Can external work during walking in scoliosis patients be estimated from spatiotemporal parameters?

BACKGROUND

Patients with scoliosis present gait impairments compared to healthy subjects. Clinically, spine deformity is evaluated with Cobb angle, a standard measurement to determine and track the progression of scoliosis. Scoliosis is a biomechanical trouble, dependant of external forces and muscular activity. External work is currently analyzed in patients with scoliosis because this work sums up consequences and evolutions of spine deformity. Habitually, biomechanics approach is used to compute this work. For asymptomatic subjects, a regression model let to compute external work. So, considering the area of research to facilitate the follow-up at lower cost, this regression function could be applied to patients with scoliosis but need to be validated.

RESEARCH QUESTION

can external work during walking in scoliosis patients be estimated from spatiotemporal parameters with a regression model?

METHOD

This retrospective study included twenty untreated patients with idiopathic scoliosis and sixteen asymptomatic participants. We used a regression model defined in case of asymptomatic subjects in literature and proposed a new specific model in case of patients with scoliosis.

FINDINGS

The external work in patients with scoliosis calculated with the Wirta's regression eq. (0.23 ± 0.04 J.kg-1.m-1) was underestimated compared to the external work calculated using a biomechanical method (0.33 ± 0.06 J.kg-1.m-1). A new regression model including Cobb angle and spatio-temporal parameter presents a high coefficient of determination.

INTERPRETATION

In opposition to biomechanical method, our new model let to compute external work without expensive gait laboratory. This specific model is more reliable than the model developed from asymptomatic subjects.

Toe-walking and its impact on first and second rocker in gait patterns with different degrees of artificially emulated soleus and gastrocnemius contracture

BACKGROUND

Toe-walking is one of the most common gait deviations (due to soleus and/or gastrocnemius muscle contractures), compromising the first (heel rocker) and second (ankle rocker) of the foot during walking. The aim of this study is to evaluate the effect of emulated artificially gastrocnemius and soleus contractures on the first and second rocker during walking.

METHOD

An exoskeleton was built to emulate contractures of the bilateral gastrocnemius and soleus muscles. Ten healthy participants were recruited to walk under the following conditions: without emulated contractures or with bilateral emulated contractures at 0°,10°, 20° and 30° of plantarflexion of the soleus or gastrocnemius in order to create an artificial restriction of dorsiflexion ankle movement. A linear regression from the ankle plantar-dorsiflexion angle pattern was performed on 0-5 % of the gait cycle (first rocker) and on 12-31 % of the gait cycle (second rocker) to compute the slope of the curve. The proportion of participants with the presence of the first and second rocker was then computed. A Statistical Parametric Mapping (SPM) analysis assessed the kinematic variations among different degrees of emulated contractures.

FINDINGS

The first and second rockers are completely absent from 10° of plantarflexion emulated contracture. The data indicate there was a non-linear shift of the gait pattern of the ankle kinematics and an important shift toward plantarflexion values with the loss of the rockers.

INTERPRETATION

This study suggests that toe-walking in the experimental simulation situation is not necessarily due to a high emulated contracture level and can occur with a small emulated contracture by an adaptation choice. This study may improve interpretation of clinical gait analysis and shows that the link between the level of gastrocnemius/soleus emulated contracture and progression of toe-walking (increased plantarflexion during gait) is not linear.

Synthesis of Neuraminidase-Resistant Sialyllactose Mimetics from N-Acyl Mannosamines using Metabolically Engineered Escherichia coli

Herein, we describe the efficient gram-scale synthesis of α2,3- and α2,6-sialyllactose oligosaccharides as well as mimetics from N-acyl mannosamines and lactose in metabolically engineered bacterial cells grown at high cell density. We designed new Escherichia coli strains co-expressing sialic acid synthase and N-acylneuraminate cytidylyltransferase from Campylobacter jejuni together with the α2,3-sialyltransferase from Neisseria meningitidis or the α2,6-sialyltransferase from Photobacterium sp. JT-ISH-224. Using their mannose transporter, these new strains actively internalized N-acetylmannosamine (ManNAc) and its N-propanoyl (N-Prop), N-butanoyl (N-But) and N-phenylacetyl (N-PhAc) analogs and converted them into the corresponding sialylated oligosaccharides, with overall yields between 10 % and 39 % (200-700 mg.L-1 of culture). The three α2,6-sialyllactose analogs showed similar binding affinity for Sambucus nigra SNA-I lectin as for the natural oligosaccharide. They also proved to be stable competitive inhibitors of Vibrio cholerae neuraminidase. These N-acyl sialosides therefore hold promise for the development of anti-adhesion therapy against influenza viral infections.

Hijacking the Peptidoglycan Recycling Pathway of Escherichia coli to Produce Muropeptides

Soluble fragments of peptidoglycan called muropeptides are released from the cell wall of bacteria as part of their metabolism or as a result of biological stresses. These compounds trigger immune responses in mammals and plants. In bacteria, they play a major role in the induction of antibiotic resistance. The development of efficient methods to produce muropeptides is, therefore, desirable both to address their mechanism of action and to design new antibacterial and immunostimulant agents. Herein, we engineered the peptidoglycan recycling pathway of Escherichia coli to produce N-acetyl-β-D-glucosaminyl-(1→4)-1,6-anhydro-N-acetyl-β-D-muramic acid (GlcNAc-anhMurNAc), a common precursor of Gram-negative and Gram-positive muropeptides. Inactivation of the hexosaminidase nagZ gene allowed the efficient production of this key disaccharide, providing access to Gram-positive muropeptides through subsequent chemical peptide conjugation. E. coli strains deficient in both NagZ hexosaminidase and amidase activities further enabled the in vivo production of Gram-negative muropeptides containing meso-diaminopimelic acid, a rarely available amino acid.

