Kinetic adaptations of the intact limb in transfemoral amputees using a microprocessor prosthetic knee.

BACKGROUND: In recent decades, high-tech prostheses, including microprocessor-controlled knee (MPK), have been developed to improve the functional abilities of lower limb amputees and to reduce gait asymmetry for the prevention of early joint degradation of the intact limb. The aim of this study was to determine the differences in joint moment and power of the intact limb of transfemoral amputees (TFAs) with an MPK compared to healthy individuals in 2 walking speed conditions. METHODS: Twenty-one TFAs with MPK and matched 21 healthy individuals performed a walking task at spontaneous and rapid self-selected speeds. Spatiotemporal gait parameters and intact limb kinetic data were recorded. RESULTS: The hip and knee moments in the frontal plane during rapid walking were not significantly higher than spontaneous walking in TFA group (respectively p = 0.08 and p = 0.48) and were lower than the control group. In the sagittal plane, the hip extensor moment in TFA was higher than the control group in the landing phase (p < 0.001 in both speed conditions). SIGNIFICANCE: The kinetics of the intact limb of active TFAs with an MPK showed a significant reduction at the knee internal abductor moment compared to the control, potentially limiting risk factors for knee osteoarthritis. However, in the sagittal plane, higher hip extensor moments could favor low-back pain appearance. Gait analysis of lower limb amputees should thus be performed to highlight these kinetic adaptations and then help to propose the most relevant rehabilitation and prevention exercises to limit the appearance of early musculoskeletal degeneration.

Transfemoral amputees adapt their gait during cross-slope walking with specific upper-lower limb coordination.

BACKGROUND: Unilateral lower limb amputees have asymmetrical gaits, particularly on irregular surfaces and slopes. It is unclear how coordination between arms and legs can adapt during cross-slope walking. RESEARCH QUESTION: How do transfemoral amputees (TFAs) adapt their upper-lower limb coordination on cross-slope surfaces? METHODS: Twenty TFA and 20 healthy adults (Ctrl) performed a three-dimensional gait analysis in 2 walking conditions: level ground and cross-slope with prosthesis uphill. Sagittal joint angles and velocities of hips and shoulders were calculated. Continuous relative phases (CRP) were computed between the shoulder and the hip of the opposite side. The closer to 0 the CRP is, the more coordinated the joints are. Curve analysis were conducted using SPM. RESULTS: The mean CRP between the downhill shoulder and the uphill hip was higher in TFA compared to Ctrl (p = 0.02), with a walking conditions effect (p = 0.005). TFA showed significant differences about the end of the stance phase (p = 0.01) between level ground and cross-slope, while Ctrl showed a significant difference (p = 0.008) between these walking conditions at the end of the swing phase. In CRP between the uphill shoulder and the downhill hip, SnPM analysis showed intergroup differences during the stance phase (p < 0.05), but not in the comparison between walking conditions in TFA and Ctrl groups. SIGNIFICANCE: TFA showed an asymmetrical coordination in level ground walking compared to Ctrl. Walking on cross-slope led to upper-lower limb coordination adaptations: this condition impacted the CRP between downhill shoulder and uphill hip in both groups. The management of the prosthetic limb, positioned uphill, induced a reorganization of the coordination with the upper limb of the amputated side. Identifying upper-lower limb coordination adaptations on cross-slope surfaces will help to achieve rehabilitation goals for effective walking in urban environments.

Walking abilities improvements are associated with pelvis and trunk kinematic adaptations in transfemoral amputees after rehabilitation.

BACKGROUND: Rehabilitation can be proposed to transfemoral amputees to improve functional abilities and limit the risk of early degeneration of the musculoskeletal system partly due to altered kinematic behavior. The main aim of this study was to assess the impact of functional rehabilitation on clinical walking tests, gait symmetry and pelvis and trunk kinematics in transfemoral amputees during overground walking. METHODS: Eleven transfemoral amputees followed a functional rehabilitation program with objectives aimed at improving walking abilities and gait symmetry. Clinical functional tests, symmetry between prosthetic and intact sides and trunk and pelvis motions were recorded before and after rehabilitation. FINDINGS: Clinical walking tests were improved after rehabilitation (p < 0.05), and step width was reduced (p = 0.04). Regarding symmetry between the single stances on the prosthesis and intact sides, only a significant decrease in trunk frontal inclination asymmetry was noted after rehabilitation (p = 0.01). Pelvic frontal obliquity was significantly increased during prosthetic (p = 0.02) and intact single stances (p = 0.005). INTERPRETATION: Our study showed a positive effect of rehabilitation on transfemoral amputees functional abilities. These improvements were associated with higher pelvic mobility in frontal plane and a more symmetrical redistribution of the frontal trunk sway around the vertical axis during gait. These results suggest the importance of a postural reeducation program for transfemoral amputees aimed at improving pelvic dynamic control while repositioning the trunk by postural corrections during gait.

