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PubMed1992

Temperatures of skin, subcutaneous tissue, muscle and core in resting men in cold, comfortable and hot conditions.

To examine the core-shell model of temperature distribution and the possible role of subcutaneous temperature in heat regulation, comprehensive temperature measurements were made on six nude resting men exposed for 2-3 h to comfort (27 degrees C), cold (15 degrees C) and heat (45 degrees C). Cold produced strong shivering and heat caused heavy sweating. Temperatures were recorded every 10 min from: esophagus, rectum and auditory canal; back muscle and thigh muscle at 20 mm and 40 mm depths; 6 subcutaneous sites; and 16 skin sites. Average temperatures at these 29 sites were tabulated at the ends of comfort, hot and cold and the onsets of sweating and shivering. Body temperature changes were slow to develop, the skin temperatures being fastest, and successively deeper tissues progressively slower. There was occasional after-drop and after-rise. The data were consistent with the core-shell concept. The temperature gradient from subcutaneous tissue to skin, which differed substantially with comfort, the onset of shivering and the onset of sweating, could serve as a regulatory signal. The data are now in computer format and may be of interest to biothermal modelers.

Adult↗
PubMed1997

Relationships between spinal mobility, physical performance tests, pain intensity and disability assessments in chronic low back pain patients.

Correlations between the Oswestry Disability Questionnaire (ODQ), the Pain Disability Index (PDI), PDI subscales PDI factor 1 (PDI 1), PDI factor 2 (PDI 2) and visual analogue scale (VAS) pain intensity on the one hand and spine range of motion measures and static and dynamic functional performance tests on the other, were studied in 52 chronic low back pain patients. Comparable groups of male and female patients were studied. A moderately significant (p < 0.01) inverse correlation was observed between the ODQ and rotation to the left even after correction for age, but not when men and women were studied separately. A significant (r = -0.480, p < 0.001) inverse correlation was observed between the repeated squatting test and pain intensity and in men both pain intensity and disability correlated (r = -0.607, p < 0.001) with this particular test. Only for the women were there moderately significant (p < 0.01) inverse correlations between disability assessments and all the physical performance tests with the exception of the static back muscle test. In the women only the isometric lifting test showed a moderately significant inverse correlation (r = -0.504, p < 0.01) with pain intensity. Such apparent gender differences in the overlap between physical performance tests and self-report disability assessments and pain intensity may be clinically relevant. The results will, however, require confirmation on larger groups of chronic low back pain patients.

Adult↗
PubMed2002

Retroperitoneoscopic nephropexy for symptomatic nephroptosis.

BACKGROUND: Open nephropexy for nephroptosis creates significant morbidity. We describe our technique for retroperitoneoscopic nephropexy and evaluate its efficacy. METHODS: Twenty-five renal units in 23 patients with symptomatic nephroptosis underwent retroperitoneoscopic nephropexy by suturing the posterior renal capsules and transfixing them to the back muscles. The diagnosis and postoperative assessment were made by typical symptoms (via patient questionnaire) and findings of intravenous urography (IVU) when the position was changed from supine to erect. RESULTS: Mean operative time was 188 min (range, 90-330). Mean narcotic use was 15.6 mg morphine. Complete resolution of symptoms occurred in 84% (21/25) renal units; 12% (three of 25) achieved partial improvement (>75% decrease of preoperative symptoms). Follow-up IVU showed that 88% of patients had a renal descent of <2 cm on standing; the others had a descent of 2-4 cm. All of the five renal units with hydronephrosis resolved completely after the operation. CONCLUSIONS: This modified technique of retroperitoneoscopic nephropexy is a minimally invasive, feasible, and highly successful option for treating patients with symptomatic nephroptosis.

Adult↗
PubMed1993

Myogenin gene disruption results in perinatal lethality because of severe muscle defect.

Myogenin is a member of the basic helix-loop-helix (bHLH) gene family and converts multipotential mesodermal cells to myoblasts. The four members of the myoD family show unique spatio-temporal expression patterns and therefore may have different functions during myogenesis. Here we inactivate the myogenin gene in order to understand its role in myogenesis. Homozygous mutations are lethal perinatally owing to the resulting major defects in skeletal muscle. The extent of disorganization of muscle tissue differs in three regions. In the latero-ventral body wall, most cells, including myogenic cells, disappear and there is rapid accretion of fluid. In the limbs, cells of the myogenic lineage exist, but they are severely disrupted, and some of them are mono-nucleate with properties of myoblasts. In contrast, there are many axial, intercostal and back muscle fibres to be seen, although fibres are mainly disorganized and Z-lines are not present in most myofibrils. These findings are evidence that myogenin is crucial for muscle development in utero and demonstrate that other members of the myogenic gene family cannot compensate for the defect.