Size-Controlled Synthesis of β(1→4)-GlcNAc Oligosaccharides Using an Endo-Glycosynthase

Chitin and peptidoglycan fragments are well recognized as pathogen associated molecular patterns (PAMPs). Long-chain oligosaccharides of β(1→4)-linked N-acetyl-D-glucosamine (GlcNAc) units indeed activate plants and mammals innate immune system. However, the mechanisms underlying PAMPs perception by lysine motif (LysM) domain receptors remain largely unknown because of insufficient availability of high-affinity molecular probes. Here, we report a two-enzyme cascade to synthesize long-chain β(1→4)-linked GlcNAc oligomers. Expression of the D52S mutant of hen egg-white lysozyme (HEWL) in Pichia pastoris at 52 mg L^-1 provided a new glycosynthase catalyzing efficient polymerization of α-chitintriosyl fluoride. Selective N-deacetylation at the non-reducing unit of the glycosyl fluoride donor by Sinorhizobium meliloti NodB chitin-N-deacetylase abolished its ability to be polymerized by the glycosynthase but not to be transferred onto an acceptor. Using NodB and D52S HEWL in a one-pot cascade reaction allowed the synthesis on a milligram scale of chitin hexa-, hepta- and octasaccharides with yields up to 65 % and a perfect control over their size.

Unprecedented Affinity Labeling of Carbohydrate-Binding Proteins with s-Triazinyl Glycosides

Carbohydrate-protein interactions trigger a wide range of biological signaling pathways, the mainstays of physiological and pathological processes. However, there are an incredible number of carbohydrate-binding proteins (CBPs) that remain to be identified and characterized. This study reports for the first time the covalent labeling of CBPs by triazinyl glycosides, a new and promising class of affinity-based glycoprobes. Mono- and bis-clickable triazinyl glycosides were efficiently synthesized from unprotected oligosaccharides (chitinpentaose and 2'-fucosyl-lactose) in a single step. These molecules allow the specific covalent labeling of chitin-oligosaccharide-binding proteins (wheat germ agglutinin WGA and Bc ChiA1 D202A, an inactivated chitinase) and fucosyl-binding lectin (UEA-I), respectively.

Molecular imaging of neuroinflammation in patients after mild traumatic brain injury: a longitudinal 123 I-CLINDE single photon emission computed tomography study

BACKGROUND AND PURPOSE

Neuroinflammation has been proposed as part of the pathogenesis of post-concussion symptoms (PCS), but the inflammatory response of the human brain to mild traumatic brain injury (mTBI) remains unknown. We hypothesized that a neuroinflammatory response is present in mTBI at 1-2 weeks post-injury and persists in patients with PCS.

METHODS

We scanned 14 patients with mTBI without signs of structural damage at 1-2 weeks and 3-4 months post-injury and 22 healthy controls once using the single photon emission computed tomography tracer ¹²³ I-CLINDE, which visualizes translocator protein (TSPO), a protein upregulated in active immune cells. PCS was defined as three or more persisting symptoms from the Rivermead Post Concussion Symptoms Questionnaire at 3 months post-injury.

RESULTS

Across brain regions, patients had significantly higher ¹²³ I-CLINDE binding to TSPO than healthy controls, both at 1-2 weeks after the injury in all patients (P = 0.011) and at 3-4 months in the seven patients with PCS (P = 0.006) and in the six patients with good recovery (P = 0.018). When the nine brain regions were tested separately and results were corrected for multiple comparisons, no individual region differed significantly, but all estimated parameters indicated increased ¹²³ I-CLINDE binding to TSPO, ranging from 2% to 19% in all patients at 1-2 weeks, 13% to 27% in patients with PCS at 3-4 months and -9% to 17% in patients with good recovery at 3-4 months.

CONCLUSIONS

Neuroinflammation was present in mTBI at 1-2 weeks post-injury and persisted at 3-4 months post-injury with a tendency to be most pronounced in patients with PCS.

Brain comorbidities in normal pressure hydrocephalus

BACKGROUND AND PURPOSE

This cross-sectional study aims to compare gait changes after the cerebrospinal fluid (CSF) tap test between normal pressure hydrocephalus patients with and without brain comorbidities (NPH+ and NPH- respectively) and then to identify significant contributors to a poor CSF tap test amongst individuals with NPH+.

METHODS

Gait changes (during the single task and the dual task of backward counting) were quantified before and 24 h after the CSF tap test with an optoelectronic system in 52 NPH patients (77.4 ± 6.0 years; 34.6% women). Changes after the CSF tap test in stride time variability (STV, %) were our main outcome. CSF Alzheimer's disease biomarkers, cerebrovascular white matter changes assessed with brain imaging and neurodegenerative diseases with parkinsonian syndrome represented the three individual brain comorbidities.

