Biomechanics of Exoskeleton-Assisted Treadmill Walking.

To exploit the benefits of treadmill-based exoskeletons, it is crucial to assess possible deviations from natural walking depending on assistive parameters. This study evaluated the biomechanics of exoskeleton-assisted treadmill walking by comparing it with free gait. Five healthy participants walked freely on a treadmill and with the assistance of the Lokomat gait trainer, while changing Body Weight Support (BWS), Gait Speed (GS), and Guidance Force (GF). Results showed that the hip and knee joint kinematics depended on BWS and GS, while changes due to GF were limited. Moreover, joint kinematics and the activity of related muscles were altered with respect to free gait, for any combination of robot parameters in the case of the ankle, and especially for low GS and with BWS in the case of hip and knee. Overall, walking with the Lokomat can mostly resemble free gait at high speed and without BWS.

An ISB-consistent Denavit-Hartenberg model of the human upper limb for joint kinematics optimization: validation on synthetic and robot data during a typical rehabilitation gesture.

Several biomedical contexts such as diagnosis, rehabilitation, and ergonomics require an accurate estimate of human upper limbs kinematics. Wearable inertial measurement units (IMU s) represent a suitable solution because of their unobtrusiveness, portability, and low-cost. However, the time-integration of the gyroscope angular velocity leads to an unbounded orientation drift affecting both angular and linear displacements over long observation interval. In this work, a Denavit-Hartenberg model of the upper limb was defined in accordance with the guidelines of the International Society of Biomechanics and exploited to design an optimization kinematics process. This procedure estimated the joint angles by minimizing the difference between the modelled and IMU-driven orientation of upper arm and forearm. In addition, reasonable constraints were added to limit the drift influence on the final joint kinematics accuracy. The validity of the procedure was tested on synthetic and experimental data acquired with a robotic arm over 20 minutes. Average rms errors amounted to 2.8 deg and 1.1 for synthetic and robot data, respectively. Clinical Relevance - The proposed method has the potential to improve robustness and accuracy of multi-joint kinematics estimation in the general contexts of home-based tele-rehabilitation interventions. In this respect adoption of multi-segmental kinematic model along with physiological joint constraints could contribute to address current limitations associated to unsupervised analysis in terms of monitoring and outcome assessment.

Post-operative analgesia following TPLO surgery: A comparison between cimicoxib and tramadol.

OBJECTIVE: To compare the analgesic effects of oral administration of cimicoxib and tramadol over a 30 day period following Tibial Plateau Leveling Osteotomy and partial menisectomy in dogs. DESIGN: Randomized, double blinded, prospective clinical trial. ANIMALS: 42 adult client-owned dogs with unilateral cranial cruciate ligament disease and partial meniscal tears. METHODS: Dogs were allocated into 2 treatment groups (cimicoxib or tramadol). Weight bearing while standing, thigh circumference, flexion and extension range of motions, wound classification, adverse effects, Visual Analogue Scale (VAS), Glasgow Composite Measure Pain Scale (CMPS-SF) and Helsinki Chronic Pain Index (HCPI) questionnaire and limb function by means of pressure platform gait analysis were recorded before surgery and at several time points after surgery for 30 days. Outcome measures were compared at each time point among groups. RESULTS: A significant improvement in two objective measures of gait of the cimicoxib group: the vertical impulse on day 1 and day 20 and the peak vertical force on day 20 were significantly improved when compared to the tramadol group. However, no difference was seen for the VI or PVF of dogs on the other days compared. In addiction there was no difference in the weight bearing while standing, thigh circumference, wound classification, adverse effects, VAS, CMPS-SF and HCPI. We did not observe a difference in the number of adverse effects measured in this study with the exception of hock edaema. CONCLUSIONS AND CLINICAL RELEVANCE: A significant difference was not found in long-term postoperative analgesia provided by cimicoxib or tramadol in dogs undergoing TPLO when subjective parameters (with the exception of knee joint range of motion) were evaluated, but use of the force plate analysis revealed a significant difference between groups at T20 for both PVF and VI. The use of cimicoxib improved the limb function and ROM and reduced the occurrence of hock edema, in the first 20 days after surgery, without any additional side effects, compared to tramadol. Thus, the use of cimicoxib should be preferred to tramadol alone in clinical cases similar to the ones included in this study.