Animals↗
PubMed2005

Out-of-plane trunk movements and trunk muscle activity after a trip during walking.

Tripping during gait occurs frequently. A successful balance recovery implies that the forward body rotation is sufficiently reduced. In view of this, adequate control of the trunk momentum is important, as the trunk has a high inertia. The aim of this study was to establish out-of-plane trunk movements after a trip and to determine trunk muscle responses. Ten male volunteers repeatedly walked over a platform in which 21 obstacles were hidden. Each subject was tripped over one of these obstacles at mid-swing of the left foot in at least five trials. Kinematics, dynamics, and muscle activity of the main trunk muscles were measured. After a trip, an increase in trunk flexion was observed (peak flexion 37 degrees). In addition, considerable movements outside the sagittal plane (up to 20 degrees) occurred. Already before landing of the blocked foot, the trunk forward bending movement was reduced, while trunk torsion and lateral rotation were still increasing. Fast responses were seen in both abdominal and back muscles, indicating stiffening of the trunk. These muscle responses preceded the mechanical trunk disturbances, which implies that these responses were triggered by other mechanisms (such as afferent signals from the extremities) rather than a simple stretch reflex. A second burst of predominantly trunk muscle extensor activity was seen at landing, suggesting specific anticipation of the trunk muscles to minimize trunk movements due to landing. In conclusion, despite large movements outside the sagittal plane, it appears that trunk muscle responses to trips are aspecific and especially aimed at minimizing trunk forward bending.

Adult↗
PubMed1994

Revascularization of calvarial, mandibular, tibial, and iliac bone grafts in rats.

Some studies have suggested that membranous bone grafts undergo less resorption than endochondral grafts, and faster revascularization of the former has been proposed as the explanation. We studied fresh syngeneic full-thickness bone grafts from calvaria, mandibula, tibia diaphysis, and iliac bone implanted in the back muscles of young Lewis rats. As a measure of the quantity of cancellous bone in grafts before implantation, the ratio of the total area of soft-tissue spaces to the total area of the graft was measured histomorphometrically. Revascularization in grafts 3 weeks postoperatively was evaluated by deposit of 141Ce-labeled microspheres. Both the quantity of cancellous bone (before implantation) and the revascularization (3 weeks postoperatively) were greater in the mandibular and iliac bone grafts than in the calvarial and tibia diaphyseal grafts. The results suggest that the anatomical area of harvest of bone graft is important regarding early revascularization, but the results do not support the theory that different embryological mode of development is the cause since mandibula (high 141Ce index) and calvaria (low 141Ce index) are of membranous origin and iliac bone (high 141Ce index) and tibia (low 141Ce index) are of endochondral origin. The difference in revascularization between the different grafts may be explained by differences in quantity of cancellous bone since cancellous bone is revascularized faster than cortical bone.

Animals↗
PubMed1994

Pax-3 expression in segmental mesoderm marks early stages in myogenic cell specification.

Specification of the myogenic lineage begins prior to gastrulation and culminates in the emergence of determined myogenic precursor cells from the somites. The myoD family (MDF) of transcriptional activators controls late step(s) in myogenic specification that are closely followed by terminal muscle differentiation. Genes expressed in myogenic specification at stages earlier than MDFs are unknown. The Pax-3 gene is expressed in all the cells of the caudal segmental plate, the early mesoderm compartment that contains the precursors of skeletal muscle. As somites form from the segmental plate and mature, Pax-3 expression is progressively modulated. Beginning at the time of segmentation, Pax-3 becomes repressed in the ventral half of the somite, leaving Pax-3 expression only in the dermomyotome. Subsequently, differential modulation of Pax-3 expression levels delineates the medial and lateral halves of the dermomyotome, which contain precursors of axial (back) muscle and limb muscle, respectively. Pax-3 expression is then repressed as dermomyotome-derived cells activate MDFs. Quail-chick chimera and ablation experiments confirmed that the migratory precursors of limb muscle continue to express Pax-3 during migration. Since limb muscle precursors do not activate MDFs until 2 days after they leave the somite, Pax-3 represents the first molecular marker for this migratory cell population. A null mutation of the mouse Pax-3 gene, Splotch, produces major disruptions in early limb muscle development (Franz, T., Kothary, R., Surani, M. A. H., Halata, Z. and Grim, M. (1993) Anat. Embryol. 187, 153-160; Goulding, M., Lumsden, A. and Paquette, A. (1994) Development 120, 957-971). We conclude, therefore, that Pax-3 gene expression in the paraxial mesoderm marks earlier stages in myogenic specification than MDFs and plays a crucial role in the specification and/or migration of limb myogenic precursors.

