly quadrants. A significant correlation was noted between visual acuity and CC density (P<0.0001). We also noted an inverse correlation between EDSS scores and CC density (P=0.02 and r=-0.275) and between MSSS and RNFL/GCL++ thicknesses. CONCLUSIONS: RNFL and GCL++ layers were thinner in MS patients with a history of ON and were reversely correlated with disease severity. Moreover, retinal vascular changes were observed in MS even in eyes without ON, and CC was reversely correlated with visual function and current disability. Thus, structural OCT coupled with OCT-A could represent a noninvasive and dynamic biomarker of MS severity and progression.

Arabic adaptation of the Edinburgh cognitive and behavioural Amyotrophic lateral sclerosis screen (ECAS-AR).

Current screening batteries for assessing neuropsychological function are not specific for Amyotrophic Lateral Sclerosis (ALS) and are considered as limited tools due to the physical disabilities associated with ALS. The Edinburgh Cognitive and Behavioural ALS screen (ECAS) was developed to detect the specific cognitive and behavioral changes that may occur among ALS patients. This study presents the ECAS developed for Arabic-speaking ALS patients (ECAS-AR) for use by healthcare professionals. ECAS was translated and modified to refined variety of Arabic language. Eighty-five ALS patients were included. Normative data were collected from 200 healthy controls (among them 97 were matched). Subjects were administered the ECAS-AR and two conventional cognitive screening batteries, Frontal Assessment Battery (FAB) and Mini-Mental State Examination (MMSE). ECAS-AR discriminated well between healthy controls and ALS patients. Significant differences were noted in language, executive functions, memory, and visuospatial domains between the two groups. The most prevalent deficit occurred in language and executive functions in ALS-specific functions. Whereas memory was more readily impaired in the lower and middle education groups concerning ALS non-specific functions. Verbal fluency tended to be preserved. Positive correlations were found between ECAS-AR and the standard cognitive tests supporting its full validity. The ECAS-AR version proposed will provide rapid, efficient and sensitive tools for healthcare professional to determine the cognitive-behavioural profile in Arabic-speaking ALS patients.

Original implementation of low-temperature SPS for bioactive glass used as a bone biomaterial.

Alkali borated bioactive glasses powders with compositions based on the SiO2-Na2O-CaO-P2O5-x B2O3 system (0 < x < 20 wt%); have been consolidated at low temperature using Spark Plasma Sintering (SPS). Through SPS technique under 50 MPa, it was possible to achieve fully dense and completely amorphous borated glasses at temperatures as low as 420 °C. By increasing the sintering temperature up to 430 °C, the dense samples crystallized which is mostly achieved at higher temperatures. This study reveals that the mechanical properties of these new borated biomaterials are suitable to be used as a promising candidate for repairing defects in non-load-bearing bones as well as for coating on the metallic surface implants to improve the bioactivity process bone/implant. The pressure had a weak effect on the crystallization and densification of the glass compared to the temperature during the powder consolidation by SPS. Moreover, by increasing the boron content, the compressive strength and the elastic modulus of the elaborated glasses decreased for being close to those of the natural.

Tunisian version of the brief international cognitive assessment for multiple sclerosis: Validation and normative values.

BACKGROUND: The Brief International cognitive assessment for Multiple sclerosis (BICAMS) is a specific batterie used to identify cognitive impairment in Multiple Sclerosis (MS) in a reliable and easy way. To date, for the Arabic-speaking Tunisian MS patients, there is no consensus for the use of specific cognitive batteries in MS. OBJECTIVE: The aim of our work was to develop and validate the Tunisian version of the BICAMS (T-BICAMS) and to determine our own normative values. MATERIAL AND METHODS: Patients diagnosed with MS and followed up in the department of Neurology of Razi Hospital were recruited and matched to healthy controls according to age, sex and educational level. T-BICAMS validity was established by comparing MS and healthy controls for symbol digit modalities test (SDMT), brief visual memory test (BVMT-R) and Tunisian verbal learning tests (TVLT) which was used instead of the California verbal learning test (CVLT-II). RESULTS: The 104 MS patients and 104 healthy controls were comparable for age, sex and educational level. The MS group exhibited lower performances in all T-BICAMS domains compared to healthy controls: SDMT (x003Dp<10-3), BVMT-R (p = 0.002) and TVLT (p x003D<10-3). T-BICAMS Cronbach alpha value was 0.741. Normative values were identified for patients with MS: SDMT [39-40], BVMT-R [26-27] and TVLT [43-44]. Cognitive impairment was identified among 76 patients (73.1%). Males, lower educational levels and progressive MS were associated with a more severe cognitive impairment. CONCLUSIONS: The current study has established the BICAMS as a valid and reliable tool for the identification of cognitive impairment in the Tunisian MS population.