Two-Segment Foot Model for the Biomechanical Analysis of Squat.

Squat exercise is acquiring interest in many fields, due to its benefits in improving health and its biomechanical similarities to a wide range of sport motions and the recruitment of many body segments in a single maneuver. Several researches had examined considerable biomechanical aspects of lower limbs during squat, but not without limitations. The main goal of this study focuses on the analysis of the foot contribution during a partial body weight squat, using a two-segment foot model that considers separately the forefoot and the hindfoot. The forefoot and hindfoot are articulated by the midtarsal joint. Five subjects performed a series of three trials, and results were averaged. Joint kinematics and dynamics were obtained using motion capture system, two force plates closed together, and inverse dynamics techniques. The midtarsal joint reached a dorsiflexion peak of 4°. Different strategies between subjects revealed 4° supination and 2.5° pronation of the forefoot. Vertical GRF showed 20% of body weight concentrated on the forefoot and 30% on the hindfoot. The percentages varied during motion, with a peak of 40% on the hindfoot and correspondently 10% on the forefoot, while the traditional model depicted the unique constant 50% value. Ankle peak of plantarflexion moment, power absorption, and power generation was consistent with values estimated by the one-segment model, without statistical significance.

Biomechanics of simulated versus natural cross-country sit skiing.

The purpose of this study was to investigate the biomechanics of cross-country sit-skiing in simulated and natural skiing. Thirteen international level athletes participated in a ski ergometer test (simulated conditions) and a test on snow in a ski-tunnel (natural conditions) using their personal sit-ski. Tests in both conditions were performed at individual maximal speed. When comparing the two conditions the main results were: (1) maximal speed in simulated conditions was lower (p<0.05) but correlated well with the natural condition (r=0.79, p<0.001); (2) no differences in pole force variables were found; peak force (r=0.77, p<0.01) and average force (r=0.78, p<0.01) correlated well; (3) recovery time and time to peak did not differ and time to impact correlated with each other (r=0.88, p<0.01); (4) no differences were found in peak electromyography (EMG) and average EMG for Triceps, Pectoralis, and Erector Spinae; Rectus Abdominis did not differ in peak. EMG peak and average EMG of all muscles were correlated between the two conditions (r=0.65-0.94; p<0.05-0.01). Although some differences were observed, this study demonstrated that technical skill proficiency in natural and simulated cross-country skiing is comparable from a force production and muscle activation perspective.

Effects of botulinum neurotoxin on spatio-temporal gait parameters of patients with chronic stroke: a prospective open-label study.

BACKGROUND: Nowadays, administration of botulinum neurotoxin type A is considered a safe, well tolerated and effective treatment for muscles tone reduction in focal spasticity care. Lack of evidence regards instead its functional role on gait parameters, as well patterns. AIM: To assess the botulinum neurotoxin treatment efficacy on chronic poststroke subjects, in order to investigate its functional effects on spatio-temporal gait parameters, in addition to the evaluation of spasticity grade based on clinical scales. DESIGN: A prospective open-label study along 16-weeks trials. SETTING: Outpatient neurophysiology rehabilitation structure and laboratory of movement and gait analysis. POPULATION: Twenty chronic poststroke patients, suffering from equinovarus foot deformity, with a stabilized hemiparesis were recruited according to inclusion criteria of the protocol. METHODS: Single neurotoxin-based local intramuscular injections were given according to a specific protocol concerning both the considered muscles and the relative toxin doses, with a maximum total dose ranged between 200 U and 400 U. Patients were observed both at baseline (t0) and for 4 following monthly visits (t1, t2, t3, t4) after injections at baseline. Gait analysis sessions were performed at each visit, by means of a video-cameras based system and body reflective markers attached to the body, based on a protocol. Authors focus on both global and local gait temporospatial parameters, such as walking speed, stride-length, cadence, stride-time, step-width, single limb support, double support and limp index to point out the functional changes due to the treatment. For comparison prior to and after the treatment, clinical scales like Modified Ashworth Scale, Berg Balance Scale and Rivermead Mobility Index have been also considered. RESULTS: Subsequent to the neurotoxin intramuscular injections, patients reported statistical significant gait improvements after 90 days (t3) regarding temporospatial parameters: (P<0.05) for walking speed, single limb support and double support and (P<0.10) for stride-length, stride-time, cadence and step-width. CONCLUSION: The botulinum neurotoxin treatment has demonstrated its efficacy for a functional recovery of gait, as pointed out by a statistically significant improvement of some spatio-temporal parameters. Thus, the analyzed changes reveal an improved balance and self-confidence in gait. Studies involving a wider population data are nevertheless needed to better confirm this efficacy. CLINICAL REHABILITATION IMPACT: The poststroke botulinum neurotoxin-based treatment is a safe and potentially useful neurorehabilitative approach for the analyzed data.