Animals↗
PubMed1988

Morphological studies on the erector spinae muscle in sixty consecutive scoliotic patients.

Paraspinal muscle biopsy was done on the erector spinae muscles in sixty consecutive scoliotic patients. Together with the clinical and muscle biopsy findings, these sixty patients were classified into thirty-two patients with idiopathic scoliosis, eleven patients with myopathic scoliosis, nine patients with neuropathic scoliosis, and eight patients with miscellaneous scoliosis. Of the thirty-two patients with idiopathic scoliosis, nineteen cases displayed neurogenic changes in the grouping of the Type 1 fibers and target fiber formation more common on the convex side back muscles. The myopathies consisted of central core disease, nemalin myopathy, congenital fiber type disproportion, mitochondrial myopathy, congenital muscular dystrophy, and myositis. Patients with neuropathic scoliosis all showed loss of the normal mosaic pattern and grouping of both Type 1 and 2 fibers in their muscle biopsies. This result indicates that there is a variety of neuromuscular diseases in scoliotic patients. The neurogenic changes observed more commonly on the convex side muscle of idiopathic scoliotic patients deserve further investigation.

Adolescent↗
PubMed2001

Mechanical energy analysis identifies compensatory strategies in disabled elders' gait.

Current concepts in disablement emphasize the importance of identifying mobility impairments in aging humans to enable timely intervention and, ultimately, prevent disability. Because mobility impairments are likely to result in compensatory movement strategies, recognizing and understanding those strategies may be critical in designing effective interventions for preventing disability. We sought to determine if mechanical energy methods are useful for identifying and understanding lower extremity compensatory movement strategies due to disabilities. Aleshinski's method was used to compute mechanical energy expenditure (MEE) and mechanical energy compensation (MEC) for the sagittal plane stance leg and low-back joints of healthy elders (HE) and disabled elders (DE) during preferred speed and paced (120 steps min(-1)) gait. DE subjects expended less ankle energy in late-stance and more low-back energy in mid-stance than did the HE subjects. When controlling for walking speed, the difference in ankle MEE disappeared, but mid-stance hip MEE was significantly higher for the DE subjects. Despite increased hip and low-back MEE, the DE subjects compensated hip and low-back muscles greater then HE subjects by increasing energy transferred into the pelvis, particularly when walking faster than their self-selected speed. Increased energy transfers into the pelvis during mid-stance may be a strategy used to assist in advancing and controlling the contralateral limb's swing phase. Increased trunk energy, however, may compromise dynamic stability and increase the risk of falling. We conclude that mechanical energy methods are useful for identifying and understanding compensatory movement strategies in elders with disabilities.

Adaptation, Physiological↗
PubMed1992

[application of electromyography (EMG) in recognition of lumbo-sacral back pain].

Power spectra of electromyograms (EMG) of back muscles in the lumbo-sacral area were compared in two groups of subjects. In the first one EMGs were registered in 49 young, healthy, males working in standing posture. The recordings were carried out at rest, after application of a 20 kg load and at the onset of pain. In the second group 31 subjects of both sexes and different age, suffering from intense back pain of various etiology, were investigated and compared with a group of 15 healthy persons. In the first group the power level increased after the loading, and in 42 subjects it showed further rise when the pain appeared. In the second group the power level at the range of 25 to 400 Hz, at rest, was significantly higher in the back pain patients than in healthy subjects. The results are discussed from the point of view of their applicability for the diagnosis of back pain.

Adult↗
PubMed1995

Soft system stabilization of the lumbar spine as an alternative surgical modality to lumbar arthrodesis in the facet syndrome. Preliminary results.

The authors present preliminary results in a series of 27 patients with a lumbar and/or lumbosacral facet syndrome operated on by use of the soft-system-Stabilization (SSS) according to Graf. Attention is paid to the correct selection of patients for this surgical technique. Excellent, good, satisfactory, moderate, and poor results were obtained in 19 (70%), 2 (7.5%), 5 (18.5%), 1 (3.5%), and 0 instances, respectively. The authors think that a Graf-procedure may be indicated in young to middle-aged patients with a lumbar and/or lumbosacral facet syndrome with 1.) no arthrotic changes of the facet joints, 2.) a still intact disc and/or only mild loss of intervertebral distance, 3.) well trained low-back muscles, and 4.) a clear-cut pain relief on test-anaesthesia of articular nerves and trial immobilization in a plastic jacket.

