Detection of qacΔE Efflux Pump Gene among the Clinical Isolates of Escherichia coli and its Correlation with Resistance to Disinfectants.

BACKGROUND: Disinfectants and antiseptics inhibit the dissemination of pathogenic organisms in hospitals but often cause disinfectant-resistant microorganisms, an important factor for nosocomial infection. This study aimed to evaluate the correlation between qacΔE efflux pump gene and its resistance to disinfectants among Escherichia coli clinical isolates. METHODS: A total of 97 E. coli isolates were isolated from patients with urinary tract infections. The minimum inhibition concentration (MIC) value of chlorhexidine and benzalkonium chloride was determined using broth microdilution method. Effect of efflux pumps was assessed by MIC test in the presence of phenylalanine-arginine ß-naphthylamide (PAßN), and then the qacΔE efflux pump gene was detected using polymerase chain reaction (PCR). RESULT: Of the isolates, 85.6% and 61.9% were resistant to chlorhexidine and benzalkonium chloride, respectively. Following the treatment of isolates with the efflux pump's inhibitor, PAßN, the MIC value of chlorhexidine and benzalkonium chloride decreased in 75.2% and 57.7% of the isolates, respectively. A significant correlation was found between PAßN treatment and the change in the resistant strains to susceptible strains (p = 0.021). The qacΔE gene was detected in 84.5% (n = 82) of the isolates, and the presence of the gene amongst disinfectant-resistant strains was also significant (p < 0.001). CONCLUSIONS: It is suggested to conduct other studies on other efflux pumps, as well as to periodically monitor the resistance to disinfectants. Substances inhibiting efflux pumps and neutral compounds are effective in the reduction of resistance to disinfectants. New disinfectants and drugs should be designed.

Bilateral Asymmetry in Knee and Hip Musculoskeletal Loading During Stair Ascending/Descending in Individuals with Unilateral Mild-to-Moderate Medial Knee Osteoarthritis.

Most cases of unilateral knee osteoarthritis (OA) progress to bilateral OA within 10 years. Biomechanical asymmetries have been implicated in contralateral OA development; however, gait analysis alone does not consistently detect asymmetries in OA patient gait. Stair ambulation is a more demanding activity that may be more suited to reveal between-leg asymmetries in OA patients. The objective of this study was to investigate the between-leg biomechanical differences in patients with unilateral mild-to-moderate knee OA. Sixteen unilateral mild-to-moderate medial knee OA patients and 16 healthy individuals underwent kinematic and kinetic analysis of stair ascent and descent. Stair ascent produced higher loading and muscle forces in the unaffected limb compared to the OA limb, and stair descent produced lower loading on the OA limb compared to healthy subjects. These biomechanical differences were apparent in the ankle, knee, and hip joints. The implications of these findings are that OA patients rely more heavily on their unaffected sides than the affected side in stair ascent, a strategy that may be detrimental to the unaffected joint health. The reduction in affected limb loading in stair descent is thought to be related to minimizing pain.

Characterization of muscle recruitment during gait of bilateral transfemoral and through-knee persons with limb loss.

