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At least 505 records · Page 28Linked to original sources
PubMed1997

Natural occurrence of fast- and fast/slow-muscle chimeric fibers in the expression of troponin T isoforms.

Rhomboideus, one of the back muscle tissues, and its single fibers were studied in chickens by immunostaining with antisera against fast- and slow-muscle-type troponin T isoforms. Nonuniform distribution of slow-muscle-type isoforms was for the first time detected in single fibers isolated from the muscle, although fast-muscle-type troponin T isoforms were distributed over the whole length of the fiber. Based on these observations, we conclude that fast- and fast/slow-muscle chimeric fibers exist in normal skeletal muscle tissue and that the existence of chimeric fibers is direct evidence showing that myonuclei subjected to different determination in troponin T isoform expression can together form a single muscle fiber.

Aging↗
PubMed1996

Mechanical and biochemical injury of spinal nerve roots: a morphological and neurophysiological study.

Compression may induce morphological and neurophysiological changes in nerve roots. However, it has also been demonstrated experimentally that nucleus pulposus, without any compression, may induce similar changes when applied epidurally. The present study was undertaken to examine the morphological and functional effects of autologous nucleus pulposus and the combination of nucleus pulposus and compression in a pig model. Nucleus pulposus from a lumbar disc in the same animal was applied epidurally around the first sacral nerve root in the pig, with or without a specially designed constrictor. After 1 week, nerve root conduction velocity was determined in the exposed and in the contralateral control nerve root by local electrical stimulation and EMG recordings in the back muscles. Nerve root specimens were processed for blinded light-microscopic evaluation. There was a significant reduction in nerve conduction velocity for all exposed nerve roots as well as contralateral control nerve roots when nucleus pulposus had been applied. There were no statistically significant differences between the nerve conduction velocities recorded following the combined application of nucleus pulposus and compression and those recorded after application of nucleus pulposus alone. The reductions were similar to the reduction induced by the constrictor per se, as seen in a previous study. In all series there was also a decrease in conduction velocity in the control nerve roots, in contrast to previous studies. Light microscopy demonstrated axonal changes only in nerve roots exposed to the constrictor. In conclusion, both epidural nucleus pulposus and compression may induce a significant reduction in nerve conduction velocity. The combination, however, of these two agents does not increase the magnitude of such dysfunction. The potency of nucleus pulposus to induce changes in nerve roots after epidural application was further indicated by the fact that reduction in nerve conduction velocity also occurred in the contralateral control nerve roots in this series. The histological data suggest that axonal injury can not alone explain the reduction in nerve conduction velocity, and that the morphological basis for the functional changes must be sought at the subcellular level.

Animals↗
PubMed1999

A posterior approach for inspection of reduction of sacroiliac joint disruption.

This anatomic study was undertaken to describe a new posterior approach enabling direct inspection of reduction of sacroiliac joint disruption (SIJD), and guidance of iliosacral screw placement. The reduction of SIJD is usually monitored by inspection of the opposing sacrum and ilium at the posterior margin of the greater sciatic notch and there is a relative lack of information concerning inspection of reduction of SIJD from the posterosuperior aspect of the sacroiliac joint surface. Ten cadavers were dissected to determine the possibility of inspecting reduction of SIJD from the posterosuperior aspect of the sacroiliac joint by means of a posterior approach which passed immediately lateral to the deep back muscles and the fifth lumbar transverse process. The results indicated that the posterosuperior aspect of the sacroiliac joint surface and sacral ala can be directly palpated or visualised. This approach facilitates improved access for inspection of reduction of SIJD and guidance of iliosacral screw placement.

Aged↗
PubMed1993

Age-related behavioural, neurochemical and radioligand binding changes in the central 5-HT system of Sprague-Dawley rats.

Mature (3-4 months) and aged (18-19 months) Sprague-Dawley (SD) rats were treated with 5-HT receptor agonists and drug-induced behaviours monitored. The 5-HT2/1C agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), induced wet dog shakes and back muscle contractions which were significantly increased in aged, compared to mature, rats, suggesting an age-related enhancement of 5-HT2 receptor function. In contrast, the selective 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) induced forepaw treading, flat body posture, hypothermia and hyperactivity which were not significantly different in aged compared to mature rats. Levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus and frontal cortex were measured using high performance liquid chromatography with electrochemical detection. There were no age-related changes in hippocampal 5-HT or 5-HIAA. However both 5-HT and 5-HIAA were increased in the frontal cortex of aged SD rats. 8-OH-DPAT reduced 5-HIAA in both regions examined in mature rats, an effect which was attenuated in the aged rats, suggesting an age-related reduction in presynaptic 5-HT1A receptor function. DOI did not induce any changes in 5-HT or 5-HIAA in either of the regions examined. Radioligand binding studies with [3H] ketanserin showed there to be no significant age-related changes in cortical 5-HT2 receptor density or affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1986

[Static equilibrium and function of the spine].

