Female urothelial cell carcinoma in a failed kidney graft of a male recipient.

We present a case of a male kidney transplant patient harbouring two kidney grafts of which one is functional. In the failed graft, he developed urothelial cell carcinoma with cells containing XX-chromosome, and female tumour cells were also found in the bladder. The patient underwent donor nephrectomy, was treated with epirubicin bladder instillations, and immunosuppression was tapered. Less than a year before re-transplantation a CT scan showed no abnormalities of the first graft. Transplantectomy before a second kidney transplantation is debated.

An electromyographic study of the hip muscles of transfemoral amputees in walking.

The aim of this study was to obtain insight into the electromyographic activity of the hip muscles after transfemoral amputation and to determine whether the cleaved hip muscles are still functional in locomotion. The electromyographic activity of the superficial hip muscles of both legs was studied in 11 men who had a unilateral transfemoral amputation. The intact muscles at the intact and amputated side showed the same sequence of activity as did those in healthy subjects, but during a longer period of time. The activity of the cleaved muscles with intact muscle fibers (gluteus maximus, tensor fasciae latae) was dependent on whether the iliotibial tract was reanchored. If the iliotibial tract was fixed, the same activity was found in the muscles of the patients as in those of healthy subjects. The activity of the cleaved, once biarticular, muscles (sartorius, rectus femoris, hamstring muscles, gracilis) was dependent on whether the muscles were reanchored and on the level of amputation. If the cleaved muscles were reanchored correctly, the muscles remained functional in locomotion in patients with an amputation in the distal half of the femur. In patients with high amputation levels, these muscles were almost continuously active; they probably play a role in fixing the socket.

An inverse dynamics model for the analysis, reconstruction and prediction of bipedal walking.

Walking is a constrained movement which may best be observed during the double stance phase when both feet contact the floor. When analyzing a measured movement with an inverse dynamics model, a violation of these constraints will always occur due to measuring errors and deviations of the segments model from reality, leading to inconsistent results. Consistency is obtained by implementing the constraints into the model. This makes it possible to combine the inverse dynamics model with optimization techniques in order to predict walking patterns or to reconstruct non-measured rotations when only a part of the three-dimensional joint rotations is measured. In this paper the outlines of the extended inverse dynamics method are presented, the constraints which define walking are defined and the optimization procedure is described. The model is applied to analyze a normal walking pattern of which only the hip, knee and ankle flexions/extensions are measured. This input movement is reconstructed to a kinematically and dynamically consistent three-dimensional movement, and the joint forces (including the ground reaction forces) and joint moments of force, needed to bring about this movement are estimated.

Changes in hip muscles after above-knee amputation.

To learn about the changes appearing in hip muscles after an above-knee amputation, 3-dimensional reconstructions of the hip and thigh region of 12 patients with above-knee amputations were made based on transverse magnetic resonance images. In all patients, the amputations were done at least 2 years before the study and were necessitated by trauma or osteosarcoma. The results show that, at higher amputation levels, the geometry of the once-biarticular muscles was changed. The cleaved muscles (40%-60%) and the intact muscles (0-30%) at the amputated side were atrophied. The amount of atrophy of the intact muscles at the amputated side was related to stump length. To avoid an abduction contracture in 8 patients with amputations, the iliotibial tract was not fixed. In 4 of these 8 patients, a flexion contracture was visible. If the tract was not fixed, the hip extension torque of the gluteus maximus, which inserts into the tract, decreased. As a result, the risk of appearance of a flexion contracture increased because the strongest hip flexor (iliopsoas muscle) was not involved in the amputation. Abduction contracture could be avoided only if the hip adductors were fixed accurately, especially at higher amputation levels.

Prosthetic gait of unilateral transfemoral amputees: a kinematic study.