Introduction: Due to loss in musculoskeletal capacity, there is an increased burden on the residual limbs of bilateral transfemoral and through-knee persons with limb loss. This reduced capacity is associated with an increased cost of walking that is detrimental to functionality. Compensatory gait strategies are adopted by this population. However, how these strategies relate to specific muscle recruitment is not known. The primary aim of this study is to characterize muscle recruitment during gait of this population. The secondary aim is to assess whether the measured kinematics can be actuated when the endurance of specific muscles is reduced and if this is the case, which alternative muscles facilitate this. Methods: 3D gait data and high-resolution magnetic resonance images were acquired from six bilateral transfemoral and through-knee persons with limb loss. Subject-specific anatomical muscle models were developed for each participant, and a validated musculoskeletal model was used to quantify muscle forces in two conditions: during normal gait (baseline) and when muscles, which were identified as functioning above a "healthy" level at baseline, have a reduced magnitude of maximum force capacity (reduced endurance simulation). To test the hypothesis that there are differences in muscle forces between the baseline trials and the simulations with reduced muscular endurance, a Bonferroni corrected two-way ANOVA with repeated measures was completed between the two states. Results: The baseline analysis showed that the hip flexors experience relatively high muscle activations during gait. The reduced endurance simulation found two scenarios. First, for 5 out of the 12 simulations, the baseline kinematics could not be reproduced with the reduced muscular capacity. Second, for 7 out of 12 cases where the baseline kinematics were achieved, this was possible with compensatory increased activation of some muscles with similar functions (p ≤ 0.003). Discussion: Evidently, due to the loss of the ankle plantar flexors, gait imposes a high demand on the flexor muscle group of the residual limb. This study highlights how the elevated cost of gait in this population manifests in muscle recruitment. To enhance functionality, it is critical to consider the mechanical demand on the hip flexors and to develop rehabilitation interventions accordingly.

High tibiofemoral contact and muscle forces during gait are associated with radiographic knee OA progression over 3 years.

BACKGROUND: The objective of this study was to investigate differences in tibiofemoral joint contact forces between individuals with moderate medial OA who exhibit radiographic knee OA progression within 3 years versus those who do not, and to understand the relationship between model-predicted contact forces and net external moments for this population. METHODS: 27 individuals with moderate medial compartment knee OA underwent baseline instrumented gait analysis. OA progressors were defined as those who experienced at least a one grade increase in medial joint space narrowing at three years. An electromyography-driven musculoskeletal model was used to estimate muscle and tibiofemoral contact forces at baseline, which were compared between progressors and non-progressors using t-tests. RESULTS: Seven individuals experienced radiographic OA progression by 3 years. Progressors walked with significantly higher peaks of medial and total tibiofemoral contact forces, and higher impulse of medial contact forces. Significant and high correlations were found between: first peaks of medial and total contact forces with first peak of the knee adduction moment (R2 = 0.74; R2 = 0.59); second peaks of medial and total knee contact forces with second peaks of knee adduction and flexion moments (R2 = 0.71; R2 = 0.68); medial knee contact force impulse with knee adduction moment impulse (R2 = 0.76). CONCLUSIONS: Higher tibiofemoral joint contact forces during walking were associated with three-year radiographic knee OA progression based on medial joint space narrowing. These results support the need for strategies that reduce compressive knee contact forces through the reduction of adduction and flexion moments during walking.

Antibacterial activity of chitosan-based nanohybrid membranes against drug-resistant bacterial isolates from burn wound infections.

Biocompatible and non-toxic properties of chitosan make it a candidate with excellent application prospects in developing wound dressing conjugate compounds. Six different chitosan-based nanohybrid membranes were evaluated against multidrug-resistant bacterial isolates. Different combinations of chitosan, ciprofloxacin (CIP), biofunctionalized montmorillonite (MMT), and montmorillonite with sulfate chains (SMMT) were provided, and their antibacterial activity was assessed using the colony count method. Totally, 27 drug-resistant isolates, including 6x methicillin-resistant Staphylococcus aureus, 7 vancomycin-resistant Enterococcus faecalis, 4 Acinetobacter baumannii, and 10 Pseudomonas aeruginosa isolates were identified from burn wound infections. Chitosan and montmorillonite did not show significant antibacterial effect (p > 0.05), but chitosan/SMMT/CIP was the most effective nanocomposite (p < 0.01). Chitosan-based nanocomposites with ciprofloxacin could effectively reduce the susceptibility of drug-resistant bacterial isolates. Bacterial targeting using nanosystems provides an opportunity for effective antibiotic treatment by improving antibacterial efficacy.

Identification of human balance control responses to visual inputs using virtual reality.