Adolescent↗
PubMed2003

Prediction of muscle performance during dynamic repetitive movement.

BACKGROUND: During long-duration spaceflight, astronauts experience progressive muscle atrophy and often perform strenuous extravehicular activities. Post-flight, there is a lengthy recovery period with an increased risk for injury. Currently, there is a critical need for an enabling tool to optimize muscle performance and to minimize the risk of injury to astronauts while on-orbit and during post-flight recovery. Consequently, these studies were performed to develop a method to address this need. METHODS: Eight test subjects performed a repetitive dynamic exercise to failure at 65% of their upper torso weight using a Lordex spinal machine. Surface electromyography (SEMG) data was collected from the erector spinae back muscle. The SEMG data was evaluated using a 5th order autoregressive (AR) model and linear regression analysis. RESULTS: The best predictor found was an AR parameter, the mean average magnitude of AR poles, with r = 0.75 and p = 0.03. This parameter can predict performance to failure as early as the second repetition of the exercise. CONCLUSION: A method for predicting human muscle performance early during dynamic repetitive exercise was developed. The capability to predict performance to failure has many potential applications to the space program including evaluating countermeasure effectiveness on-orbit, optimizing post-flight recovery, and potential future real-time monitoring capability during extravehicular activity.

Adult↗
PubMed1994

Effects of a carrageenan-induced inflammation in rabbit lumbar facet joint capsule and adjacent tissues.

The effects of experimentally induced inflammation of the lumbar facet joint capsule and adjacent tissues were investigated electrophysiologically and histologically. Type II carrageenan was injected into the receptive fields innervated by identified mechanosensitive afferent units. The multi-unit spontaneous background discharge rate showed increases that consisted of two phases over a time period of 150 min: the first phase (0-30 min) and the second phase (45-150 min). The time course of single units, identified as groups II, III and IV, and silent units, was also investigated. The silent unit discharge rates displayed a gradual increase in the first 15 min and persisted beyond 75 min. Histological examination revealed inflammatory changes in carrageenan injected tissues. In contrast, in isotonic saline injected control experiments there were no changes observed in the electrophysiological or histological studies. This study shows the effects of inflammation in rabbit lumbar facet joint capsule and adjacent tissues. The electrophysiological results show that inflammation of the facet joint and deep back muscles causes (1) increases in multi-unit discharge rate, (2) sensitization to mechanical stimuli and (3) recruitment of previously silent units. Inflammatory changes were also demonstrated histologically.

Animals↗
PubMed1996

Targeted inactivation of myogenic factor genes reveals their role during mouse myogenesis: a review.

The role of the four myogenic regulating genes Myf-5, myogenin, MyoD, and MRF4 (herculin, Myf-6) during mouse embryogenesis has been investigated by targeted gene inactivation. Null mutations for the MyoD gene generate no skeletal muscle phenotype due to a compensatory activation of the Myf-5 gene. Mice carrying a homozygous Myf-5 mutation exert considerably delayed myotome formation with unexpected consequences. While skeletal myogenesis in these mutant mice resumes normally at the onset of MyoD expression, a skeletal defect of the ribs persists. Apparently, Myf-5 and MyoD individually are not absolutely essential for skeletal muscle development, most likely because they have overlapping or redundant functions. In fact, double mutants lacking both, MyoD and Myf-5, fail to develop skeletal musculature and the muscle forming regions seem to be devoid of myoblasts. Homozygous inactivation of the myogenin gene leads to drastically reduced myofiber formation. These mice accumulate apparently normal numbers of myoblasts which are arrested in their terminal differentiation program. Myf-6 null mutant mice exhibit drastically reduced expression of Myf-5 for reasons presently unknown. The phenotype is very similar to Myf-5 mutants with an additional reduction of deep back muscles and minor alterations in sarcomeric protein isoforms. Based on the phenotypes obtained from these various gene "knock-out" mice, we now begin to understand the regulatory network and the homostatic relationship of genes which are critically involved in myogenesis of vertebrates.

Animals↗
PubMed1991

The attachments of the lumbar erector spinae.

The attachments and orientation of every fascicle of the lumbar erector spinae were determined in five cadavers and recorded radiographically. Little variation was found in the sites of muscle attachment, which enabled the construction of maps whereby these sites could be plotted on clinical radiographs or models of the lumbar spine. When all fascicles were plotted on 21 clinical radiographs using the maps previously developed, no significant difference in the orientation of fascicles was found compared with that observed in cadavers. This result vindicates the technique used to plot the location of individual fascicles of the lumbar back muscles.