OBJECTIVE: The prosthetic gait of unilateral transfemoral amputees. DESIGN: Case series. SETTING: Laboratory of Gait Analysis (GIGA-system of K-lab) in the Department of Rehabilitation of a university hospital. PATIENTS: Eleven men with transfemoral amputation (mean age 35.7 years) participated. The amputation was performed at least 2 years ago and was caused by trauma or osteosarcoma. MAIN OUTCOME MEASURES: Stride parameters as well as the patterns of motion of the trunk, hip, and knee joint. RESULTS: The amputees walked with a 29% lower vcomf than normal subjects. The amputees compensate the vrapid with their stride length rather than with their step rate. The amputees showed an asymmetrical walking pattern; the amputees stood a little longer on their intact leg than on their prosthetic leg. Four amputees showed an extreme lateral bending of the trunk toward the prosthetic side during the stance phase of the prosthetic leg. The rebound of the hip at the amputated side at heel strike was very small or absent. The intact knee was flexed at heel strike and remained in a flexed position during the entire stance phase. CONCLUSIONS: The amount of asymmetry of the walking pattern is related to the stump length. The amputees with highly atrophied hip-stabilizing muscles walked with an extreme lateral bending of the trunk toward the prosthetic side. There is no correlation between stride width and lateral bending of the trunk. Amputees with a short and medium stump length showed a fast transition from hip extension to hip flexion.

Three-dimensional reconstruction of the hip muscles on the basis of magnetic resonance images.

MRI in combination with three-dimensional reconstruction is pre-eminently suitable for the study of the human musculoskeletal system in vivo in an accurate and detailed way. MRI provides the possibility of studying superficial as well as deep muscles under tension in the living state. Bones, muscles, tendons and adipose tissue are clearly visible. Parts can also be distinguished within a muscle. After reconstruction of the 2-D images the geometry of the muscles and muscle parts can be visualized from different angles. This leads to a deeper understanding of the biomechanics and functional anatomy of the musculoskeletal system of the human body. In this paper the morphology of the muscles around the hip was studied in three subjects in vivo on the basis of three-dimensional (3-D) reconstructions of two-dimensional (2-D) MR images.

A comparative study of electromyograms of the masseter, temporalis, and anterior digastric muscles obtained by surface and intramuscular electrodes: raw-EMG.

Electromyographic activity was synchronously recorded by surface and intramuscular electrodes in the same muscle. The activity of the left masseter, left temporalis, and both bellies of the anterior digastric muscle was studied by this double registration technique. In rest position no electromyographic activity could be detected in any of the muscles by both techniques. Both techniques give comparable results in cyclic jaw movements. In isometric contractions, however, differences in the registered activity were observed between the surface electrode on the depressor group muscles and the intramuscularly recorded anterior digastric muscles. Silent periods evoked in the elevator muscles were of slightly longer duration when recorded by intramuscular electrodes than when recorded by surface electrodes. A protruded position of the mandible results in a silent period of longer duration than the position of the mandible in maximal occlusion during clenching for both techniques.

Influence of posture on the relation between surface electromyogram amplitude and back muscle moment: consequences for the use of surface electromyogram to measure back load.

The aim of the study was to analyse the effect of posture on the relation between EMG amplitude and moment of the back muscles in different subjects, in order to gain a better insight into the possibilities of EMG as a means of measuring individual back load. Eight healthy subjects participated in the experiments. Isometric back extensions were performed in three postures: upright standing, standing with the spine flexed, and upright sitting. In each posture the lumbar moments of three maximal voluntary contractions were measured and then exertions of 10 to 90% of maximal voluntary contraction (increments of 10) were performed. EMG signals from the back muscles were recorded with four pairs of surface electrodes located 3 cm and 6 cm lateral to the midline of the spine at the L3 level. EMG signals were full-wave rectified and averaged over 2 s intervals of constant moment. The results show that posture has a considerable influence on the relationship between EMG and the lumbar moment. Besides this, large individual differences and an influence of electrode position on the relationship were found. Therefore it is concluded that whenever EMG is to be used as a means to measure individual back load, a calibration of the EMG amplitude to lumbar moment ratio is necessary for each subject, each electrode position, and each posture. Interpretation of EMG amplitudes has to be done on an individual basis and taking influences of posture and electrode location on the EMG-lumbar moment relationship into account.

A standardized technique for the placement of electrodes in the two heads of the lateral pterygoid muscle.

The results of electromyographic research on the two heads of the lateral pterygoid muscle depend largely on correct placement of the electrodes. Measurements were carried out on 24 male and 27 female skulls of known age and sex to determine the direction and depth of penetration for the placement of wire electrodes in the two heads of the lateral pterygoid muscle separately. The method of placement was simulated on human dissecting room material. With the use of a modified dental facebow, endodontic needles were placed in the direction of the two heads of the lateral pterygoid muscle in 11 human cadavers. The point of penetration was the most cranial point of the lower border of the zygomatic arch, lateral to the sigmoid notch of the mandible; after dissection over 80% of the needles proved to be placed correctly. The technique has since been used over 60 times on both heads of the lateral pterygoid muscle in volunteering dental students, dentists, and patients with symptoms of craniomandibular dysfunction. The technique interferes with the maximal opening of the mouth, which was reduced by about 10 mm. Subjects suffered slight inconveniences after the removal of the electrodes at the end of the test procedures. These inconveniences consisted of stiffness in the jaws and muscle soreness. Hematomas or infections did not occur.