Functional organisation of the endomembrane network in the digestive gland of the Venus flytrap: revisiting an old story with a new microscopy toolbox.

Up-to-date imaging approaches were used to address the spatiotemporal organisation of the endomembrane system in secretory cells of Dionaea muscipula. Different 'slice and view' methodologies were performed on resin-embedded samples to finally achieve a 3D reconstruction of the cell architecture, using ultrastructural tomography, array tomography, serial block face-scanning electron microscopy (SBF-SEM), correlation, and volume rendering at the light microscopy level. Observations of cryo-fixed samples by high-pressure freezing revealed changes of the endomembrane system that occur after trap activation and prey digestion. They provide evidence for an original strategy that adapts the secretory machinery to a specific and unique case of stimulated exocytosis in plant cells. A first secretion peak is part of a rapid response to deliver digestive fluids to the cell surface, which delivers the needed stock of digestive materials 'on site'. The second peak of activity could then be associated with the reconstruction of the Golgi apparatus (GA), endoplasmic reticulum (ER) and vacuolar machinery, in order to prepare for a subsequent round of prey capture. Tubular continuum between ER and Golgi stacks observed on ZIO-impregnated tissues may correspond to an efficient transfer mechanism for lipids and/or proteins, especially for use in rapidly resetting the molecular GA machinery. The occurrence of one vacuolar continuum may permit continuous adjustment of cell homeostasy. The subcellular features of the secretory cells of Dionaea muscipula outline key innovations in the organisation of plant cell compartmentalisation that are used to cope with specific cell needs such as the full use of the GA as a protein factory, and the ability to create protein reservoirs in the periplasmic space. Shape-derived forces of the pleiomorphic vacuole may act as signals to accompany the sorting and entering flows of the cell.

Initiation of forward gait with lateral occurrence of emotional stimuli: general findings and relevance for pedestrians crossing roads.

With reference to theoretical models regarding links between emotions and actions, the present study examined whether the lateral occurrence of an emotional stimulus influences spatial and temporal parameters of gait initiation in 18 younger and 18 older healthy adults. In order to simulate road-crossing hazard for pedestrians, slides of approaching cars were used and they were presented in counterbalanced order with threatening slides from the International Affective Picture System (IAPS) and control slides of safe walking areas. Each slide was presented on the left side of the participant once the first step was initiated. The results evidenced medio-lateral shifts to the left for the first step (right foot) and to the right for the second step (left foot). These shifts were both modulated by the slide contents in such a way that the resulting distance between the screen and the foot (right or left) was larger with the IAPS and traffic slides than with the control slides. The slides did not affect the base of support, step length, step velocity and time of double support. Advancing age influenced the subjective impact of the slides and gait characteristics, but did not modulate medio-lateral shifts. The data extend evidence of fast, emotional modulation of stepping, with theoretical and applied consequences.

Oleate Abrogates Palmitate-Induced Lipotoxicity and Proinflammatory Response in Human Bone Marrow-Derived Mesenchymal Stem Cells and Osteoblastic Cells.