Human upright balance is maintained through feedback mechanisms that use a variety of sensory modalities. Vision senses information about the position and velocity of the visual surround motion to improve balance by reducing the sway evoked by external disturbances. This study characterized the effects of visual information on human anterior-posterior body sway in upright stance by presenting perturbations through a virtual reality system. This made it possible to use a new visual perturbation signal, based on trapezoidal velocity pulses, whose amplitude and velocity could be controlled separately. To date, the influences of visual field position and velocity have only been studied independently due to the experimental limitations. The hip displacement, ankle torques, shank angles, and surface EMGs of four major ankle muscles were measured bilaterally as outputs. We found that the root mean square (RMS) hip displacement (body angle) increased systematically with visual input amplitude. However, for each amplitude, the RMS body angle increased when input velocity was changed from 2 to 5 degrees per second (dps) and then decreased from 5 to 10 dps. Spectral analysis was used to compute frequency response over a frequency range from 0.04 to 0.6 Hz. The gain of body sway relative to the perturbation increased with frequency, whereas the coherence declined. Moreover, as the stimulus amplitude increased, the gain generally decreased, whereas the mean coherence values always increased. The mean gains and mean coherence values were greatest for the velocity of 5 dps. This study presents a novel experimental approach to study human postural control and augments our knowledge of how visual information is processed in the central nervous system to maintain balance.NEW & NOTEWORTHY In this paper, we developed a new methodological approach to study the effects of visual information on dynamic body sway. We used VR to apply visual perturbations to induce AP body sway. We designed a new visual stimulus waveform based on trapezoidal velocity pulses whose peak-to-peak amplitude and velocity could be modulated independently. Subsequently, we investigated how the amplitude and velocity of visual field motion influence the postural responses evoked in healthy adults.

Prediction of in vivo hip contact forces during common activities of daily living using a segment-based musculoskeletal model.

Background: Quantifying in vivo hip muscle and contact forces during activities of daily living (ADL) provides valuable information for diagnosis and treatment of hip-related disorders. The objective of this study was to utilize Freebody, a segment-based musculoskeletal model, for the prediction of hip contact forces using a novel objective function during seven common ADLs and validate its performance against the publicly available HIP98 dataset. Methods: Marker data, ground reaction forces, and hip contact forces during slow, normal, and fast walking, stair ascent and descent, and standing up and sitting down were extracted for 3 subjects from the HIP98 dataset. A musculoskeletal anatomical dataset was scaled to match the dimensions of each subject, and muscle and hip contact forces were estimated by minimizing a novel objective function, which was the summation of the muscle stresses squared and body weight-normalised hip contact force. The accuracy of predictions were quantified using several metrics, and muscle forces were qualitatively compared to experimental EMGs in the literature. Results: FreeBody predicted the hip contact forces during the ADLs with encouraging accuracy: The root mean squared error of predictions were 44.0 ± 8.5, 47.4 ± 6.5, and 59.8 ± 7.1% BW during slow, normal, and fast walking, 44.2 ± 16.8% and 53.3 ± 12.2% BW for stair ascent and descent, and 31.8 ± 8.2% and 17.1 ± 5.0% BW for standing up and sitting down, respectively. The error in prediction of peak hip contact forces were 14-18%, 24-28%, 17-35% for slow, normal, and fast walking, 7-25% and 15-32% in stair ascent and descent, and around 10% for standing up and sitting down. The coefficient of determination was larger than 0.90 in all activities except in standing up (0.86 ± 0.08). Conclusion: This study has implemented a novel objective function in a segment-based musculoskeletal model, FreeBody, for the prediction of hip contact forces during a large range of ADLs. The model outputs compare favourably for all ADLs and are the best in standing up and sitting down, while muscle activation patterns are consistent with experimental EMGs from literature. This new objective function addresses one of the major limitations associated with musculoskeletal models in the literature, namely the high non-physiological predicted hip joint contact forces.

Identification of Central and Stretch Reflex Contributions to Human Postural Control.