The erect posture of man is not due to a static rigidity of the vertebral column, but to an extremely dynamic function of the whole locomotor system of the trunk, especially the multiple biomechanical and functional possibilities of the vertebral column. Vertebrae intervertebral disks, ligaments (vertebral motor segment; Junghanns, 1966), back muscles, and the adjacent organ systems have to be considered as a functional unit. The erect posture is one of the most decisive acquisitions in the phylogenetic development of man. The vertebral column starts its adaption to this condition already during the last embryonal months by rearranging the small lumbar vertebral joints, beginning with the transition between thoracic and lumbar spine. In many cases this adaption is not finished and remains incomplete in the region of transition between lumbar and sacral spine. Only the erect posture has released the hands and made possible the use of tools and the evolutionary progress of the brain which is closely connected to this ability. This most recent phylogenetic adaption of a particularly loaded region has produced a weak point in the construction of our bodies. This is the price we have to pay for our erect posture which has been essential to the development of the specific human way of life, i.e. the formation of language and culture.

Adult↗
PubMed2000

Detection of subdural placement of epidural catheter using nerve stimulation.

PURPOSE: To report the detection of a subdural catheter placement using nerve stimulation through an epidural catheter. CLINICAL FEATURES: An 85-yr-old gentleman was scheduled for radical cystectomy and creation of an ileal conduit. Combined general anesthesia and regional technqiue was selected. An epidural catheter (19 G Arrow Flextip Plus) was inserted prior to induction of general anesthesia. Intra-operatively, the patient received 5 mg morphine and 10 ml bupivacane 0.5% via the epidural catheter. The patient remained hemodynamically stable throughout the operation and did not require intravenous opioids. The patient was discharged to the ward with an order for epidural morphine for pain control. The next day, the patient remained comfortable. As an ongoing quality assessment to survey the success rate of epidural catheters at our institution, all patients are invited to have their catheter assessed using an electrical epidural stimulation test. Electrical stimulation (1-10 mA) with a segmental motor response (truncal or extremities movement) indicates that the catheter is in the epidural space. No motor response indicates that it is not. In this case, subdural catheter placement was suspected because a diffuse motor response including right anterior chest wall, back muscle, and bilateral lower extremities was observed using only 0.3 mA. Subdural catheter placement was subsequently confirmed by a radiograph showing a very thin film of dye spreading cephalad and caudad over many segments. CONCLUSION: This new electrical test helps to detect subdural placement objectively.

Aged↗
PubMed1997

[Spondylolysis and spondylolisthesis and sports].

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.

Adult↗
PubMed2004

Magnitude of abdominal incision affects the duration of postoperative ileus in rats.

BACKGROUND: The pathogenesis of reduced postoperative ileus (POI) in laparoscopic gastrointestinal (GI) surgery still remains controversial. The aim of this study was to investigate the effect of surgical incision on postoperative ileus. METHODS: The effects of length, depth, and site of the incision on GI transit were compared using the geometric center of 51Cr in rats. The inhibitory mechanism of abdominal incision on GI transit also was studied. RESULTS: The findings showed that 5 cm of abdominal skin and the 5-cm back muscle incision had no significant effect on GI transit. However, the 5-cm abdominal muscle-fascia incision and a 5-cm laparotomy significantly delayed GI transit. Gastrointestinal transit after a 5-cm laparotomy was significantly delayed, as compared with that of a 1-cm laparotomy regardless whether intestinal manipulation was performed or not. Guanethidine and yohimbine, but not propranolol, significantly improved the impaired GI transit after a 5-cm laparotomy. CONCLUSIONS: The results suggest that the longer and deeper abdominal incision more profoundly inhibits GI transit. The inhibitory effect of abdominal incision is mediated via the activation of the somatosympathetic reflex and alpha-2 adrenoceptors.

Abdominal Injuries↗
PubMed2006

Direct repair for treatment of symptomatic spondylolysis and low-grade isthmic spondylolisthesis in young patients: no benefit in comparison to segmental fusion after a mean follow-up of 14.8 years.

