Three dimensional preparatory trunk motion precedes asymmetrical upper limb movement

Three-dimensional trunk motion. trunk muscle electromyography and intra-abdominal pressure were evaluated to investigate the preparatory control of the trunk associated with voluntary unilateral upper limb movement. The directions of angular motion produced by moments reactive to limb movement in each direction were predicted using a three-dimensional model of the body. Preparatory motion of the trunk occurred in three dimensions in the directions opposite to the reactive moments. Electromyographic recordings from the superficial trunk muscles were consistent with preparatory trunk motion. However, activation of transversus abdominis was inconsistent with control of direction-specific moments acting on the trunk. The results provide evidence that anticipatory postural adjustments result in movements and not simple rigidification of the trunk. (C) 2000 Elsevier Science B.V. All rights reserved.

Perturbed upper limb movements cause short-latency postural responses in trunk muscles

Addition of a load to a moving upper limb produces a perturbation of the trunk due to transmission of mechanical forces. This experiment investigated the postural response of the trunk muscles in relation to unexpected limb loading. Subjects performed rapid, bilateral shoulder flexion in response to a stimulus. In one third of trials, an unexpected load was added bilaterally to the upper limbs in the first third of the movement. Trunk muscle electromyography, intra-abdominal pressure and upper limb and trunk motion were measured. A short-latency response of the erector spinae and transversus abdominis muscles occurred similar to 50 ms after the onset of the limb perturbation that resulted from addition of the load early in the movement and was coincident with the onset of the observed perturbation at the trunk. The results provide evidence of initiation of a complex postural response of the trunk muscles that is consistent with mediation by afferent input from a site distant to the lumbar spine, which may include afferents of the upper limb.

Properties of the vertebrate skeletal muscle tubular system as a sealed compartment

Confocal imaging of impermeant fluorescent dyes trapped in the tubular (t-) system of skeletal muscle fibres of rat and cane toad was used to examine changes in the morphology of the t-system upon mechanical skinning, the time course of dye loss from the sealed t-systern in mechanically skinned fibres and the influence of rapid application and removal of glycerol on the morphology of the sealed t-system. In contrast to intact fibres, which have a t-systern open to the outside, the sealed t-systern of toad mechanically skinned fibres consistently displayed local swellings (vesicles). The occurrence of vesicles in the sealed t-system of rat-skinned fibres was infrequent. Application and removal of 200-400 mM glycerol to the sealed t-system did not produce any obvious changes in its morphology. The dyes fluo-3, fura-2 and Oregon green 488 were lost from the sealed t-system of toad fibres at different rates suggesting that the mechanism of organic anion transport across the tubular wall was not by indiscriminate bulk transport. The rate of fluo-3 and fura-2 loss from the sealed t-system of rat fibres was greater in rat than in toad fibres and could be explained by differences in surface area: volume ratio of the t-system in the two fibre types. Based on the results presented here and on other results from this laboratory, an explanation is given for the formation of numerous vesicles in toad-skinned fibres and lack of vesicle formation in rat-skinned fibres. This explanation can also help with better understanding the mechanism responsible for vacuole formation in intact fibres. (C) 2002 Elsevier Science Ltd. All rights reserved.

Equine laminitis: Bites by Bothrops spp cause hoof lamellar pathology in the contralateral as well as in the bitten limb

The envenoming caused by Bothrops snakebite includes local symptoms, such as pronounced edema, hemorrhage, intense pain, vesicles, blisters and myonecrosis. The principal systemic symptom consists in the alteration of blood clotting, due to fibrinogen consumption and platelet abnormalities. The horses involved in this study had this symptomatology and one of them exhibited symptoms consistent with laminitis in the bitten and in the contralateral limbs. Laminitis lesions were characterized by separation of the hoof lamellar basement membrane (BM) from basal cells of the epidermis. These results demonstrated that Bothrops snake venom can induce acute laminitis. We conclude that components of the venom, probably metalloproteinases, cause severe lesions in the hoof early in the envenoming process. Antivenom therapy must be initiated as soon as possible in order to prevent complications, not only to save the life of an envenomed horse, but also to avoid the dysfunctional sequels of laminitis. (c) 2006 Elsevier Ltd. All rights reserved.