Human postural control requires continuous modulation of ankle torque to stabilize the upright stance. The torque is generated by two components: active contributions, due to central control and stretch reflex, and passive mechanisms, due to joint intrinsic stiffness. Identifying the contribution of each component is difficult, since their effects appear together, and standing is controlled in closed-loop. This article presents a novel multiple-input, single-output method to identify central and stretch reflex contributions to human postural control. The model uses ankle muscle EMGs as inputs and requires no kinematic data. Application of the method to data from nine subjects during standing while subjected to perturbations of ankle position demonstrated that active torque accounted for 84.0± 5.5% of the ankle torque. The ankle plantar-flexors collectively produced the largest portion of the active torque through central control, with large inter-subject variability in the relative contributions of the individual muscles. In addition, reflex contribution of the plantar-flexors was substantial in half of the subjects, showing its potentially important functional role; finally, intrinsic contributions, estimated as the residual of the model, contributed to 15% of the torque. This study introduces a new method to quantify the contributions of the central and stretch reflex pathways to postural control; the method also provides an estimate of noisy intrinsic torque with significantly increased signal to noise ratio, suitable for identification of intrinsic stiffness in standing. The method can be used in different experimental conditions and requires minimal a-priori assumption regarding the role of different pathways in postural control.

Contributions of Vision in Human Postural Control: A Virtual Reality-based Study.

During human standing, it has been previously observed that information about the position and frequency of visual surround motion improves balance by reducing sway responses to external disturbances. However, experimental limitations only allowed for independent investigation of such parameters while being incapable of providing a fully immersive experience of a real environment. The aim of this study is to investigate the effect of visual information on dynamic body sway in the human upright stance by presenting perturbations through a virtual reality (VR) system. Moreover, we designed a new perturbation signal based on trapezoidal velocity (TrapV) pulses enabling us to simultaneously examine the effects of amplitude and velocity on balance control. The experiments included four different peak-to-peak amplitudes (1-10 degrees), and three velocities (2-10 degree/sec). The body angle, ankle torques and shank angles were measured and analyzed in response to each perturbation. The results reveal that stimuli with higher amplitudes evoked larger responses, while they were initially increased and reached a peak, then decreased by increasing the motion velocity of visual surround.

Patterns of muscle activation and modulation of ankle intrinsic stiffness in different postural operating conditions.

Intrinsic stiffness describes the dynamic relationship between imposed angular perturbations to a joint and the resulting torque response, due to intrinsic mechanical properties of muscles and joint, and inertia of the limbs. Recently, we showed that ankle intrinsic stiffness changes substantially with sway in normal standing. In the present study, we documented how ankle intrinsic stiffness changes with postural operating conditions. Subjects stood on an apparatus while subjected to ankle position perturbations in five conditions: normal standing, toe-up and toe-down standing, and backward and forward lean. In each condition, ankle intrinsic stiffness was estimated while its modulation with sway was accounted for. The results demonstrated that ankle intrinsic stiffness varies widely, from 0.08 to 0.75 of critical stiffness, across postural operating conditions; however, it is always smaller than the critical stiffness. Therefore, other contributions are necessary to ensure stable standing. The mean intrinsic stiffness was highest in forward lean and lowest in backward lean. Moreover, within each operating condition, the intrinsic stiffness changed with center-of-pressure position in one of three ways, each associated with a distinct muscle activation pattern; these include 1) monotonically increasing stiffness-center of pressure relation, associated with a progressive increase in triceps surae activation, 2) decreasing-increasing stiffness-center of pressure relation, associated with initial activation of tibialis anterior and later activation of triceps surae, and 3) monotonically decreasing stiffness-center of pressure relation, associated with decreasing activation of tibialis anterior. Thus intrinsic stiffness varies greatly within and across postural operating conditions, and a correct understanding of postural control requires accounting for such variations.NEW & NOTEWORTHY Ankle intrinsic stiffness changes with sway in normal standing. We quantified such changes in different postural operating conditions and demonstrated that the intrinsic stiffness changes in a manner associated with different activation patterns of ankle plantarflexors and dorsiflexors, emerging in different operating conditions. Large modulations of the intrinsic stiffness within and across postural operating conditions show that the stiffness importance and contribution change and must be accounted for in the study of postural control.