Monitoring genotoxicity in freshwater microcrustaceans: A new application of the micronucleus assay.

We have applied the micronucleus (MN) assay to the measurement of genotoxicity in microcrustaceans. Daphnids (Daphnia magna) and Copepods (Acanthocyclops robustus) were collected in situ and acclimated in the lab for 24h. The MN assay was successful with the Daphnids but not with the Copepods. Adult Daphnids were exposed to sublethal concentrations of metals (Cu, Zn, Cd) or insecticide (deltamethrin) for 2 and 7d. Dose-dependent induction of MN was observed after 2 d exposure, with 2-fold induction at the highest doses for each chemical tested. The advantages and ecological relevance of using Daphnids in genotoxicity assessment are highlighted. The Daphnid assay may be a reliable test for aquatic genotoxicity hazard/risk assessment and a useful alternative to studies of amphibians.

Effect of an external electric field on the smectic-Ctilted* phases.

We are interested in the chiral tilted smectic subphases, smectic-C(tilted)(*), including commensurate structures as well as the incommensurate smectic-C(α)(*) one. The continuum theory defines two scalar order parameters I and J, which can be coupled with an external electric field through a linear term I × E and a dielectric term J × E(2). We have calculated the changes due to these terms in the phase diagrams in the (α,η) plane, where α comes from the spontaneous twist and η measures the strength of the biaxial order. The coupling with an external electric field induces the expansion of the areas with spontaneous polarization and the appearance of an electroazimuthal effect.

Scheduling IT staff at a bank: a mathematical programming approach.

We address a real-world optimization problem: the scheduling of a Bank Information Technologies (IT) staff. This problem can be defined as the process of constructing optimized work schedules for staff. In a general sense, it requires the allocation of suitably qualified staff to specific shifts to meet the demands for services of an organization while observing workplace regulations and attempting to satisfy individual work preferences. A monthly shift schedule is prepared to determine the shift duties of each staff considering shift coverage requirements, seniority-based workload rules, and staff work preferences. Due to the large number of conflicting constraints, a multiobjective programming model has been proposed to automate the schedule generation process. The suggested mathematical model has been implemented using Lingo software. The results indicate that high quality solutions can be obtained within a few seconds compared to the manually prepared schedules.

[An uncommon cause of dyspnea in children. Plexiform neurofibroma of the larynx]. / Une cause rare de dyspnée: neurofibrome plexiforme du larynx.

Plexiform neurofibroma is a rare benign tumor developed from cells of the sheath of Schwann peripheral nervous system often associated with neurofibromatosis type 1 or Von Recklinghausen disease. Laryngeal involvement in neurofibromatosis is rare and usually presents with obstructive respiratory symptoms. Imaging including CT and MRI provides the diagnosis as well as the staging of this lesion, whose treatment is primarily surgical. We report the case of a plexiform neurofibroma of the larynx found in a 4-year-old child revealing a mass completely obstructing the laryngeal vestibule.

Real-time PCR using SYBR Green for the detection of Shigella spp. in food and stool samples.

Shigella spp are exquisitely fastidious Gram negative organisms that frequently get missed in the detection by traditional culture methods. For this reason, this work has adapted a classical PCR for detection of Shigella in food and stool specimens to real-time PCR using the SYBR Green format. This method follows a melting curve analysis to be more rapid and provide both qualitative and quantitative data about the targeted pathogen. A total of 117 stool samples with diarrhea and 102 food samples were analyzed in Public Health Regional Laboratory of Nabeul by traditional culture methods and real-time PCR. To validate the real-time PCR assay, an experiment was conducted with both spiked and naturally contaminated stool samples. All Shigella strains tested were ipaH positive and all non-Shigella strains yielded no amplification products. The melting temperature (T(m) = 81.5 ± 0.5 °C) was consistently specific for the amplicon. Correlation coefficients of standard curves constructed using the quantification cycle (C(q)) versus copy numbers of Shigella showed good linearity (R² = 0.995; slope = 2.952) and the minimum level of detection was 1.5 × 10³ CFU/g feces. All food samples analyzed were negative for Shigella by standard culture methods, whereas ipaH was detected in 8.8% culture negative food products. Moreover, the ipaH specific PCR system increased the detection rate over that by culture alone from 1.7% to 11.1% among patients with diarrhea. The data presented here shows that the SYBR Green I was suitable for use in the real-time PCR assay, which provided a specific, sensitive and efficient method for the detection and quantification of Shigella spp in food and stool samples.

Detection and characterization of Shigella species isolated from food and human stool samples in Nabeul, Tunisia, by molecular methods and culture techniques.