RESULTS

Brain comorbidities were frequently identified, NPH+ patients representing 40 patients of our sample (76.9%). NPH- patients improved their STV better in the single task (delta of STV = -58.6% ± 54.3% vs. -14.1% ± 62.0%; P = 0.031) and in the dual task (delta of STV =-32.2% ± 33.7% vs. 6.3% ± 58.4%; P = 0.028) after the CSF tap test than NPH+ patients. Amongst NPH+ individuals, only comorbid Alzheimer's disease was associated with STV increase (i.e. deterioration of gait) in the dual task [β 38.4; 95% confidence interval (5.64; 71.24); P = 0.023] after the CSF tap test, whilst it was borderline in the single task [β 35.0; 95% confidence interval (-1.97; 71.90); P = 0.063].

CONCLUSIONS

Brain comorbidities affect gait improvement after the CSF tap test in NPH patients; this influence is driven by Alzheimer's disease-related pathology.

Influence of different degrees of bilateral emulated contractures at the triceps surae on gait kinematics: The difference between gastrocnemius and soleus

INTRODUCTION

Ankle plantarflexion contracture results from a permanent shortening of the muscle-tendon complex. It often leads to gait alterations. The objective of this study was to compare the kinematic adaptations of different degrees of contractures and between isolated bilateral gastrocnemius and soleus emulated contractures using an exoskeleton.

METHODS

Eight combinations of contractures were emulated bilaterally on 10 asymptomatic participants using an exoskeleton that was able to emulate different degrees of contracture of gastrocnemius (biarticular muscle) and soleus (monoarticular muscle), corresponding at 0°, 10°, 20°, and 30° ankle plantarflexion contracture (knee-flexed and knee-extended). Range of motion was limited by ropes attached for soleus on heel and below the knee and for gastrocnemius on heel and above the knee. A gait analysis session was performed to evaluate the effect of these different emulated contractures on the Gait Profile Score, walking speed and gait kinematics.

RESULTS

Gastrocnemius and soleus contractures influence gait kinematics, with an increase of the Gait Profile Score. Significant differences were found in the kinematics of the ankles, knees and hips. Contractures of soleus cause a more important decrease in the range of motion at the ankle than the same degree of gastrocnemius contractures. Gastrocnemius contractures cause greater knee flexion (during the stance phase) and hip flexion (during all the gait cycle) than the same level of soleus contractures.

CONCLUSION

These results can support the interpretation of the Clinical Gait Analysis data by providing a better understanding of the effect of isolate contracture of soleus and gastrocnemius on gait kinematics.

A fatal endocarditis case due to an emerging bacterium: Moraxella nonliquefaciens

Moraxella nonliquefaciens is a Gram-negative coccobacillus considered as a commensal organism from the upper respiratory tract, with low pathogenic potential. The phenotypical conventional identification is difficult and the matrix-assisted laser desorption/ionization time-of-flight technology has increased the resolution of identification of this bacterium. We report a fatal case of endocarditis due to M. nonliquefaciens whose identification was confirmed by 16S rRNA, and we review the literature on this pathogen in endocarditis.

Feasibility and reliability of using an exoskeleton to emulate muscle contractures during walking

Contracture is a permanent shortening of the muscle-tendon-ligament complex that limits joint mobility. Contracture is involved in many diseases (cerebral palsy, stroke, etc.) and can impair walking and other activities of daily living. The purpose of this study was to quantify the reliability of an exoskeleton designed to emulate lower limb muscle contractures unilaterally and bilaterally during walking. An exoskeleton was built according to the following design criteria: adjustable to different morphologies; respect of the principal lines of muscular actions; placement of reflective markers on anatomical landmarks; and the ability to replicate the contractures of eight muscles of the lower limb unilaterally and bilaterally (psoas, rectus femoris, hamstring, hip adductors, gastrocnemius, soleus, tibialis posterior, and peroneus). Sixteen combinations of contractures were emulated on the unilateral and bilateral muscles of nine healthy participants. Two sessions of gait analysis were performed at weekly intervals to assess the reliability of the emulated contractures. Discrete variables were extracted from the kinematics to analyse the reliability. The exoskeleton did not affect normal walking when contractures were not emulated. Kinematic reliability varied from poor to excellent depending on the targeted muscle. Reliability was good for the bilateral and unilateral gastrocnemius, soleus, and tibialis posterior as well as the bilateral hamstring and unilateral hip adductors. The exoskeleton can be used to replicate contracture on healthy participants. The exoskeleton will allow us to differentiate primary and compensatory effects of muscle contractures on gait kinematics.

Neither Neoplasia Nor Tuberculosis, but Francisella

Tularaemia is an emerging anthropozoonosis transmitted by contact with infected animals and through arthropod bites, inhalation, or ingestion. We describe a pulmonary nodule suggesting cancer in a 70-year-old man. Histological analysis excluded neoplasia, and bacteriological culture excluded tuberculosis. Serological testing and PCR Francisella were positive for this hunter patient, then treated by ciprofloxacin with a favourable outcome.

Infective endocarditis: does a new 16S rDNA set of primers improve the microbiological diagnosis?

BACKGROUND

In infective endocarditis (IE), blood cultures are negative in 2.5-31% of cases because of a previously prescribed antimicrobial treatment. Molecular methods may represent an alternative to conventional microbiological techniques to identify the causative agent. The aim of this prospective study was to evaluate the performance of a new primer pair (341F/785R) for 16S rDNA amplification in heart valves compared with primers 91E/13BS already used for the diagnosis of IE. The primer pair 341F/785R was previously selected in silico to allow 16S rDNA amplification for a large coverage of bacterial species.