Experimental Methods to Study Human Postural Control.

Many components of the nervous and musculoskeletal systems act in concert to achieve the stable, upright human posture. Controlled experiments accompanied by appropriate mathematical methods are needed to understand the role of the different sub-systems involved in human postural control. This article describes a protocol for performing perturbed standing experiments, acquiring experimental data, and carrying out the subsequent mathematical analysis, with the aim of understanding the role of musculoskeletal system and central control in human upright posture. The results generated by these methods are important, because they provide insight into the healthy balance control, form the basis for understanding the etiology of impaired balance in patients and the elderly, and aid in the design of interventions to improve postural control and stability. These methods can be used to study the role of somatosensory system, intrinsic stiffness of ankle joint, and visual system in postural control, and may also be extended to investigate the role of vestibular system. The methods are to be used in the case of an ankle strategy, where the body moves primarily about the ankle joint and is considered a single-link inverted pendulum.

Ankle intrinsic stiffness changes with postural sway.

In standing, the human body is inherently unstable and its stabilization requires constant regulation of ankle torque, generated by a combination of ankle intrinsic properties, peripheral reflexes, and central contributions. Ankle intrinsic stiffness, which quantifies the joint intrinsic properties, has been usually assumed constant in standing; however, there is strong evidence that it is highly dependent on the joint torque, which changes significantly with sway in stance. In this study, we examined how ankle intrinsic stiffness changes with postural sway during standing. Ten subjects stood on a standing apparatus, while subjected to pulse perturbations of ankle position. The mean torque of a short period before the start of each pulse was used as a measure of background torque. Responses with similar background torques were grouped together and used to estimate the parameters of an intrinsic stiffness model. Stiffness estimates were normalized to the critical stiffness and the background torque was transformed to the center of pressure location. We found that in most subjects, the normalized stiffness increased linearly with the movement of center of pressure towards the toes, with an average slope of 2.11 ±â€¯0.80 1/m·rad. This modulation of ankle intrinsic stiffness seems functionally appropriate, since the intrinsic stiffness increases quickly, as the center of pressure moves toward the toes and the limits of stability. These large changes of ankle intrinsic stiffness with postural sway must be incorporated in any model of stance control.

A Closed-Loop Method to Identify EMG-Torque Dynamics in Human Balance Control.

Human balance control requires continuous modulation of ankle torque by central and spinal activation of the ankle muscles combined with the intrinsic mechanical stiffness of the joint. These components appear together and cannot be measured separately. This work presents a novel multiple-input, single-output, closed-loop identification method that decomposes the ankle torque in human balance control into its central, stretch reflex, and intrinsic components. The method models separate transfer functions for each EMG-torque relation for central and stretch reflex mechanisms and estimates the ankle intrinsic torque from the residuals. The method uses only EMG measurements, requires no kinematic data, and has few parameters, resulting in robust performance. Application of the method to perturbed standing data from two healthy subjects demonstrated that the central and stretch reflex torques accounted for 80-93% of the ankle torque variation, while the intrinsic stiffness was responsible for most of the remaining torque.

Ankle intrinsic stiffness is modulated by postural sway.