Mesoporous silica as a carrier for topical application: the Trolox case study.

As part of a recent research effort aimed at employing mesoporous materials for controlled drug delivery, this paper presents MCM-41 as a carrier for topical application, using Trolox as a model unstable guest molecule. The complexes between Trolox and MCM-41 were prepared by employing different inclusion procedures, varying solvent, method and pretreatment of the silica matrix. The objectives of this study were to determine Trolox loading, analyze its integrity and availability after immobilization on mesoporous silica, evaluate MCM-41 influence on Trolox photodegradation and establish whether the preparation method significantly influences complex properties. The characterization analyses (XRD, TGA, DSC and FTIR) confirmed the hydrogen-bonding interaction and Trolox structure preservation. Gas-volumetric analysis showed a consistent decrease in surface area and in pore volume and diameter with respect to bare MCM-41 indicating that Trolox was mainly located within mesopores. In vitro diffusion tests showed a slower release of Trolox after inclusion in the MCM-41 matrix; at the same time UV irradiation studies highlighted an increased photostability for the complex particularly in O/W emulsion. Moreover the radical scavenging activity of Trolox was maintained after immobilization. In all cases, differences were observed in all tested samples, suggesting that results could be optimized by modifying the inclusion procedure and by improving the guest loading.

Can Hediste diversicolor (Nereidae, Polychaete) be considered a good candidate in evaluating PAH contamination? A multimarker approach.

The aim of this study was to develop a preliminary characterization of the biological responses of Hediste diversicolor to polycyclic aromatic hydrocarbons (PAHs) under controlled laboratory conditions. In order to test the effects of PAH exposure, a battery of biomarkers was applied to the polychaetes by exposing them to sublethal concentrations of benzo[a]pyrene (0.1 and 0.5 mg L(-1)) for 10d under laboratory conditions. The battery of biomarkers tested included oxidative stress biomarkers (glutathione content, enzymatic activities of catalase, glutathione S-transferases, glutathione reductase, glutathione peroxidases), total oxyradical scavenging capacity (TOSC) toward peroxyl and hydroxyl radicals and activity of acyl CoA oxidase (AOX) as a marker of peroxisome proliferation measured in the entire body; lipofuscin and neutral lipid accumulations and levels of Ca(2+)-ATPase activity analyzed in the intestinal epithelium; lysosomal membrane stability and genotoxic effects measured as DNA strand breaks and frequency of micronuclei in coelomocytes. Chemical analyses were also carried out to verify the polychaete's benzo[a]pyrene (B[a]P) bioaccumulation levels after the exposure period. The results obtained indicate that B[a]P caused significant changes in most of the parameters measured in H. diversicolor. Biological responses to the organic compound were particularly significant for the biomarkers measured in the intestinal epithelium and in coelomocytes, emphasizing that these tissues were more affected during our experimental conditions. Considering the key trophic role of this benthic species in estuarine and coastal ecosystems, this study confirmed that H. diversicolor is an appropriate bioindicator of organic contamination.

Histopathology alterations and histochemistry measurements in mussel, Mytilus edulis collected offshore from an aluminium smelter industry (Norway).

Histopathological characteristics of specific organs express condition, and represent time-integrated impacts on the organism stemming from alterations at lower levels of biological organisation. As integrative parameters, histochemical investigations have proved to be sensitive tools to detect effects of chemical compounds. The objective of this study was to determine changes in the tissues of mussels collected at a PAH contaminated site compared to a reference site using histopathological and histochemical parameters: lipofuscin (LF) accumulation in mussel digestive gland, and lysosomal membrane stability (LMS), and using additional information provided by body burden analysis to compare the sensitivity of these parameters. The histochemical measurements for both LF and LMS gave a clear indication of a high level of stress in animals from the PAH contaminated site. This LF accumulation in lysosomes is the result of peroxidation of autophagocytosed proteins associated with protein aggregates and oxidatively damaged organelles. These measurements were able to detect the effects of PAHs, and showed a strong relationship with the body burden results.