Cadaver↗
PubMed1999

Development of muscle strength in relation to training level and testosterone in young male soccer players.

Isometric and functional strength of ninety-eight 11-yr-old male soccer players at an elite (E) and nonelite (NE) level were determined (3-4 times) through a 2-yr period, and the changes were related to growth and maturation. The initial isometric strength for extension with dominant leg [1,502 +/- 35 (E) vs. 1,309 +/- 39 (NE) N], extension with nondominant leg (1,438 +/- 37 vs. 1,267 +/- 45 N), extension with both legs (2,113 +/- 76 vs. 1,915 +/- 72 N), back muscles (487 +/- 11 vs. 414 +/- 10 N), abdominal muscles (320 +/- 9 vs. 294 +/- 8 N), and handgrip (304 +/- 10 vs. 259 +/- 8 N) increased by 15-40% during the period. Broad jump increased (P < 0. 05) by 15 (E) and 10% (NE). The E players had higher (P < 0.05) initial isometric strength and broad jump performance compared with NE players, and differences were maintained throughout the period (multiple ANOVA for repeated measures) also when adjustment was made for age, dimensions, testosterone, and insulin-like growth factor I (generalized estimating equations analyses). The development of strength for both E and NE players together was significantly (P < 0. 001) related to changes in serum testosterone concentrations. The present data indicate that testosterone is important for development of strength in young boys and that, independent of serum testosterone concentration, E players have developed greater muscle strength compared with NE players.

Adolescent↗
PubMed1999

Changes of contour of the spine caused by load carrying.

The development of new leisure activities such as walking has spread the use of the backpack as a means of carrying loads. The aim of this work was to present a way of defining the movements imposed on the trunk by this type of load carrying. A 20 kg load situated at the thoracic level (T9) of the trunk, was placed in a backpack (2.5 kg). The 12 subjects were average mountain guides of Auvergne region, intermediate level and complete beginners. External markers were glued to the projecting contours of the spinous processes of the C7, T7, T12, L3 and S1 vertebrae, the shin and the external occipital tuberosity (EOT). Using a Vicon 140 3-D system we measured the effective mobility of the different spinal segments in the sagittal plane during one step. For every subject, we noticed a significant decrease of the effective inter-segmental mobility (EISM) between S1-L3-T12 (p < .01) while backpacking a 22.5 kg load. A decrease of EISM also appeared at the next level between L3-T12-T7 (p < .05). An increase of the EISM between T7-C7-EOT was noted (p < .05). We supposed that strength loss of the back muscles and/or angular oscillations of the trunk could be a common cause of symptoms during backpacking. The subjects using this type of load carrying have to adopt an adequate position of the lumbar, dorsal and cervical vertebrae.

Adult↗
PubMed2006

Compositional variation of fibrous callus and joint cartilage in different internal environments.

OBJECTIVE: To evaluate the compositional variation of fibrous callus in the fracture site and the joint cavity and joint cartilage after being transplanted in the muscle pouch. METHODS: Thirty 2 month old New Zealand white rabbits (weighing 1-1.5 kg) were randomly divided into two groups: a callus transplantation group (Group A, n=15) and a cartilage transplantation group (Group B, n=15). In Group A, closed radius fracture was made and the autologous fibrous callus was transplanted in the right knee joint cavity at 12 days postoperatively. In Group B, the right knee joint cartilage of the animals was transplanted in the autologous back muscle pouches under anesthesia. Then all the animals were killed by overdose anesthetic 3 weeks after transplantation. And the transplanted fibrous callus, the healed bones in the fracture sites and the transplanted joint cartilage were obtained for assessment of compositional variation. RESULTS: Pure fibrous composition was found in the callus at the fracture sites in Group A at 12 days postoperatively. And for 11 out of the 15 animals, the fibrous callus was transformed into cartilaginous tissues after 3 weeks of transplantation, but the fibrous callus was absent in the other 4 animals. The fibrous calluses at the original site and the fracture locus were differentiated into bony tissues. Bony tissue transformation was found in the transplanted joint cartilages in the muscle pouch of all the animals in Group B. CONCLUSIONS: The fracture sites or joint cavity may facilitate callus differentiation in different ways: the former is helpful for osteogenesis while the latter for the development and maintenance of cartilages, and the muscle pouch is inclined to induce the osteogenic phenotype for cartilages.

Animals↗