Dynamic ankle stiffness, which defines the relationship between joint position and the torque acting about it, determines the joint resistance to external perturbations. The contribution of joint stiffness to stance control is usually assumed to be constant; however, the stiffness may be modulated due to the ongoing sway during stance. This paper describes the results of the direct estimation of ankle intrinsic stiffness and its modulation with background torque during stance. Three subjects stood on a standing apparatus, while subjected to pulse perturbations of ankle position. The angle of center of mass, and ankle torque and angle were measured and individual torque responses to each position perturbation were analyzed. Each response lasted 90 milliseconds, where the mean of the torque record in the first 25 milliseconds was considered as its background torque. Ensemble of the responses with similar background torques were used to estimate the joint intrinsic stiffness. The estimated parameters showed that elastic element of the ankle intrinsic stiffness varied significantly (by a factor of 3) with background torque, i.e. the higher the background torque, the higher the stiffness. Thus ankle stiffness is not constant but varies greatly with postural sway.

Correlation Between qacE and qacE∆1 Efflux Pump Genes, Antibiotic and Disinfectant Resistant Among Clinical Isolates of E.coli.

INTRODUCTION: Antiseptics and disinfectants have been used widely in hospitals and other health care settings to control the growth of microorganisms. However, some disinfectant resistant strains were reported. The objectives of our study were to evaluate correlation between the efflux pump genes, drugs and disinfectant resistant among clinical isolates of E.coli. METHODS: A total of 102 of E. coli strains were isolated from urine sample of hospitalized patients. The antibiotic susceptibility was carried out by disc diffusion method. Didecyl di-methyl ammonium chloride (DDDMAC) was used as Quaternary ammonium compound (QAC) disinfectant which was used in Heart Center Hospital. PCR reaction was carried out for detection of qacE and qac∆E efflux pump genes. RESULT: Almost all the strains had higher resistance to ampicillin, ciproflaxacin, cotrimaxazole and cephalothin. Totally 49% (n: 50) of strains were produced ESBL. Almost all the strains have MIC value between 0.00195 to 0.0078 mg/l for DDDMAC. Correlation between presence of qacE and qac∆E genes and antibiotic resistance was perceived. Presence of qacE and qac∆E genes among strains that have high disinfectant MIC value were 96.9% and 93.7% respectively. In addition, 98% of ESBL producing strains harbored qacE gene and 94% of ESBL producing strains harbored qac∆E gene. CONCLUSION: Our study indicated that there was a strong correlation between presence of qacE and qac∆E genes with resistance to some antibiotics and growth in media which contain high concentration of disinfectant. In conclusion, other mechanisms also play important role in resistant to antimicrobial agents but the role of efflux pumps in resistant to antimicrobial agents should not be neglected.

Measurement of shank angle during stance using laser range finders.

Ankle joint stiffness, the dynamic relationship between the joint angle and the torque acting about it, plays an important role in the control of upright stance. In order to identify the contribution of ankle joint stiffness to stance control, ankle joint must be perturbed externally. One way to do this is to displace the foot that will cause shank movement. For identification, the ankle angle must be measured with high accuracy, for which we need to measure both foot and shank angles. However, most motion capture systems do not have the resolution and accuracy needed to measure the small ankle joint movements that occur during stance. This paper describes a method for the high resolution measurement of ankle angle during standing that uses a laser range finder to track linear displacements, which is then used to compute shank angle with respect to the vertical. A theoretical analysis of different possible measurement configurations demonstrated that measurements of horizontal shank movement would provide the optimal resolution; a range finder with a linear resolution of 25 micros would provide an angle resolution better than 0.01 degree. We built a measurement system using this configuration and performed static and dynamic experiments that demonstrated angle measurements with a resolution of less than 0.01 degree, which outperforms other motion capture systems, such as IMUs, whose resolution is in the order of one degree. Utility of the method was then demonstrated by using it to measure shank ankle during quiet and perturbed stance. The results confirmed that the method tracks small shank movements during both quiet and perturbed conditions. Estimated shank angle then was used with the foot angle, measured with a potentiometer to obtain the ankle joint angle, needed to identify the joint stiffness.

Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa.