Inguino-scrotal hernia of a double district ureter: case report and literature review.

Ureteral hernia is uncommon and usually misdiagnosed. From an anatomic point of view, we can distinguish between two uretero-inguinal hernias: intraperitoneal and extraperitoneal. Ureter inguinal hernias are nearly always indirect. This kind of hernia can include the ureter alone or, frequently, other abdominal sliding organs within the hernia sac (bladder, bowel tracts, etc.). Kidneys and urinary tracts present normal anatomic conformation, although renal ptosis may be found. As of July 2004, 139 cases of ureteral hernia had been described in the literature. Here we report a case of inguino-scrotal herniation of double district ureter and review the current literature to analyze the main clinical characteristics of this pathology and to establish pitfalls.

Heart rate variability and left ventricular diastolic function in patients with borderline hypertension with and without left ventricular hypertrophy.

The relationships between heart rate variability (HRV), left ventricular mass and diastolic function in borderline hypertensive patients (BHT) were evaluated. 24 h Holter electrocardiogram (ECG) and blood pressure (BP) monitoring, M and 2 D echocardiogram and Doppler analysis in 42 BHT with and without left ventricular hypertrophy (LVH) and in 20 normotensive controls were assessed. From 24-h ECG, time domain indexes of HRV were calculated. Standard Deviation of all Cycles (SDNN) and Standard Deviation of the means of heart periods over five-minute intervals (SDANN) were significantly reduced in BHT with LVH but not in BHT without LVH. No significant differences of short-term variability measures were detectable, although a progressive decrease among control subjects and BHT with and without LVH was observed. Diastolic left ventricular compliance evaluated by early to late transmitral flow velocity ratio (E/A ratio) significantly declined from normotensive subjects to BHT with LVH. There was a significant positive correlation between E/A and SDNN and SDANN throughout all studied groups. This indicates that BHT with LVH has a reduced HRV compared to other groups. This impairment is probably related to left ventricular mass and left ventricular filling abnormalities.

Twelve-year follow up with the Sorin Pericarbon bioprosthesis in the mitral position.

BACKGROUND AND AIMS OF THE STUDY: The aim of this study was to evaluate the long-term follow up of the Pericarbon pericardial bioprosthesis implanted in the mitral position. METHODS: Between January 1985 and January 1991, 78 patients (26 males, 52 females; mean age 56.9 +/- 7.8 years) underwent isolated mitral valve replacement with a Pericarbon valve. All bioprostheses were size 29 mm and implanted by the same surgeon. RESULTS: Total follow up was 663.2 pt-years and it was 97% complete. Early mortality was 1.3% (1/78); two minor cerebral embolisms were observed as early complications. At 12 years the overall survival rate was 85.0 +/- and valve-related survival 93.1 +/- 3.0%; freedom from embolic events was 83.0 +/- 4.5% and from endocarditis 98.7 +/- 1.3%. Freedom from primary tissue failure was 56.8 +/- 6.6%; it was 86.3 +/- 7.5% in patients aged > 60 years and 36.8 +/- 8.2% in younger patients. There were 27 reoperations, 26 for primary tissue failure, one for endocarditis. Comparison between basal and follow up echocardiographic studies showed a significant stenotic deterioration of the bioprosthesis and a negligible incidence of regurgitation. Morphological findings of explanted bioprostheses were characterized by stenotic and diffuse microcalcification, but no tissue tear was observed. CONCLUSIONS: These results confirm that the Pericarbon bioprosthesis is structurally safe and free from the fatigue problems which afflicted the first and second generation of pericardial valves. As with other tissue valves, the rate of calcification is age-dependent, suggesting preferential use of the Pericarbon prosthesis in elderly people.

Differential Response in Left Ventricular Mass and Arterial Resistive Index following Fosinopril Therapy.