Osteoporosis is a metabolic bone disease associated with unequilibrated bone remodeling resulting from decreased bone formation and/or increased bone resorption, leading to progressive bone loss. In osteoporotic patients, low bone mass is associated with an increase of bone marrow fat resulting from accumulation of adipocytes within the bone marrow. Marrow adipocytes are active secretory cells, releasing cytokines, adipokines and free fatty acids (FA) that influence the bone marrow microenvironment and alter the biology of neighboring cells. Therefore, we examined the effect of palmitate (Palm) and oleate (Ole), 2 highly prevalent FA in human organism and diet, on the function and survival of human mesenchymal stem cells (MSC) and MSC-derived osteoblastic cells. The saturated FA Palm exerted a cytotoxic action via initiation of endoplasmic reticulum stress and activation of the nuclear factor κB (NF-κB) and ERK pathways. In addition, Palm induced a proinflammatory response, as determined by the up-regulation of Toll-like receptor 4 expression as well as the increase of IL-6 and IL-8 expression and secretion. Moreover, we showed that MSC-derived osteoblastic cells were more sensitive to lipotoxicity than undifferentiated MSC. The monounsaturated FA Ole fully neutralized Palm-induced lipotoxicity by impairing activation of the pathways triggered by the saturated FA. Moreover, Ole promoted Palm detoxification by fostering its esterification into triglycerides and storage in lipid droplets. Altogether, our data showed that physiological concentrations of Palm and Ole differently modulated cell death and function in bone cells. We therefore propose that FA could influence skeletal health.

Enhanced precision of ankle torque measure with an open-unit dynamometer mounted with a 3D force-torque sensor.

PURPOSE: Many studies have focused on maximum torque exerted by ankle joint muscles during plantar flexion. While strength parameters are typically measured with isokinetic or isolated ankle dynamometers, these devices often present substantial limitations for the measurement of torque because they account for force in only 1 dimension (1D), and the device often constrains the body in a position that augments torque through counter movements. The purposes of this study were to determine the contribution of body position to ankle plantar-flexion torque and to assess the use of 1D and 3D torque sensors. METHODS: A custom designed 'Booted, Open-Unit, Three dimension, Transportable, Ergometer' (B.O.T.T.E.) was used to quantify plantar flexion in two conditions: (1) when the participant was restrained within the unit (locked-unit) and (2) when the participant's position was independent of the ankle dynamometer (open-unit). Ten young males performed maximal voluntary isometric plantar-flexion contractions using the B.O.T.T.E. in open and locked-unit mechanical configurations. RESULTS: The B.O.T.T.E. was reliable with ICC higher than 0.90, and CV lower than 7 %. The plantar-flexion maximal resultant torque was significantly higher in the locked-unit compared with open-unit configuration (P < 0.001; +61 to +157 %) due to the addition of forces from the body being constrained within the testing device. A 1D compared with 3D torque sensor significantly underestimated the proper capacity of plantar-flexion torque production (P < 0.001; -37 to -60 %). CONCLUSIONS: Assessment of plantar-flexion torque should be performed with an open-unit dynamometer mounted with a 3D sensor that is exclusive of accessory muscles but inclusive of all ankle joint movements.

Disruption of the secretion and action of 17,20ß-dihydroxy-4-pregnen-3-one in response to a rise in temperature in the Arctic charr, Salvelinus alpinus. Consequences on oocyte maturation and ovulation.

Plasma levels of 17,20ß-dihydroxy-4-pregnen-3-one (17,20ßP), and the timing of ovulation were investigated in female Arctic charr (Salvelinus alpinus) reared at 5°C and at 10°C during the pre-spawning period. The effects of switching from 5 to 10°C, and from 10 to 5°C were also investigated. 17,20ßP plasma levels were higher at 5°C than at 10°C. A switch from 10 to 5°C stimulated 17,20ßP secretion, whereas a switch from 5 to 10°C had the opposite effect. Ovulation occurred spontaneously in the females kept at 5°C, and in those switched from 10 to 5°C. In contrast, ovulation was inhibited in females reared at 10°C, and in those switched from 5 to 10°C. Oocyte maturation at 5°C and at 10°C in the presence of LH or of 17,20ßP was also investigated in vitro using donor females reared at 5 or 10°C. Both LH and 17,20ßP stimulated oocyte maturation more effectively in oocytes incubated at 5°C than at 10°C. At both incubation temperatures, the rearing temperature of the donor females had a significant impact on their responsiveness to LH stimulation, but had no effect on their responsiveness to 17,20ßP stimulation. In addition to the inhibition of LH secretion, which had already been reported, the results reported here show that in Arctic charr raising the temperature above the physiological range reduces both follicular responsiveness to LH stimulation and the sensitivity of oocytes to 17,20ßP stimulation.

Cystatin C for early detection of renal impairment in diabetes.