RESULTS

A total of 74 patients suspected of having IE were included in this study. IE was diagnosed in 55 of these patients using the modified Duke criteria, which was the gold standard here. 91E/13BS primers were more sensitive than 341F/785R primers: 38/55 (69.1%) samples were positive using 91E/13BS primers against 28/55 (50.9%) with 341F/785R (p = 0.013). When at least one of the two molecular methods was positive, the sensitivity and specificity of 16S rDNA amplification was 72.7% and 94.7%, respectively.

CONCLUSION

Even if the new primer pair 341F/785R seemed promising in silico, it was less sensitive for 16S rDNA amplification in heart valves than the 91E/13BS pair already used. This study underlines a lack of standardization for 16S rDNA amplification for clinical samples.

Wide-pulse-high-frequency neuromuscular electrical stimulation in cerebral palsy

OBJECTIVE

The present study assesses whether wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation (NMES) could result in extra-force production in cerebral palsy (CP) patients as previously observed in healthy individuals.

METHODS

Ten CP and 10 age- and sex-matched control participants underwent plantar flexors NMES. Two to three 10-s WPHF (frequency: 100 Hz, pulse duration: 1 ms) and conventional (CONV, frequency 25 Hz, pulse duration: 50 μs) trains as well as two to three burst-like stimulation trains (2s at 25 Hz, 2s at 100 Hz, 2s at 25 Hz; pulse duration: 1 ms) were evoked. Resting soleus and gastrocnemii maximal H-reflex amplitude (Hmax) was normalized by maximal M-wave amplitude (Mmax) to quantify α-motoneuron modulation.

RESULTS

Similar Hmax/Mmax ratio was found in CP and control participants. Extra-force generation was observed both in CP (+18 ± 74%) and control individuals (+94 ± 124%) during WPHF (p<0.05). Similar extra-forces were found during burst-like stimulations in both groups (+108 ± 110% in CP and +65 ± 85% in controls, p>0.05).

CONCLUSION

Although the mechanisms underlying extra-force production may differ between WPHF and burst-like NMES, similar increases were observed in patients with CP and healthy controls.

SIGNIFICANCE

Development of extra-forces in response to WPHF NMES evoked at low stimulation intensity might open new possibilities in neuromuscular rehabilitation.

A descriptive analysis of the upper limb patterns during gait in individuals with cerebral palsy

Patients with cerebral palsy (CP) are characterized by a large diversity of gait deviations; thus, lower limb movements during gait have been well-analyzed in the literature. However, the question of upper limb movements and, more particularly, arm movements during gait has received less attention for CP patients as a function of the disease type (Hemiplegic, HE or Diplegic, DI). Thus, the aim of this study was to investigate upper limb movements for a large group of CP patients; we used a retrospective search, including upper limb kinematic parameters and 92 CP patients (42 females and 50 males, mean±standard deviation (SD); age: 15.2±6.7 years). The diagnoses consisted of 48 HE and 44 DI. A control group of 15 subjects (7 females and 8 males, age: 18.4±8.4 years) was included in the study to provide normal gait data. For the DI patients and CG, 88 arms and 30 arms were analyzed, respectively. For the HE patients, 48 affected arms and 48 non-affected arms were analyzed. The kinematic parameters selected and analyzed were shoulder elevation angles; elbow flexion angles; thorax tilt and obliquity angles; hand vertical and anterior-posterior movements; and arm angles. Several gait parameters were also analyzed, such as the gait profile score (GPS) and normalized speed. Statistical analyses were performed to compare CG with the affected and non-affected upper limbs of HE patients and with the two upper limbs of DI patients. The results show that HE and DI patients adopt abnormal upper limb movements. However, DI patients have greater shoulder, elbow, thorax and arm angle movements compared with HE patients. However, HE patients adopt different movements between their affected and non-affected arms. Thus, the patients used their upper limbs to optimize their gait more where gait deviations were more important. These observations confirm that the upper limbs must be integrated into rehabilitation programs to improve inter-limb coordination.

Gait abnormalities in obstructive sleep apnea and impact of continuous positive airway pressure

We aimed to determine the effect of continuous positive airway pressure (CPAP) on gait in obstructive sleep apnea (OSA) patients. Gait during single and dual tasks was recorded in 15 OSA patients at baseline and after 8 weeks of CPAP therapy. Step and stance time improved after CPAP. We showed a specific dual-task effect in the condition of verbal fluency. Eight weeks of CPAP seems to improve gait of OSA patients that are specifically disturbed by the dual task of verbal fluency.

First evaluation of drug-resistant Mycobacterium tuberculosis clinical isolates from Congo revealed misdetection of fluoroquinolone resistance by line probe assay due to a double substitution T80A-A90G in GyrA

Background

Tuberculosis (TB) is one of the major public health problems in Congo. However, data concerning Mycobacterium tuberculosis drug resistance are lacking because of the insufficient processing capacity. So, the aim of this study was to investigate for the first time the resistance patterns and the strain lineages of a sample of M. tuberculosis complex (MTBC) isolates collected in the two main cities of Congo.

Methods

Over a 9-day period, 114 smear-positive sputa isolated from 114 patients attending centers for the diagnosis and treatment of TB in Brazzaville and Pointe Noire were collected for culture and drug susceptibility testing (DST). Detection of mutations conferring drug resistance was performed by using line probe assays (GenoType MTBDRplus and MTBDRsl) and DNA sequencing. Strain lineages were determined by MIRU-VNTR genotyping.