The shape of the mandible in the domestic sheep: a biomechanical analysis using EMG as an estimator of muscle force.

Analysis of the maximal loads to which a skeletal element is subjected in vivo offers attractive possibilities of explaining the shape of the element. The underlying assumption is that the element will be constructed in such a way that deformations (strains) which result from mechanical stress will not exceed certain limits and that stresses will be evenly distributed. The sheep mandible shows a number of characteristic morphological features that invite this kind of explanation. We investigated the patterns of activity of the masticatory musculature by multichannel electromyography, expressing the activity of any particular muscle during a given interval as a percentage of the highest activity recorded for the muscle in question. In combination with data on the physiological cross sections of the muscles, which provide indications of the maximal forces which can be exerted by the muscles, three-dimensional patterns of relative muscular forces acting on the mandible can be constructed for successive stages of a masticatory cycle. No absolute forces can be measured or even estimated by this technique. A two-dimensional finite element model of the mandible was designed, by means of which predictions of stress and strain resulting from the muscular loading can be made. Calculations were based on the highest loads that occurred, during the power stroke of rumination. It is concluded that mechanical loading of the mandible provides a partial explanation of the form, and that a more satisfactory model should include other than purely mechanical influences.

Critical periods in the prenatal morphogenesis of the human lateral pterygoid muscle, the mandibular condyle, the articular disk, and medial articular capsule.

This study was prompted by the renewed clinical interests in understanding the natural history or early morphogenesis of the human temporomandibular joint. Using histologic preparations of 52 representative human embryos and fetuses, each of the major components of the joint was systematically assessed for its changing structure and related to an approximate time scale. The emergence and continued morphogenesis of the joint articular fossa, mandibular condyle, disk, capsule, lateral pterygoid muscle fibers, and both joint cavities occur in regular temporal and spatial pattern. A key observation from this study of embryos and fetuses ranging in age from 32 days to 22 weeks is that each of the component parts of the TMJ progressively emerge with some kind of continuity from a common mass of embryonic mesenchyme interposed between the future temporal bone and mandibular regions. The observations of this study lead to the suggestion that significant developmental disturbances to this common tissue mass or "developmental field" can lead to anomalous morphogenesis of those structures expected to emerge over time from the "developmental field" of the temporomandibular joint. Timing and the identification of a critical time period for the joint are important variables. This study identifies the critical period in the early morphogenesis of TMJ structures as generally falling between the early 7th and 11th prenatal weeks.

The spectrum of splenogonadal fusion. Case report and review of 84 reported cases.

Splenogonadal fusion is a rare congenital malformation in which there is an abnormal fusion between the spleen and the gonad or derivatives of the mesonephros. It can occur in both sexes but has been reported far more frequently in males. There are two types of this malformation: the continuous and the discontinuous type, depending on the presence or absence of a structural connection between the regular spleen and the ectopic splenic tissue that is fused to the gonad. In one-third of all reported cases splenogonadal fusion is associated with other congenital defects. This association is predominantly found within the continuous type. Peromelia is present in a high percentage of cases, varying from total absence of all limbs to absence of parts of the lower limbs. On the basis of a case report and a review of 84 published cases, the causal, pathogenetic and nosologic aspects of this malformation are discussed. We hypothesise that splenogonadal fusion with peromelia and splenogonadal fusion without peromelia represent two ends of one spectrum determined by the developmental stage during which the causal factor acts.

Muscle activity at the ilio-sacral articulation of frogs.

Electromyographic recording indicates that the sequence of muscle firing around the ilio-sacral joint is similar for three species of frogs during locomotion, despite differences in gross morphology at the articulation. The ilio-sacral musculature is most active during the take-off phase of a jump, and there is a correlation between the degree of muscle activity and height of jump. This muscle activity is involved in aligning the center of mass of the frog with the direction of the propulsive force of the jump. The firing pattern of the ilio-sacral musculature is essentially similar during swimming and jumping, and suggests that differences in medium (water vs. air) are responsible for differences in propulsive thrust in the two types of locomotion.