OBJECTIVES: Evaluation of glomerular filtration rate is of crucial importance in diabetes. Cystatin C, a cysteine protease inhibitor seems to be an interesting parameter. DESIGN AND METHODS: 67 diabetic patients with normal creatinine are evaluated. Cystatin C is compared to renal markers, by reference to Cr EDTA clearance. RESULTS: Significant correlations are found between cystatin C and creatinine (r=0.54). GFR MDRD (r=-0.47) and GFR Cr EDTA (r=-0.47). The AUC of the receiver operating curves is better for GFR MDRD (0.83) and cystatin C (0.75) than for creatinine (0.63) considering the cut off value of 80 mL/min for GFR EDTA. CONCLUSION: Cystatin C seems to be a more sensitive parameter than creatinine for the detection of an incipient nephropathy in diabetes.

Effect of trunk inclination on lower limb joint and lumbar moments in able men during the stance phase of gait.

BACKGROUND: Though the effect of imposed trunk posture affects walking patterns little is known about the effect of natural orientation of the trunk on gait. The objectives of this study are to test if the lower limb joint and thoraco-lumbar moments are similar in subjects who maintain an average natural forward or backward trunk inclination during gait and verify if the lower limbs are equally affected. METHODS: Twenty-five young men were divided according to their natural backward or forward trunk inclination during level walking. Ankle, knee, hip and thoraco-lumbar moments were calculated by an inverse dynamic approach for the two limbs. A two-way ANOVA was performed on peak lower limb moments. A one-way ANOVA was performed on thoraco-lumbar peak moments. FINDINGS: There was a main effect for both trunk inclinations and lower limb sides but no interaction. For the forward leaners, the duration of hip extension moment was longer (P<0.001) while the hip flexion moment was 1.3 times smaller (P<0.001). Differences between the lower limb sides were noted in all joints but at push-off of the stance phase only. The two thoraco-lumbar extension moments were, respectively, 1.4 times higher for the forward leaners while the two flexion moments were approximately 1.4 times higher for the backward leaners. INTERPRETATIONS: The backward leaners propel themselves with a strong hip flexor activity at push-off while the forward leaners use their hip muscles throughout stance. These results support the idea that trunk inclinations and moment variations are associated with the type of walking patterns.

Genotoxic pressure of vineyard pesticides in fish: field and mesocosm surveys.

The present study deals with the genotoxicity assessment of vineyard pesticides in fish exposed in the field or in mesocosm conditions. Primary DNA damage was quantified as strand breaks using the single cell gel electrophoresis assay (Comet assay) applied to fish erythrocytes. In a first experiment, a significant genotoxic effect was observed following an upstream-downstream gradient in early life stages of brown trout (Salmo trutta fario) exposed in the Morcille River contaminated by a mixture of vineyard pesticides during three consecutive years. The pronounced response in terms of DNA damage reported in the present study could argue for a high sensitivity of fish early life stage and/or a high level of exposure to genotoxic compounds in the Morcille River. This stresses the interest in using trout larvae incubated in sediment bed to assess genotoxic compounds in the field. In a second experiment, adult European topminnow (Phoxinus phoxinus) were exposed in water running through artificial channels to a mixture of diuron and azoxystrobin, two of the main pesticides detected in the Morcille watershed. As compared with the unexposed channel, a 3-5-fold increase in the DNA damage was observed in fish exposed to chronic environmental pesticide concentrations (1-2 microg L(-1) for diuron and 0.5-1 microg L(-1) for axoxystrobin). A single 6h pulse of pesticide (14 microg L(-1) of diuron and 7 microg L(-1) of azoxystrobin) was applied to simulate transiently elevated chemical concentrations in the river following storm conditions. It did not increase genotoxicity. After a 1-month recovery period, DNA damage in exposed fish erythrocytes recovered to unexposed level, suggesting possible involvement of both repair mechanisms and cellular turnover in this transient response. This work highlights that vineyard treatment by pesticides and in particular diuron and azoxystrobin can represent a genotoxic threat to fish from contaminated watershed rivers.

Use of a temperature gradient measuring device in monitoring of diabetic and critically ill patients.

A device realizing the simultaneous measure of the central body temperature (Tc), the superficial one (Ts) and their difference (Dt), was proposed for permanent energetic balance evaluation in humans. A program was elaborated to command the intravenous delivery of insulin by a pump depending on the value and trends of Dt. The use of this device for monitoring of decompensated diabetic patients allowed their easier stabilization. In critically ill patients (post transplantation, myocardium infarction) it had a diagnostic and prognostic value, and was helpful for optimization of conventional and insulin therapy.