Results

Of the 114 sputa, 46 were culture positive for MTBC. Twenty-one (46%) were resistant to one or more first-line antiTB drugs. Of these, 15 (71%) were multidrug resistant (MDR). The most prevalent mutations involved in rifampin and isoniazid resistance, D516V (60%) in rpoB and S315T (87%) in katG respectively, were well detected by MTBDRplus assay. All the 15 MDR strains were susceptible to fluoroquinolone and injectable second-line drug. No mutation was detected in the rrs locus involved in resistance to amikacin and capreomycin by both the MTBDRsl assay and DNA sequencing. By contrast, 9 MDR strains belonging to the same cluster related to T-family were identified as being falsely resistant to fluoroquinolone by the MTBDRsl assay due to the presence of a double substitution T80A-A90G in GyrA.

Conclusions

Taken together, these data revealed a possible spread of a particular MDR clone in Congo, misidentified as fluoroquinolone resistant by MTBDRsl assay. Thus, this test cannot replace gold-standard culture method and should be interpreted carefully in view of the patient's native land.

CGTase-catalysed cis-glucosylation of L-rhamnosides for the preparation of Shigella flexneri 2a and 3a haptens

We report the enzymatic synthesis of α-D-glucopyranosyl-(1→4)-α-L-rhamnopyranoside and α-D-glucopyranosyl-(1→3)-α-L-rhamnopyranoside by using a wild-type transglucosidase in combination with glucoamylase and glucose oxidase. It was shown that Bacillus circulans 251 cyclodextrin glucanotransferase (CGTase, EC 2.1.4.19) can efficiently couple an α-L-rhamnosyl acceptor to a maltodextrin molecule with an α-(1→4) linkage, albeit in mixture with the α-(1→3) regioisomer, thus giving two glucosylated acceptors in a single reaction. Optimisation of the CGTase coupling reaction with β-cyclodextrin as the donor substrate and methyl or allyl α-L-rhamnopyranoside as acceptors resulted in good conversion yields (42-70%) with adjustable glycosylation regioselectivity. Moreover, the efficient chemical conversion of the products of CGTase-mediated cis-glucosylation into protected building blocks (previously used in the synthesis of O-antigen fragments of several Shigella flexneri serotypes) was substantiated. These novel chemoenzymatic strategies towards useful, convenient intermediates in the synthesis of S. flexneri serotypes 2a and 3a oligosaccharides might find applications in developments towards synthetic carbohydrate-based vaccine candidates against bacillary dysentery.

Identification of gait patterns in individuals with cerebral palsy using multiple correspondence analysis

Great importance has been placed on the development of gait classification in cerebral palsy (CP) to assist clinicians. Nevertheless, gait classification is challenging within this group because the data is characterized by a high-dimensionality and a high-variability. Thus, the aim of this study was to analyze without a priori, a database of clinical gait analysis (CGA) of CP patients, using multiple correspondence analysis (MCA). A retrospective search, including biomechanical and clinical parameters was done between 2006 and 2012. One hundred and twenty two CP patients were included in this study (51 females and 71 males, mean age ± SD: 14.2 ± 7.5 years). Sixteen biomechanical spatio-temporal and kinematic parameters were included in the analysis. This data was transformed by a fuzzy window coding based on the distribution of each parameter in three modalities: low, average and high. Afterward, a MCA was used to associate parameters and to define classes. From this, seven most explicative gait parameters used to characterize gait of CP patients were identified: maximal hip extension, hip range, knee range, maximal knee flexion at initial contact, time of peak knee flexion, and maximal ankle dorsiflexion in stance phase and in swing phase. Moreover, four main profiles of CP patients have been defined from the multivariate approach: an apparent equinus gait group (the most similar of the control group with diplegic and hemiplegic patients with a GMFCS 1), a true equinus gait group (the youngest group with diplegic and some hemiplegic patients with a GMFCS 1), a crouch gait group (the oldest group with a majority of diplegic and rare hemiplegic patients with a GMFCS 2) and a jump knee gait group (the greatest level of global spasticity of the lower limbs with a majority of diplegic and rare hemiplegic patients with a GMFCS 2). Thus, this study showed the feasibility of the MCA in order to characterize and classify a large database of CP patients.

Oligosaccharide biosensor for direct monitoring of enzymatic activities using QCM-D

Enzymatic modification of saccharidic biomass is a subject of intensive research with potential applications in plant or human health, design of biomaterials and biofuel production. Bioengineering and metagenomics provide access to libraries of glycoside hydrolases but the biochemical characterization of these enzymes remains challenging, requiring fastidious colorimetric tests in discontinuous assays. Here, we describe a highly sensitive carbohydrate biosensor for the detection and characterization of glycoside hydrolases. Immobilization of oligosaccharides was achieved using copper-catalyzed azide-alkyne cycloaddition of maltoheptaose-modified probes onto self-assembled monolayers bearing azide reactive groups. This biosensor allowed detection of glycoside hydrolase activities at the picomolar level using quartz-crystal microbalance with dissipation monitoring (QCM-D). To our knowledge, this protocol provides the best performance to date for the detection of glycoside hydrolase activities. For each enzyme tested, we could determine the kinetic constant from the QCM-D data, and derive conclusions that correlated well with those of standard colorimetric tests. This opens the way to a new generation of rapid and direct tests characterizing functionally carbohydrate-active enzymes.