AIMS: This study was designed to isolate Shigella spp. strains from food and stool samples by a combination of PCR and culture methods and characterize their serotypes, antibiotic resistance profiles, virulence genes and pulsed-field gel electrophoresis (PFGE) patterns to investigate possible clonal relationships amongst strains circulating. METHODS AND RESULTS: Six Shigella spp. strains were isolated from 280 food samples against 16 Shigella isolates from 236 stool samples of symptomatic patients and asymptomatic food handlers during the period from January 2007 to December 2009 in Public Health Regional Laboratory of Nabeul. The detection of ipaH, ipaBCD, ial, ShET-1 and ShET-2 was performed by a PCR technique with specific primers. CONCLUSIONS: The use of PCR technique improved the rate of detecting Shigella in stool samples from 6·7 to 14% and in food samples from 2·1 to 8·6%. Percentage of Shigella isolates and ipaH-specific PCR demonstrated a marked pattern of seasonality, increasing in summer and fall seasons for human and food isolates. Amongst the environmental strains, 50% of isolates were invasive. However, for the 16 clinical strains isolated, nine were found to be positive for both ial and ipaBCD gene and 11 were found to produce ShET-1 and/or ShET-2. XbaI PFGE analysis revealed the presence of a predominant clone amongst Shigella sonnei strains recovered from different sources circulating in Nabeul, Tunisia, throughout the years 2007-2009. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the existence of Shigella in food samples and dispersion of different virulence genes amongst these isolates, which appear to constitute an environmental source of epidemic spread. The clonal relationships amongst strains isolated from food elements and human stools indicate the incrimination of different kinds of foods as vehicle of transmission of Shigella, which are usually escaped from detection by traditional culture methods.

Laparoscopic incisional hernia repair after solid-organ transplantation.

BACKGROUND: Incisional hernias are a frequent problem after liver transplantation. Mesh repair techniques including laparoscopic repair have been employed in order to address this problem. We have introduced intraperitoneal onlay mesh repair (IPOM) in 2008 because of advantages that had been reported in the literature. To perform a structured comparison of methods and outcomes, we compared patients who have been treated with IPOM and those who have been treated conventionally. METHODS: We included 29 consecutive patients (15 IPOM, 14 conventional hernia repair [CHR] who have been analyzed and have been examined clinically and sonographically during their follow-up. RESULTS: Recurrence rate was 6% (IPOM) and 50% (CHR), complication rate was 33% (IPOM) and 21% (CHR), mean hospital stay was 7.2 (IPOM) and 9.7 (CHR) days. None of the 29 patients had an impaired wound healing or infectious complications. Of the 29 patients, 10 received sirolimus for immunosuppression, which was switched preoperatively to a calcineurin inhibitor. CONCLUSION: IPOM results in a shorter hospital stay. The complication rate with IPOM was higher compared with CHR, recurrence rate was considerably lower. The role of perioperative sirolimus switch needs to be interpreted with caution, but should be further investigated because of potential advantages with respect to fewer wound healing complications.

Concentration regimes and denaturation effects on the conformational changes of α-chymotrypsin by viscosity and dynamic light scattering measurements.

This work focused on the conformational changes of α-chymotrypsin from bovine pancreas for various concentrations as well as the effects of chemical denaturation and organic solvents using both of viscosity and dynamic light scattering techniques. A wide range of concentrations varying between 0.1 and 30 mg/ml is tested to determine the critical concentration c** that separates the extremely dilute regime to the dilute regime and the overlapping concentration c* that separates the dilute regime to the semi-dilute regime. The knowledge of α-chymotrypsin folding process is followed for a range of chemical denaturant concentrations varying from 1 to 6 M. We showed that the α-chymotrypsin folds through a cooperative two-state transition without detectable kinetic intermediates and the formation of 50% unfolded happens for 5.5 M of urea or guanidinium chloride (GdmCl) concentrations. The action modes of the acetonitrile on the conformational changes of α-chymotrypsin are also achieved for concentrations varying between 10 and 50%.

Extension of the Hamaneh-Taylor model using the macroscopic polarization for the description of chiral smectic liquid crystals.

Chiral smectic liquid crystals exhibit a series of phases, including ferroelectric, antiferroelectric, and ferrielectric commensurate structures as well as an incommensurate Sm-Calpha* phase. We carried out an extension of the phenomenological model recently presented by Hamaneh and Taylor based on the distorted-clock model. The salient feature of this model is that it links the appearance of phases to a spontaneous microscopic twist: i.e., an increment alpha of the azimuthal angle from layer to layer. The balance between this twist and an orientational order parameter J gives the effective phase. We introduce a second orientational order parameter I , which physical meaning comes from the macroscopic polarization; the effect of an applied electric is also studied. We derive phase diagrams and correlate them to our experimental results under field showing the sequence of phases versus temperature and electric field in some compounds.