The aim of this study was to assess the differential response in left ventricular mass and resistive index (RI) of renal and carotid arteries in mild to moderate essential hypertensive patients after 1 year of ACE inhibitor therapy. Twenty-six patients (mean age 42.9 +/- 10.9 years) underwent 24-hour ambulatory blood pressure monitoring, echocardiography and renal and carotid echo-Doppler (by measuring RI, as an expression of arterial impedance) after a placebo period and 12 months of fosinopril treatment (20 mg/day). Our study showed a significant decrease in 24-hour BP (p < 0.05), left cardiac mass (p < 0.05) and RI of common carotid and hilum renal arteries (p < 0.05). In contrast, there were no significant reductions in the interlobar renal RI (as an expression of unchanged intrarenal resistance) and in the internal carotid artery RI. While the 24-hour BP decrease was strongly correlated with the left cardiac mass modifications (r = 0.73, p < 0.005), no significant relationship was observed with the renal and carotid artery parameters. In conclusion, the present study demonstrated that long-term treatment with fosinopril produced a differential response in left ventricular mass and arterial RI in patients with mild to moderate essential hypertension. In addition, the arterial impedance modifications of common carotid and hilum renal artery were largely unrelated to the 24-hour BP reduction.

[Use of Valtrac in digestive surgery. Initial clinical experience]. / L'uso del Valtrac in chirurgia digestiva. Iniziale esperienza clinica.

Stapling instruments are being currently used for digestive or colorectal anastomoses with definite advantages. The authors report their initial clinical experience about BAR utilization to restore intestinal continuity after upper digestive and colorectal resections. The authors have been carried out 20 anastomoses on 18 patients: 11 males and 7 females. Eleven (61.1%) of them were affected with malignant neoplasms and in 9 cases were performed an urgency procedure. The colorectal and jejunal-jejunal anastomoses were performed, respectively, in 8 cases; gastric-jejunal and ileo-colic anastomoses, respectively, in 2. The satisfactory results obtained seem to demonstrate that the biofragmentable anastomotic ring constitutes a "safe" method of bowel junction of the whole digestive apparatus.

Interleukin-1 receptors and receptor antagonist in haemodialysis.

BACKGROUND: Biological activity of interleukin-1 (IL-1) depends on the number and type of IL-1 receptors on target cells and on the amounts of its naturally occurring inhibitor, the IL-1 receptor antagonist (IL-1ra). METHODS: Expression of IL-1 receptor was studied on the peripheral blood mononuclear cells of 20 end-stage renal-disease patients maintained by chronic haemodialysis by means of either polysulphone (10 patients) or cuprophane membranes (10 patients) and compared to that of normal controls. Plasma and cellular levels of IL-1ra and IL-1 beta were also measured. RESULTS: The proportion of monocytes expressing the IL-1 receptor was strikingly higher in haemodialysis patients than in the healthy population. This proportion further increased during haemodialysis with cuprophane but not with polysulphone. Expression of the IL-1 receptor on lymphocytes was very low in both controls and dialysed patients; in the latter there was no intradialytic variation. Plasma concentrations of IL-1 beta and IL-1ra were elevated in haemodialysis patients and undetectable in controls. Whereas plasma IL-1 beta decreased throughout haemodialysis, IL-1ra further increased, with no significant differences between the two membranes used. Total cellular IL-1 beta and IL-1ra were also higher in the patient group than in the healthy controls. A further increase of both IL-1 beta and IL-1ra was detected at the end of the haemodialysis session with any membrane. CONCLUSIONS: Monocytes of haemodialysis patients circulate in a state of activation, which makes them both producer and target of IL-1. Thus there is an autocrine upregulation of IL-1 production. Although IL-1ra levels are high, they are most likely to be expression of monocyte activation rather than represent effective inhibitors of IL-1 activity.

[Computerized archives in surgery. Our experience]. / Archiviazione computerizzata in chirurgia. Nostra esperienza.

In recent years, the necessity for a surgical department to obtain a wide range of clinical data in a short period is greatly increased. This necessity has been almost satisfied with widespread use of information systems in medicine using database programs and the integration of these database with other programs has allowed graphic representation of data. Anyhow, some difficulties are still present, such as low knowledge in using personal computers and lacking of a common program for all surgical departments. In the article the authors present a computerized program for the filing of medical records in a surgical department. Starting from January 1992, clinical data of all patients admitted in our department have been recorded in the described program. After three years of use, the system has shown to be easy to use, and able to give useful information for data analysis regarding the population observed, the clinical activity performed and the level of quality obtained. For these reasons, it can represent an attempt to diffuse and uniform computerized data recording in surgical departments.