Associations between gait and clinical parameters in patients with severe knee osteoarthritis: a multiple correspondence analysis

BACKGROUND

Given the complexity of the gait of patients with knee osteoarthritis, a multiple correspondence analysis may be helpful to optimise the extraction of relevant gait and clinical information. Therefore, the aims of this study are to identify the main associations with clinical and gait biomechanical parameters and to evaluate whether there are more specific knee osteoarthritis groups with different gait profiles.

METHODS

Ninety patients with severe knee osteoarthritis and twenty-six healthy individuals participated in this study. Pain and function were assessed with the WOMAC Index; knee joint deformity was assessed by the hip-knee-ankle angle on full-limb radiography; and full body gait analysis was performed with a motion analysis system and force plates.

FINDINGS

Using multiple correspondence analysis, two categories of gait parameters that best explain the gait variance of patients with knee osteoarthritis were highlighted. The forward displacement category is composed of the parameters speed, stride length, hip flexion and knee flexion. The frontal category is composed of the parameters thorax obliquity and knee adductor moments. Moreover, based on these parameters, four distinct gait profiles were identified: two gait profiles were associated with knee varus deformities, increased thorax obliquity and different forward displacements, while two gait profiles were associated with valgus deformities and different forward displacements.

INTERPRETATION

These gait parameters can be used to simplify the characterisation of the gait of the knee osteoarthritis population. Patients in varus profiles increase thorax obliquity on the stance limb and may reduce forward displacement. Patients in valgus profiles, however, only reduce forward displacement.

Full body gait analysis may improve diagnostic discrimination between hereditary spastic paraplegia and spastic diplegia: a preliminary study

Hereditary spastic paraplegia (HSP) and spastic diplegia (SD) patients share a strong clinical resemblance. Thus, HSP patients are frequently misdiagnosed with a mild form of SD. Clinical gait analysis (CGA) has been highlighted as a possible tool to support the differential diagnosis of HSP and SD. Previous analysis has focused on the lower-body but not the upper-body, where numerous compensations during walking occur. The aim of this study was to compare the full-body movements of HSP and SD groups and, in particular, the movement of the upper limbs. Ten HSP and 12 SD patients were evaluated through a CGA (VICON 460 and Mx3+; ViconPeak(®), Oxford, UK) between 2008 and 2012. The kinematic parameters were computed using the ViconPeak(®) software (Plug-In-Gait). In addition, the mean amplitude of normalised (by the patient's height) arm swing was calculated. All patients were asked to walk at a self-selected speed along a 10-m walkway. The mean kinematic parameters for the two populations were analysed with Mann-Whitney comparison tests, with a significant P-value set at 0.05. The results demonstrated that HSP patients used more spine movement to compensate for lower limb movement alterations, whereas SD patients used their arms for compensation. SD patients had increased shoulder movements in the sagittal plane (Flexion/extension angle) and frontal plane (elevation angle) compared to HSP patients. These arm postures are similar to the description of the guard position that toddlers exhibit during the first weeks of walking. To increase speed, SD patients have larger arm swings in the sagittal, frontal and transversal planes. Upper-body kinematics, and more specifically arm movements and spine movements, may support the differential diagnosis of HSP and SD.

Adapted timed up and go: a rapid clinical test to assess gait and cognition in multiple sclerosis

BACKGROUND/AIMS

To measure the Timed Up and Go (TUG), imagined TUG (iTUG), and the difference of time between these two tests (delta time) in 20 patients with relapsing-remitting multiple sclerosis (RRMS) and 20 healthy age-matched controls and to examine whether an association with cognitive functions, motor impairment, and behavioral changes can be determined.

METHODS

The mean ± SD of TUG, iTUG and delta time were used as outcomes. Spatiotemporal gait parameters were recorded by a 12-camera optoelectronic system during straight walking at usual self-selected speed. Cognitive functions were assessed by a standardized neuropsychological examination.

RESULTS

Patients performed the TUG slower than the controls (10.00 ± 1.70 s vs. 8.71 ± 1.04 s, p = 0.01, respectively). The TUG was correlated with gait parameters, cognitive functions, and behavior, whereas delta time was correlated only with cognitive functions.

CONCLUSION

TUG represents an interesting test to reveal subtle deficits in RRMS patients with low disability and is related to motor, cognitive, and behavioral functioning. Combining with the TUG, delta time could easily give additional information on specific cognitive functions in the assessment of patients with RRMS.

Interest of dual-task-related gait changes in idiopathic normal pressure hydrocephalus

BACKGROUND

  Gait disorders in patients with idiopathic normal pressure hydrocephalus (iNPH) share similar characteristics found in pathologies presenting with higher-level gait disorders that have been specifically associated with gait changes during walking while simultaneously performing an attention-demanding task (i.e. dual tasking). The current study assessed the effect of cerebrospinal fluid (CSF) tapping on quantitative gait modification during single and dual tasking in patients with a suspicion of iNPH.

METHODS

  Of 53 patients suspected of iNPH, 18 have been included in this study. Gait analysis during single- and dual-task condition (walking and backward counting) before and after tapping of 40 ml CSF has been performed.

RESULTS

  Gait speed (P < 0.01) and stride length (P < 0.05) were significantly improved during dual-task conditions after CSF tapping compared to the gait performance before spinal tapping, without such improvement for gait parameters during single-tasking.

CONCLUSION

  Dual-tasking condition better reveals gait improvement after CSF tapping than single-tasking in patients suspected of iNPH.