Meta-analysis of infrapopliteal angioplasty for chronic critical limb ischemia

Background: Percutaneous transluminal angioplasty has been used with increasing frequency in the treatment of infrainguinal arterial occlusive disease. This meta-analysis aimed to assess the middle-term outcomes after crural angioplasty in patients with chronic critical limb ischemia and compare results with a meta-analysis of popliteal-to-distal vein bypass graft. Methods: Data were retrieved from 30 articles published from 1990 through 2006 (63% of articles published between 2000 and 2006). All studies used survival analysis, reported a 12-month cumulative rate of patency or limb salvage, and included at least 15 infrapopliteal angioplasties. The outcome measures were immediate technical success, primary and secondary patency, limb salvage, and patient survival. Data from life-tables, survival curves, and texts were used. Results. The pooled estimate of success was 89.0% +/- 2.2% for immediate technical result. Results at 1 and 36 months were 77.4% +/- 4.1% and 48.6% +/- 8.0% for primary patency, 83.3% +/- 1.4% and 62.9% +/- 11.0% for secondary patency, 93.4% +/- 2.3% and 82.4% +/- 3.4% for limb salvage, and 98.3% +/- 0.7% and 68.4% +/- 5.5% for patient survival, respectively. Studies with >75% of the limbs with tissue loss fared worse than their respective comparative subgroup for technical success and patency but not for limb salvage or survival. No publication bias was detected. Conclusion: The technical success and subsequent durability of crural angioplasty are limited compared with bypass surgery, but the clinical benefit is acceptable because limb salvage rates are equivalent to bypass surgery. Further studies are necessary to determine the proper role of infrapopliteal angioplasty.

Contraction of the abdominal muscles associated with movement of the lower limb

Background and Purpose. Activity of the trunk muscles is essential for maintaining stability of the lumbar spine because of the unstable structure of that portion of the spine. A model involving evaluation of the response of the lumbar multifidus and abdominal muscles to leg movement was developed to evaluate this function. Subjects. To examine this function in healthy persons, 9 male and 6 female subjects (mean age = 20.6 years, SD = 2.3) with no history of low back pain were studied. Methods. Fine-wire and surface electromyography electrodes were used to record the activity of selected trunk muscles and the prime movers for hip flexion, abduction, and extension during hip movements in each of these directions. Results. Trunk muscle activity occurring prior to activity of the prime mover of the limb was associated with hip movement in each direction. The transversus abdominis (TrA) muscle was invariably the first muscle that was active. Although reaction time for the TrA and oblique abdominal muscles was consistent across movement directions, reaction time for the rectus abdominis and multifidus muscles varied with the direction of limb movement. Conclusion and Discussion. Results suggest that the central nervous st stem deals with stabilization of the spine by contraction of the abdominal and multifidus muscles in anticipation of reactive forces produced by limb movement. The TrA and oblique abdominal muscles appear to contribute to a function not related to the direction of these forces.

Limb Salvage Using Bypass to the Perigeniculate Arteries

Objective: To describe bypass to perigeniculate vessels for limb salvage. Design: Retrospective cohort study. Material and methods: Between 1995 and 2009, 47 bypass procedures to perigeniculate collateral arteries were performed in 46 patients (15 women, 31 men; median age, 68 years). All patients presented with critical ischaemia (tissue loss in 87.5%, rest pain in 12.5%). Mean ankle brachial index was 0.27 +/- 0.17. The site of distal anastomosis was the descending genicular artery (DGA) in 23 bypasses (1 bilateral) and the medial sural artery (MSA) in 24. Proximal anastomosis was to the external iliac artery in 2 cases, common femoral artery in 23 cases, superficial femoral artery in 8 cases, deep femoral artery in 8 cases, above-knee poplitaeal artery in 2 cases, and previous graft in 4 cases. Results: There were four deaths during the immediate postoperative period. Mean follow-up duration was 27 months. Ten patients required major amputation. Mean ankle brachial index post-operatively was 0.60 +/- 0.21. At 3 years, primary patency was 74.7 +/- 7%, secondary patency was 83.4 +/- 8%, and the limb salvage and survival rates were 73.5 +/- 7% and 77.4 +/- 7%, respectively. Conclusion: Bypass to perigeniculate arteries is a viable treatment option for critical limb ischaemia in selected patients. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Effect of IIb-IIIa Glycoprotein Inhibitors in a Partial Limb Amputation Model Submitted to Warm Ischemia in Rats