[Emergency abdominal surgery in the aged]. / L'urgenza addominale chirurgica nell'anziano.

The results of 93 elderly patients, subdivided in two age groups (> 65 < 80 years; > 80 years), undergoing abdominal surgery in immediate or delayed emergency over the past five years are reported. The overall morbility was 47.3% (48 complications in 44 patients); among the complications, sepsis was the first factor in frequency in either group (group I: 28.1%, group II: 17.2%), and was reported mostly in patients with associated diseases (group I: 61.1%, group II: 60%). Overall mortality was 16.2% (group I: 15.6%, group II: 17.2) related to 15 patients; among them, 10 had associated diseases (66.6%). The authors try to identify risk factors and their influence in prognosis and propose a multidisciplinary approach in the pre and postoperative period.

[The importance of using computed tomographic scanning in breast irradiation after conservative treatment]. / L'importanza dell'utilizzazione delle scansioni con Tomografia Computerizzata nell'irradiazione della mammella dopo trattamento conservativo.

Conservative surgery followed by radiotherapy is the current treatment of choice for primary breast cancer: indeed, this protocol ensures local control, relatively good cosmetic results and NED survival values similar to those of more invasive surgery. Radiotherapy requires the optimization of the irradiation technique to minimize the dose to the organs at risk. To this purpose, 30 patients submitted to quadrantectomy for breast carcinoma and then to radiotherapy on the residual breast were examined, January through December, 1994, at the Radiotherapy Service of the Ivrea Hospital, to investigate if CT can help optimize treatment planning, sparing as much of the pulmonary tissue underlying the residual breast as possible. Our series of patients was then compared with a literature series whose treatment had been planned only on the mapping of body outline. Some interesting considerations follow from our results: 1) With CT, larger fields can be used than those used with the body outline, so that the planned target volume can be more closely approached; 2) Larger fields can be used because the critical organ included in the irradiation field is more correctly and precisely defined; 3) The comparison with the literature shows that in the past the fields were larger, because the target volume and the critical organ were more difficult to define. The use of larger fields means a higher dose to the lung and thus maybe a higher risk of radiation pneumonia.

[Mitral valve bioprosthesis from bovine pericardium. Color Doppler echographic study and long-term follow up]. / Bioprotesi valvolari mitraliche di pericardio bovino. Studio ecocardiografico e color Doppler e follow-up a lungo termine.

Pericardial heart valve bioprostheses have been utilized for 20 years. In spite of encouraging initial results, long-term follow-up showed a higher incidence of structural failures and primary tissue failures than porcine bioprostheses. Pericarbon represents the newest generation of bovine pericardial bioprostheses. Aim of this study is the long-term evaluation with echocardiographic and color Doppler technique of an innovative bioprostheses, in particular, its morfological and functional characteristics. From 1985 to 1989, 78 consecutive patients (21 males, 57 females, mean age 56.5 +/- 8.16 years) underwent mitral valve replacement with Pericarbon 29, by the same operator, who preserved the mitral posterior leaflet. One month after operation, 21 of these patients underwent echo-color Doppler evaluation, in normalized hemodynamic conditions (normality ranges). In 1995, at the end of the followup, 30 of the remaining 54 patients underwent new echo-color Doppler evaluation and these data were compared with normality ranges values. Leaflets' thickness increased from 0.98 +/- 0.09 to 2.87 +/- 0.73 mm (anterior leaflet; p < 0.0001) and from 1.02 +/- 0.08 to 2.71 +/- 0.45 mm (posterior leaflet; p < 0.0001) 43.3% of anterior leaflet and 53.3% of posterior leaflet showed fibrocalcic lesions. Mean transvalvular gradient increased from 3.4 +/- 0.2 to 6.6 +/- 3.4 mmHg (p < 0.0001); also functional area decreased (p < 0.0001). We have found no paraprosthetic regurgitation and a very low number of central prosthetic regurgitation. Left ventricular function, evaluated by ejection fraction and regional kinesis, remained substantially preserved.