An exercise intervention to improve diabetic patients' gait in a real-life environment

AIMS

Gait characteristics and balance are altered in diabetic individuals. Little is known about possible treatment strategies. This study evaluated the effect of a specific training program on diabetic patients' gait.

METHODS

A randomized controlled trial (N=71) with an intervention (IG) (N=35), and control group (CG) (N=36). The intervention consisted of physiotherapeutic group training including gait and balance exercises with function-oriented strengthening. Controls received no treatment.

RESULTS

After intervention the IG increased their habitual walking speed by 0.149ms(-1) (0.54kmh(-1)) on tarred terrain and by 0.169ms(-1) (0.61kmh(-1)) on the cobblestones. This significant treatment effect (p<0.001) decreased slightly at the six-month follow-up, but remained significant (p<0.001). In a similar manner, significant improvement was observed for cadence, gait cycle time and stance time on both terrains. All outcomes except stance time on the tarred terrain remained significant at the six-month follow-up. No significant effect was observed for stride length and the coefficient of variation of gait cycle time (on either surface) at the corrected significance level of p<0.004. CG patients' parameters all remained unchanged or progressively deteriorated compared to baseline values.

DISCUSSION

Cadence contributed 80%, whereas stride length only contributed 20% to the change of gait velocity. This may be due to the treatment or to diabetic patients' potential to regulate their cadence and stride length.

CONCLUSION

A specific training program can improve diabetic patients' gait in a real life environment. A challenging environment highlights treatment effects on patients' gait better than an evenly tarred surface.

The gait and balance of patients with diabetes can be improved: a randomised controlled trial

AIMS/HYPOTHESIS

Gait characteristics and balance are altered in diabetic patients. Little is known about possible treatment strategies. This study evaluates the effect of a specific training programme on gait and balance of diabetic patients.

METHODS

This was a randomised controlled trial (n=71) with an intervention (n=35) and control group (n=36). The intervention consisted of physiotherapeutic group training including gait and balance exercises with function-orientated strengthening (twice weekly over 12 weeks). Controls received no treatment. Individuals were allocated to the groups in a central office. Gait, balance, fear of falls, muscle strength and joint mobility were measured at baseline, after intervention and at 6-month follow-up.

RESULTS

The trial is closed to recruitment and follow-up. After training, the intervention group increased habitual walking speed by 0.149 m/s (p<0.001) compared with the control group. Patients in the intervention group also significantly improved their balance (time to walk over a beam, balance index recorded on Biodex balance system), their performance-oriented mobility, their degree of concern about falling, their hip and ankle plantar flexor strength, and their hip flexion mobility compared with the control group. After 6 months, all these variables remained significant except for the Biodex sway index and ankle plantar flexor strength. Two patients developed pain in their Achilles tendon: the progression for two related exercises was slowed down.

CONCLUSIONS/INTERPRETATION

Specific training can improve gait speed, balance, muscle strength and joint mobility in diabetic patients. Further studies are needed to explore the influence of these improvements on the number of reported falls, patients' physical activity levels and quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00637546

FUNDING

This work was supported by the Swiss National Foundation (SNF): PBSKP-123446/1/

Investigation of standing balance in diabetic patients with and without peripheral neuropathy using accelerometers

BACKGROUND

Peripheral neuropathy is recognised to be the most symptomatic complication of diabetes and is also linked to postural instability. This study investigates balance instability in diabetic patients with and without peripheral neuropathy.

METHODS

Quiet standing balance was investigated using an accelerometric-based method in 24 diabetic patients (12 with and 12 without peripheral neuropathy) and compared with 12 control subjects. Accelerations were measured at lumbar and ankle levels using three accelerometers. Two standing conditions of 30s were evaluated (i.e., eyes opened, eyes closed). The range and root mean square values were calculated on the anterior posterior component of lumbar and ankle accelerations and for the medial lateral component of lumbar accelerations. Differences between parameters were compared between groups using ANOVA and post hoc comparisons.

FINDINGS

The diabetic patients with peripheral neuropathy show higher-range and root mean square values compared with those of control subjects and diabetic patients without peripheral neuropathy. Significant differences between groups have been detected for anterior posterior range of lumbar acceleration, which was significantly higher for diabetic patients with peripheral neuropathy, compared with those of others groups. Significant higher values for diabetic patients with peripheral neuropathy were also detected for anterior posterior range and root mean square of ankle accelerations compared with control subjects. Visual deprivation shows an increase in accelerometric parameters for each group.

INTERPRETATION

This study is the first to investigate the balance instability of diabetic patients using accelerometers. Results confirm that diabetic patients with peripheral neuropathy have greater postural instability with higher acceleration values than those of control group and diabetic patients without peripheral neuropathy.

Clinical factors associated with gait alterations in diabetic patients

AIM

To identify clinical factors associated with gait alterations in patients with Type 2 diabetes.

METHODS

A sample of 76 diabetic patients underwent clinical examination and an outdoor gait assessment on tarred and cobblestoned terrains. We calculated respective differences in gait speed (performance measure) and gait variability (fall risk index) on changing terrains. Associations with clinical factors were investigated using correlation coefficients and linear regression analysis.