Financial costs of alcoholism treatment programs: a longitudinal and comparative evaluation among four specialized centers.

BACKGROUND: Alcoholism is a worldwide problem. Many strategies for alcohol detoxification and relapse prevention exist, but each alcohol treatment center has its own program. The objective of this study was to analyze and compare the financial cost and effectiveness of alcohol treatment programs from inpatient stay to follow-up 1 year later. This was a prospective, open, nonrandomized study of 4 specialized alcohol treatment centers and 267 patients admitted for alcohol detoxification. METHODS: We recorded all medical and nonmedical interventions related to the program during patient stay in the hospital and every 3 months after discharge for 1 year and recorded the occurrence of alcohol relapse. Financial evaluation was based on the prices of refund from the French national health insurance service. RESULTS: The mean cost of hospitalization ranged from 1326 euros to 1917 euros(p = 0.001), a variation mainly due to the difference in the length of hospital stay but also to the cost of the inpatient program, routine medical checkups, and drugs administered. The mean cost of 1 year of follow-up per patient ranged from 419 euros to 1704 euros (p = 0.001). The efficiency, corresponding to the money spent to prevent the relapse of one patient during 1 month, was approximately 500 euros/month in three centers and 658 euros in the fourth. However, for a similar efficiency, the effectiveness, assessed by the mean time without relapse, was significantly (p = 0.001) different; center 1, which had the highest total cost, had an effectiveness 1.56 times higher than center 3, which had the lowest cost. CONCLUSIONS: This work emphasizes the heterogeneity of the costs and effectiveness of alcoholism treatment programs and suggests that research should be conducted to determine which program is the most rational, cost-efficient, and beneficial for patients and the public health office economy.

Zebra mussels (Dreissena polymorpha) as indicators of freshwater contamination with lindane.

Zebra mussels are common freshwater mollusks in many European lakes and rivers. Their abundance, wide distribution, and filtering activity make them good candidates to evaluate the contamination of freshwaters with environmental contaminants. The purpose of this work was to determine the kinetics of lindane in zebra mussels and compare laboratory results with in situ measurements. Exposure was conducted in small tanks, under controlled experimental conditions. Our results indicated that mussels accumulated lindane with a bioconcentration factor around 10. They generally reached equilibrium within 4 days. Elimination was rapid but biphasic and the terminal elimination half-life was long (> 168 h). Age of the mussels and temperature also affected the kinetics of lindane in mussels. In the Lake of Geneva, zebra mussels were sampled and showed that mussels accumulated it to significant values (up to 900 ng/g fresh weight) depending on the site and period of sampling. The in situ results, together with the laboratory exposures, showed that freshwater mussels could be used to monitor point sources of pollutants such as lindane over short periods of time (< 1 week).

Decrease in ovalbumin-induced pulmonary allergic response by benzaldehyde but not acetaldehyde exposure in a Guinea pig model.

The pulmonary effects of two environmentally relevant aldehydes were investigated in nonsensitized or ovalbumin (OA)-sensitized guineapigs (GPs). Four-week-old male Hartley GPs, weighing about 400 g, were intraperitoneally injected with 1 ml of an NaCl solution containing 100 microg OA and 100 mg Al(OH)(3). They were then exposed to either acetaldehyde (200 ppb) or benzaldehyde (500 ppb) for 4 wk (6 h/d, 5 d/wk). At the end of exposure, GPs were challenged with an OA aerosol (0.1% in NaCl) and pulmonary functions were measured. The day after, guinea pigs were anesthetized and several endpoints related to inflammatory and allergic responses were assessed in blood, whole-lung histology, and bronchoalveolar lavage (BAL). Sensitized nonexposed GPs showed bronchial hyperresponsiveness to OA and an increased number of eosinophils in blood and BAL, together with a rise in total protein and leukotrienes (LTB(4) and LTC(4)/D(4)/E(4)) in BAL. In nonsensitized GPs, exposure to acetaldehyde or benzaldehyde did not induce any change in the tested parameters, with the exception of irritation of the respiratory tract as detected by histology and an increased number of alveolar macrophages in animals exposed to acetaldehyde. In sensitized GPs, exposure to acetaldehyde induced a moderate irritation of the respiratory tract but no change in biological parameters linked to the inflammatory and allergic responses. In contrast, exposure to benzaldehyde induced a decrease both in OA-induced bronchoconstriction and in eosinophil and neutrophil numbers in BAL, an increase in the bronchodilatator mediator prostaglandin E(2) (PGE(2)), and a decrease in the bronchoconstrictor mediators LTC(4)/D(4)/E(4). Further investigations are needed to determine if the attenuated response observed in sensitized GPs exposed to benzaldehyde is due to an alteration of the mechanism of sensitization or to a more direct effect on various mechanisms of the allergic response.