Viability and functional results of a segment replantation depend on the prevention of deleterious effects of ischemia. Prolonged ischemia leads to alterations in the microcirculation: thrombosis, edema, production of oxygen free radicals, and platelet aggregation. The effect of IIb-IIIa glycoprotein inhibitors was tested in a partial limb amputation model submitted to warm ischemia. The male Wistar rats were divided into four groups: G1 with 0 hours of ischemia and saline (n = 20), G2 with 6 hours of ischemia and saline (n = 24), G3 with 6 hours of ischemia and abciximab (n = 23), and G4 with 6 hours of ischemia and tirofiban (n = 29). The limbs were observed for 7 days and classified as viable or nonviable. Viability, and mortality rates were obtained and analyzed by Q-square and Fisher exact tests (p < 0.05). The viability rates were 100% (G1), 30% (G2), 77.78% (G3), and 80.95% (G4). G2 was statistically different from G1, G3, and G4. G1, G3, and G4 were not statistically different. Transoperative and postoperative mortalities were not statistically different. The administration of abciximab and tirofiban improved limb salvage after ischemia and reperfusion and did not modify mortality rates significantly.

Isolated limb perfusion with melphalan for human melanoma xenografts in the hindlimb of nude rats: A surviving animal model

We have established a surviving model of isolated limb perfusion using xenografts of the human melanoma cell line MM 96L injected subcutaneously into the hindlimb of a nude rat, The femoral artery and vein were cannulated via the left renal artery and vein and the hind limb was isolated using tourniquets. The limb was perfused with Krebs Heinseleit buffer at 37 degrees C containing 4.7% bovine serum albumin at a constant flow rate of 4 mi per min for 30-60 min with 100% survival of the animals, Tumour vascularization and blood flow were demonstrated using vascular casts and [Cr-51]-microspheres. Following the addition of melphalan (15 or 100 mu g/ml), drug concentrations in the perfusate, tissues and systemic circulation were determined using high pressure liquid chromatography (HPLC), Systemic leakage, assessed using [I-125]albumin and melphalan and detected by a gamma-counter and HPLC respectively, was <0.5%. The melphalan concentration and tissue flow rate in the tumour deposits were 40 and 30% respectively, when compared with the surrounding subcutaneous tissue, At a dose of 15 mu g/ml, melphalan caused a reduction in tumour growth after 60 min perfusion, and a significant reduction in tumour size was seen when the melphalan dose was 100 mu g/ml. The surviving nude rat model of isolated limb perfusion for recurrent melanoma will allow examination of optimal perfusion conditions, along with the pharmacokinetics, pharmacodynamics and efficacy of melphalan and other drugs.

Melphalan dosing regimens for management of recurrent melanoma by isolated limb perfusion: Application of a physiological pharmacokinetic model based on melphalan distribution in the isolated perfused rat hindlimb

The optimal dosing schedule for melphalan therapy of recurrent malignant melanoma in isolated limb perfusions has been examined using a physiological pharmacokinetic model with data from isolated rat hindlimb perfusions (IRHP), The study included a comparison of melphalan distribution in IRHP under hyperthermia and normothermia conditions. Rat hindlimbs were perfused with Krebs-Henseleit buffer containing 4.7% bovine serum albumin at 37 or 41.5 degrees C at a flow rate of 4 ml/min. Concentrations of melphalan in perfusate and tissues were determined by high performance liquid chromatography with fluorescence detection, The concentration of melphalan in perfusate and tissues was linearly related to the input concentration. The rate and amount of melphalan uptake into the different tissues was higher at 41.5 degrees C than at 37 degrees C. A physiological pharmacokinetic model was validated from the tissue and perfusate time course of melphalan after melphalan perfusion. Application of the model involved the amount of melphalan exposure in the muscle, skin and fat in a recirculation system was related to the method of melphalan administration: single bolus > divided bolus > infusion, The peak concentration of melphalan in the perfusate was also related to the method of administration in the same order, Infusing the total dose of melphalan over 20 min during a 60 min perfusion optimized the exposure of tissues to melphalan whilst minimizing the peak perfusate concentration of melphalan. It is suggested that this method of melphalan administration may be preferable to other methods in terms of optimizing the efficacy of melphalan whilst minimizing the limb toxicity associated with its use in isolated limb perfusion.