INTRODUCTION: Chamomile (Chamaemelum nobile) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation. METHODS: The P. aeruginosa samples were isolated from patients with different types of infection, including wound infection, septicemia, and urinary tract infection. The flowers of C. nobile were dried and the extract was removed using a rotary device and then dissolved in dimethyl sulfoxide at pH 7.4. The microdilution method was used to evaluate the minimum inhibitory concentration (MIC) of this extract on P. aeruginosa , and biofilm inhibition was assayed. RESULTS: Eighty percent of the isolated samples (16/20) could form a biofilm, and most of these were isolated from wound infections. The biofilm inhibitory concentration of the C. nobile extract was 6.25-25mg/ml, whereas the MIC was 12.5-50mg/ml. CONCLUSIONS: The anti-QS property of C. nobile may play an important role in its antibacterial activity, thus offering an additional strategy in the fight against bacterial infections. However, molecular investigation is required to explore the exact mechanisms of the antibacterial action and functions of this phytocompound.

Antibacterial, anti-swarming and anti-biofilm formation activities of Chamaemelum nobile against Pseudomonas aeruginosa

Chamomile ( Chamaemelum nobile ) is widely used throughout the world, and has anti-inflammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, flowers, fruit, and bark of Combretum albiflorum, Laurus nobilis , and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofilm formation

Performance of spinal cord injury individuals while standing with the Mohammad Taghi Karimi reciprocal gait orthosis (MTK-RGO).

Most patients with spinal cord injury use a wheelchair to transfer from place to place, however they need to stand and walk with orthosis to improve their health status. Although many orthoses have been designed for paraplegic patients, they have experienced various problems while in use. A new type of reciprocal gait orthosis was designed in the Bioengineering Unit of Strathclyde University to solve the problems of the available orthoses. Since there was no research undertaken regarding testing of the new orthosis on paraplegic subjects, this study was aimed to evaluate the new orthosis during standing of paraplegic subjects. Five paraplegic patients with lesion level between T12 and L1 and aged matched normal subjects were recruited into this study. The stability of subjects was evaluated during quiet standing and while undertaking hand tasks during standing with the new orthosis and the knee ankle foot orthosis (KAFO). The difference between the performances of paraplegic subjects while standing with both orthoses, and between the function of normal and paraplegic subjects were compared using the paired t test and independent sample t test, respectively. The stability of paraplegic subjects in standing with the new orthosis was better than that of the KAFO orthosis (p < 0.05). Moreover, the force applied on the crutch differed between the orthoses. The functional performance of paraplegic subjects was better with the new orthosis compared with normal subjects. The performance of paraplegic subjects while standing with the new orthosis was better than the KAFO. Therefore, the new orthosis may be useful to improve standing and walking in patients with paraplegia.

Determination of the influence of walking with orthosis on bone osteoporosis in paraplegic subjects based on the loads transmitted through the body.

BACKGROUND: Spinal cord injury is a damage to spinal cord that results in loss of function and mobility below the level of injury. The patients use various orthoses to improve their general health, to decrease bone osteoporosis, and to improve bone mineral density. It was controversial if how much percentage of the loads applied on an orthosis and body complex is transmitted by orthosis. Therefore, it was aimed to determine the magnitude of the loads transmitted by orthosis to find the influence of walking with orthosis on bone mineral density. METHODS: Three spinal cord injured subjects were recruited in this study. They were trained to walk with a reciprocal gait orthosis. The loads applied on the hip joint of the orthosis and body complex, anatomy and orthosis were measured by use of strain gauges and motion analysis system. FINDINGS: The mean values of the force and moments transmitted by the orthosis were significantly less than those of the complex. The mean values of adduction moment transmitted through the orthosis and body complex and by the orthosis structure were 1.06 and 0.49N·m/body weight, respectively. INTERPRETATION: As a higher percentage of loads were transmitted by body than the orthosis, it can be concluded that walking with orthosis could improve bone mineral density, due to the role of bone in transmission of the loads. Therefore, it is recommended that spinal cord injured subjects walk with an orthosis in order to reduce bone osteoporosis, especially for a long period of time.