[Acting out and psychoactive substances: alcohol, drugs, illicit substances]. / Passage à l'acte et substances psychoactives: alcool, médicaments, drogues.

In humans, some psychotropic agents (alcohol, drugs, illicit substances) have been suggested to play a role in the occurrence of major behavioural disorders, mainly due to the suppression of psychomotor inhibition. Behavioural disinhibition is a physiological mechanism which allows humans to behave appropriately according to a given environmental situation. The behavioural disinhibition induced by either therapeutic dosage or misuse involves the loss of restraint over certain types of social behaviour and may increase the risk of auto or hetero-aggression and acting out. The increased use of psychotropic agents in recent years and the occurrence of unwanted effects are worrying and must be detected and evaluated. The objective of the present study was to establish a causal relationship between psychoactive substance use and occurrence of major behavioural disorders, such as paradoxical rage reactions and suicidal behaviour, based on a literature analysis. It consisted of reviewing reports of drug-induced violent reactions in healthy volunteers and demonstrating, where possible, a cause-effect relationship. Patients with schizophrenia and psychopathic personalities were not included in our study since psychiatric comorbidity could influence behavioural responses. Psychotropic agents included drugs, licit and illicit substances already associated with violence in the past. Many reports used the "Go/No Go test" to evaluate the disinhibiting effect of psychotropic substances; this allows the "cognitive mapping" of drugs. The results suggest that only alcohol, antidepressants, benzodiazepines and cocaïne are related to aggressive behaviour. The best known precipitant of behavioural disinhibition is alcohol, which induces aggressive behaviour. However, there are large differences between individuals, and attentional mechanisms are now recognised as being important in mediating the effects of alcohol. Suicidal tendency as an adverse antidepressant reaction is rare, especially with atypical antidepressants. However, the risk of acting out exists and the responsibility of antidepressant agents in the genesis of suicidal tendencies is now established. The disinhibiting effects of benzodiazepines are well-known and proven by clinical trials. It's a "model" of acting out, and the causal relationship is undeniable. That cocaïne is related to violent behaviour is demonstrated by its pharmacological actions on CNS. The chronic use of cocaïne induces "a limbic dyscontrol syndrome" based on the altered activity of limbic structures. On the contrary, we could not demonstrate a causal relationship between aggression and either cannabis, ecstasy or phencyclidine. Cannabis abusers look particularly for euphoria and relaxing effects. Aggression as an adverse cannabis reaction is very rare and occurs in most cases in association with other drugs and in predisposed individuals. Ecstasy use may lead to long-term alterations of neuronal function in the human CNS and cause psychiatric disorders. However, there is insufficient information about long-term use of ecstasy to estimate its role in the occurrence of behavioural disorders. Clinical and forensic assumptions about phencyclidine and violence were not warranted. However, the substance-effect relationships can be criticized in the case of alcohol, antidepressants, benzodiazepines and cocaïne. In fact, individual, social and psychiatric factors exert an influence on behaviour that is superior to the pharmacological effect of psychotropic agents. The most important parameter in drug-induced behavioural disinhibition is dosage, but mode of administration is also important. In addition, polysubstance abuse is very common. Substances may be taken simultaneously and alcohol is frequently combined with drugs. The combinations of substances result in multiple interactions, and very little is known about the effects of these interactions on violence in humans. Co-occurrence of substance abuse and other mental disorders is also very frequent. Multiple substance abuse should be avoided, because potential interactions between two or more drugs are more likely to cause violent behaviour. In the future, a specific treatment of these deleterious phenomena will have to be considered in order to reduce drug-induced iatrogenic behavioural disorders.