Foetus-in-fetu: an unusual cause of abdominal mass in the newborn.

Foetus-in-fetu (FIF) is a rare congenital condition in which a vertebrate foetus is incorporated within its twin. The authors report the case of a newborn girl with prenatal ultrasonographic diagnosis of an intra-abdominal mass. Abdominal ultrasonography and computed tomography of the abdomen showed a heterogeneous cystic mass containing multiple calcifications. The patient had a laparotomy at 18 days of age with excision of a well-encapsulated 6 x 5 cm retroperitoneal mass, containing many organs. Anatomicopathologic examination showed a relatively well-differentiated FIF attached to an amniotic sac by a rudimentary umbilical cord. Encephalon, coroidal plexus, vertebral bodies, rudimentary limbs, thyroid gland and teeth were identified. The postoperative period was uneventful.

Field-temperature phase diagrams in chiral tilted smectics, evidencing ferroelectric and ferrielectric phases.

Usual ferroelectric compounds undergo a paraelectric-to-ferroelectric phase transition when the susceptibility of the electric polarization density changes its sign. The temperature is the only thermodynamic field that governs the phase transition. Chiral tilted smectics may also present an improper ferroelectricity when there is a tilt angle between the average long axis direction and the layer normal. The tilt angle is the order parameter of the phase transition which is governed by the temperature. Although the electric susceptibility remains positive, a polarization proportional to the tilt appears due to their linear coupling allowed by the chiral symmetry. Further complications come in when the chirality increases, as new phases are encountered with the same tilt inside the layers but a distribution of the azimuthal direction which is periodic with a unit cell of two (SmC(A)*, three (SmC(Fi1)*, four (SmC(Fi2)* or more (SmC(alpha)* layers. In most of these phases, the layer normal is a symmetry axis so there is no macroscopic polarization except for the SmC(Fi1)* in which the average long axis is tilted so the phase is ferrielectric. By studying a particular compound with only a SmC(Fi2)* and a SmC(alpha)* phase, we show that we recover the uniformly tilted ferroelectric SmC* when applying an electric field. We are thus led to build field-temperature phase diagrams for this class of compounds by combining different experimental techniques described here.

Kinetics of phase separation in ramified polymer blends of arbitrary topology.

We present here a theoretical study of kinetics of phase separation within a mixture made of two chemically incompatible ramified polymers. For simplicity, we assume that they have the same topology. We are interested in the variation of the relaxation rate, tau(q), versus the wave number q, in the vicinity of the spinodal temperature. The kinetics is governed by local (Rouse) and reptation motions (faster and slower modes). For qRG >> 1 (RG being the gyration radius), kinetics is entirely controlled by local motions where each chain moves inside its own tube, and we show that the corresponding characteristic frequency, tau(q)(-1), scales as tau(q)(-1) approximately kappaGq6, where kappaG is a known topological factor. For qR(G) << 1, however, kinetics is rather dominated by long-wavelength (reptation) motions where unlike ramified polymers creep inside a long tube. For this case, we find that tau(q)(-1) approximately delta (0) q2 (chi(c) - chi), where delta (0) is another known topological factor that represents the total mobility of free monomers belonging to connected chains and reticulation points, and chi(c) accounts for the critical value of the segregation parameter. Finally, the derived relaxation rate must be compared to that relative to a linear polymer mixture.

[Risk factors of leishmanin-skin test positivity in transmission of Leishmania infantum in the center of Tunisia]. / Les déterminants de la positivité au test cutané à la leishmanine dans l'aire de transmission de Leishmania infantum dans le centre tunisien.

This work aims to estimate prevalence and evaluate risk factors of leishmanin-skin test positivity. A cross-sectional leishmanin skin test study was carried out on a sample of 3190 healthy volunteers living in the gouvernorates of Kairouan and Kasserine. Age standardized prevalence of leishmanin-skin test positivity was 45.9% (CI95% = [43.9-47.9]) confirming the hyper endemicity of this region. The rate of leishmanin-skin test positivity ranged from 75.9% (CI95% = [71.9-79.5]) in Zaghdoud (Kairouan) to 6.5% (CI95% = [3.7-11.01) in Abdeladhim (Kasserine). There is no significant difference between men and women suggesting a similar exposure to infection. In the districts of Zaghdoud, Sidi Amor, El Hajeb and chbika, age specific rates showed a rapid increasing positive prevalence with age reaching a proportion exceeding 80% after the age of 15 years. However, the age specific prevalence from other delegations showed a progressive increasing trend with age, with a low rate for younger children and a plateau of 75% after 45 years. Multivariate analysis of leishmanin-skin test positivity risk factors showed that only district and age are determinants of this infection.