Relative dispersion of intravascular transit times during isolated human limb perfusions for recurrent melanoma

Aims We have characterized the relative dispersion of vascular and extravascular markers in the limbs of three patients undergoing isolated limb perfusions with the cytotoxic melphalan for recurrent malignant melanoma both before and after melphalan dosing. Methods A bolus of injectate containing [Cr-51] labelled red blood cells, [C-14]-sucrose and [H-3]-water was injected into an iliac or femoral artery and outflow samples collected at 1 s intervals by a fraction collector. The radioactivity due to each isotype was analysed by either gamma [Cr-51] or beta [C-14 and H-3] counting. The moments of the outflow fraction-time profiles were estimated by a nonparametric (numerical integration) method and a parametric model (sum of two inverse Gaussian functions). Results The availability, mean transit time and normalised variance (CV2) obtained for labelled red blood cells, sucrose and water were similar before and after melphalan dosing and with the two methods of calculation but varied between the patients. Conclusions The vascular space is not well-stirred but characterized by a CV2 similar that reported previously for in situ rat hind limb and rat liver perfusions. A flow-limited blood-tissue exchange was observed for the permeating indicators. Administration of melphalan did not influence the distribution characteristics of the indicators.

Relationship between limb movement speed and associated contraction of the trunk muscles

Rapid shoulder movement is preceded by contraction of the abdominal muscles to prepare the body for the expected disturbance to postural equilibrium and spinal stability provoked by the reactive forces resulting from the movement. The magnitude of the reactive forces is proportional to the inertia of the limb. The aim of the study was to investigate if changes in the reaction time latency of the abdominal muscles was associated with variation in the magnitude of the reactive forces resulting from variation in limb speed. Fifteen participants performed shoulder flexion at three different speeds (fast, natural and slow). The onset of EMG of the abdominal muscles, erector spinae and anterior deltoid (AD) was recorded using a combination of fine-wire and surface electrodes. Mean and peak velocity was recorded for each limb movement speed for five participants. The onset of transversus abdominis (TrA) EMG preceded the onset of AD in only the fast movement condition. No significant difference in reaction time latency was recorded between the fast and natural speed conditions for all muscles. The reaction time of each of the abdominal muscles relative to AD was significantly delayed with the slow movement compared to the other two speeds. The results indicate that the reaction time latency of the trunk muscles is influenced by limb inertia only with limb movement below a threshold velocity.

Periodic limb movements during sleep and restless legs syndrome in patients with ASIA A spinal cord injury

Objective: To establish the occurrence of Periodic Leg Movements (PLM) and Restless Legs Syndrome (RLS) in Spinal Cord Injury (SCI) subjects. Methods: In this study, twenty four patients were submitted to a full night polysomnography and were assessed with Epworth Sleepiness Scale and an adapted form of International Restless Legs Syndrome Scale Rating Scale (IRLS Rating Scale). Control Group (CG) was composed of 16 subjects, 50% of each sex, age: 24.38 +/- 4 years old. Spinal Cord Injury Group (SCIG) was composed of 8 subjects (29 +/- 5 years old) with a complete SCI (ASIA A) of about three and a half years of duration, 100% males. Results: 100% of SCIG had RLS compared to 17% in CG ( p < 0.0001). SCIG had 18.11 +/- 20.07 of PLM index while CG had 5.96 +/- 11.93 (p = 0.01). Arousals related to PLM were recorded in CG and SCIG. There was a positive moderate correlation between RLS and age (r = 0.5; p = 0.01), RLS and PLM (r = 0.49; p = 0.01), adapted IRLS Rating Scale and PLM index (r = 0.64; p = 0.03) and also a negative moderate correlation between Epworth Sleepiness Scale and PLM index (r = -0.4; p = 0.04) in both groups. Conclusion: RLS and PLM are common findings in SCI patients with a complete injury. (C) 2010 Elsevier B.V. All rights reserved.

Vascularized Bone Grafts for Upper Limb Reconstruction: Defects at the Distal Radius, Wrist, and Hand

Vascularized bone grafts have been successfully applied for the reconstruction of bone defects at the forearm, distal radius, carpus, and hand. Vascularized bone grafts are most commonly used in revision cases in which other approaches have failed. Vascularized bone grafts can be obtained from a variety of donor sites, including the fibula, the iliac crest, the distal radius (corticocancellous segments and vascularized periosteum), the metacarpals and metatarsals, and the medial femoral condyle (corticoperiosteal flaps). Their vascularity is preserved as either pedicled autografts or free flaps to carry the optimum biological potential to enhance union. The grafts can also be transferred as composite tissue flaps to reconstruct compound tissue defects. Selection of the most appropriate donor flap site is multifactorial. Considerations include size matching between donor and defect, the structural characteristics of the graft, the mechanical demands of the defect, proximity to the donor area, the need for an anastomosis, the duration of the procedure, and the donor site morbidity. This article focuses on defects of the distal radius, the wrist, and the hand. (J Hand Surg 2010;35A:1710-1718. (C) 2010 Published by Elsevier Inc. on behalf of the American Society for Surgery of the Hand.)