RESULTS

The mean walking speed on the tarred pathway was 4.5 +/- 0.6 km/h and 3.9 +/- 0.8 km/h on the cobblestone pathway (P < 0.001). The CVGCT increased from 2.6 +/- 0.9% on the tarred pathway to 5.1 +/- 2.8% on the cobblestone pathway (P < 0.001). Regression analysis showed that 36% of the decrease in gait speed was explained proportionally by the mean of maximal isometric lower limb strength (22.2%; P < or = 0.01), fear of falls (7.4%; P < or = 0.01) and participants' perceived vibration threshold (6.4%; P < or = 0.01). Moreover, mean maximal isometric strength explained 11.8% (P < or = 0.01) of the increase of the coefficient of variation of the gait cycle time when participants changed from tarred terrain to cobblestones.

CONCLUSION

This study indicated that both physiological (strength and proprioception) and cognitive-behavioural factors (fear of falls) should be considered when treating diabetic patients with gait alterations. Therapists should apply these findings when developing specific fall prevention and treatment programmes.

Reliability of diabetic patients' gait parameters in a challenging environment

Activities of daily life require us to move about in challenging environments and to walk on varied surfaces. Irregular terrain has been shown to influence gait parameters, especially in a population at risk for falling. A precise portable measurement system would permit objective gait analysis under such conditions. The aims of this study are to (a) investigate the reliability of gait parameters measured with the Physilog in diabetic patients walking on different surfaces (tar, grass, and stones); (b) identify the measurement error (precision); (c) identify the minimal clinical detectable change.

METHODS

16 patients with Type 2 diabetes were measured twice within 8 days. After clinical examination patients walked, equipped with a Physilog, on the three aforementioned surfaces.

RESULTS

ICC for each surface was excellent for within-visit analyses (>0.938). Inter-visit ICC's (0.753) were excellent except for the knee range parameter (>0.503). The coefficient of variation (CV) was lower than 5% for most of the parameters. Bland and Altman Plots, SEM and SDC showed precise values, distributed around zero for all surfaces.

DISCUSSION

Good reliability of Physilog measurements on different surfaces suggests that Physilog could facilitate the study of diabetic patients' gait in conditions close to real-life situations. Gait parameters during complex locomotor activities (e.g. stair-climbing, curbs, slopes) have not yet been extensively investigated.

CONCLUSION

Good reliability, small measurement error and values of minimal clinical detectable change recommend the utilization of Physilog for the evaluation of gait parameters in diabetic patients.

Gait characteristics of diabetic patients: a systematic review

Patients with diabetes are at higher risk of experiencing fall-related injuries when walking than healthy controls. The underlying mechanism responsible for this is not yet clear. Thus we intend to summarize diabetic patients' gait characteristics and emphasize those which could be the possible underlying mechanisms for increased fall risk. This systematic review aims, in particular, to: (1) evaluate the quality of existing studies which investigate the gait characteristics of diabetic patients, (2) highlight areas of agreement and contradiction in study results, (3) discuss and emphasize parameters associated with fall risk, and (4) propose new orientations and further domains for research needed for their fall risk prevention. We conducted an electronic search of Pedro, PubMed, Ovid and Cochrane. Two authors independently assessed all abstracts. Quality of the selected articles was scored, and the study results summarized and discussed. We considered 236 abstracts of which 28 entered our full text review. Agreement on data quality between two reviewers was high (kappa: 0.90). Authors investigating gait parameters in a diabetic population evaluated in particular parameters either associated with fall risk (speed, step length or step-time variability) or with ulcers (pressure). There is agreement that diabetic patients walk slower, with greater step variability, and present higher plantar pressure than healthy controls. We concluded that diabetic patients present gait abnormalities, some of which can lead to heightened fall risk. To understand its' underlying mechanisms, and to promote efficient prevention, further studies should analyse gait under 'real-life' conditions.

Unexpected regioselectivity of Humicola insolens Cel7B glycosynthase mutants

Four Humicola insolens Cel7B glycoside hydrolase mutants have been evaluated for the coupling of lactosyl fluoride on O-allyl N(I)-acetyl-2(II)-azido-beta-chitobioside. Double mutants Cel7B E197A H209A and Cel7B E197A H209G preferentially catalyze the formation of a beta-(1-->4) linkage between the two disaccharides, while single mutant Cel7B E197A and triple mutant Cel7B E197A H209A A211T produce predominantly the beta-(1-->3)-linked tetrasaccharide. This result constitutes the first report of the modulation of the regioselectivity through site-directed mutagenesis for an endoglycosynthase.

Java project on periodontal diseases. The natural development of periodontitis: risk factors, risk predictors and risk determinants

OBJECTIVE

To identify risk factors, risk predictors and risk determinants for onset and progression of periodontitis.

MATERIAL AND METHODS

For this longitudinal, prospective study all subjects in the age range 15-25 years living in a village of approximately 2000 inhabitants at a tea estate on Western Java, Indonesia, were selected. Baseline examination was carried out in 1987 and follow-up examinations in 1994 and 2002. In 2002, 128 subjects could be retrieved from the original group of 255. Baseline examination included evaluation of plaque, bleeding on probing, calculus, pocket depth, attachment loss and presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, spirochetes and motile microorganisms.

RESULTS

The mean attachment loss increased from 0.33 mm in 1987 to 0.72 mm in 1994 and 1.97 mm in 2002. Analysis identified the amount of subgingival calculus and subgingival presence of A. actinomycetemcomitans as risk factors, and age as a risk determinant, for the onset of disease. Regarding disease progression, the number of sites with a probing depth > or = 5 mm and the number of sites with recession were identified as risk predictors and male gender as a risk determinant.

CONCLUSION

Screening of these parameters early in life could be helpful in the prevention of onset and progression of periodontal diseases.