The aim of the present study was to assess the long-term clinical, functional, and radiographic outcome of direct repair of spondylolysis using cerclage wire fixation according to Scott in young patients with symptomatic spondylolysis or low-grade isthmic spondylolisthesis as compared to the outcome after uninstrumented posterolateral in situ fusion. Twenty-five out of 28 patients of the direct repair group (89%) and 23 out of 28 of the fusion group (82%) were available for follow-up examination. The assessment by independent observers included a structured interview (Oswestry questionnaire [ODI], visual analogue scale, SRS questionnaire), a clinical examination, functional testing, plain radiography, and MRI. The groups were comparable as to the mean age at operation (18.2 vs. 16.2 years.), the follow-up time (14.8 vs. 15.0 years), and the amount of preoperative slip (7.2 vs. 13.1%). The mean ODI and SRS total scores were significantly better in the fusion group (4.3 [0-16] and 96 [57-117]) as compared to the direct repair group (11.4[0-52] and 87[53-107]; P=0.02 and P=0.011, respectively). In functional testing, both groups reached normal values for abdominal and back muscle strength. The lumbar spine flexion and extension ROM was decreased in both groups showing no statistical difference between the groups. Significant progressive narrowing of the olisthetic disc was detected on the plain radiographs after direct repair. On the flexion-extension radiographs, in the direct repair group, the mobility in the lytic/olisthetic segment was decreased in comparison to normal values from the literature. The mobility at the level above the operated segment was decreased in the direct repair group as compared to the fusion group (P=0.057). On T2-weighted MR images in the direct repair group, the signal intensity of the disc below the affected vertebra was decreased in 17/23 (74%) patients. There was no difference between the groups in the nucleus signal intensity of the adjacent disc above the operated segment. No association between the disc degeneration on MRI and the outcome of the patients could be established. In the direct repair group the following complications were seen: transient nerve root irritation (2), superficial infection (1), UTI (1); in the fusion group the complications were: subcutaneous seroma (2) and UTI (1). There were six re-operations, cerclage removal(4), conversion into segmental fusion(2) in the direct repair group, and one re-operation, instrumented respondylodesis, in the fusion group. In conclusion, the results of direct repair of the spondylolysis using cerclage wire fixation according to Scott were very satisfactory in 76% of the patients after a mean follow-up of 14.8 years. After direct repair, the ODI deteriorated with time leading to a clinically moderate but statistically significant difference in favour of segmental fusion. Lumbar spine mobility was decreased after direct repair. Secondary segmental instability above the spinal fusion was not detected. The procedure does not seem to be capable of preventing the olisthetic disc from degeneration. The theoretical benefits of direct repair could not be proven.

Adolescent↗
PubMed1998

Surgical results after soft system stabilization of the lumbar spine in degenerative disc disease--long-term results.

After having reported preliminary results of soft system stabilization according to Graf in a series of 27 patients with degenerative disc disease of the lumbar spine in early 1995 the authors report long term clinical and radiological results of this patient series (n = 25). At a mean period of postoperative observation of 50 months excellent, good, satisfactory, moderate and poor results were obtained in 62, 9%, 11, 1% and 11, 1%, 7, 4% and 7, 4% of the patients, respectively. The well-known phenomenon of loss of disc height at the level of posterolateral fusion and instrumentation as well as overcharge of adjacent segments were not observed after soft system stabilization. Regional as well as global lumbar lordosis were maintained and, although statistically not significant, an increase of intervertebral distance was observed in adjacent segments in flexion of the lumbar spine. These phenomena might represent pressurization of instrumented as well as adjacent discs after the insertion of ligament prostheses. It is the impression of the authors, that the Graf technique leads to good surgical results in degenerative disc disease with destabilization of lumbar motion segment(s) if the following criteria are strictly respected: 1. No or only mild arthrotic changes of the facet joints 2. Preferably minor disc degeneration/only mild loss of intervertebral distance. 3. Well trained low back muscles and 4. A clear-cut, repeatedly demonstrated pain-relief on trial anaesthesia of the corresponding articular nerves and while wearing a probatory jacket.

Adolescent↗
PubMed2004

Enhancement of recombinant human bone morphogenetic protein-2 (rhBMP-2)-induced new bone formation by concurrent treatment with parathyroid hormone and a phosphodiesterase inhibitor, pentoxifylline.

We investigated the enhancement of new bone |formation elicited ectopically by recombinant human bone morphogenetic protein-2 (rhBMP-2), using parathyroid hormone (PTH) and a phosphodiesterase inhibitor (PDEi), pentoxifylline (PTX), in an animal model. Collagen sponge sheet discs containing rhBMP were implanted onto the back muscles of mice. PTX alone (200 mg/kg body weight [BW]), PTH(1-34) (10 microg/kg BW), PTX plus PTH (200 mg/kg BW and 10 microg/kg BW, respectively), or vehicle (control) were injected subcutaneously daily for 3 weeks after implantation. At the end of this period, rhBMP-2-induced ectopic ossicles were harvested from each group of animals. Ossicles from the PTX-treated group were significantly larger in size, with unchanged bone mineral density (BMD), as compared with the ossicles from the controls. In contrast, the ossicles from the PTH-treated group had significantly higher BMD, but showed no difference in size when compared with those from the control animals. The ossicles of the PTX + PTH treatment group were significantly larger than those of the control and PTH treatment groups. In addition, the BMD of the harvested tissues from the PTX + PTH treatment group was signifi-cantly higher than that of tissues from the control and PTX treatment groups. Although the calcium content of ossicles was significantly higher in the PTX-, PTH-, and PTX + PTH-treated groups than in the control group, the Ca content of ossicles from the PTH + PTX-treated group was highest (two times that of controls), followed by the PTH- and PTX-treated groups.

Animals↗
PubMed2005

The effects of heat on the biological activity of recombinant human bone morphogenetic protein-2.

This study was designed to investigate effects of heat on the bone-inducing activity of recombinant human bone morphogenetic protein (rhBMP)-2. rhBMP-2 samples were heated at 50, 70, 90, or 100 degrees C for 15 min, or 1, 2, 4, or 8 h, or autoclaved at 120 degrees C for 15 min. The bone-inducing activity of the rhBMP-2 before and after heating was assayed in in vivo and in vitro systems. For the in vivo assay, 5 microg rhBMP-2 samples were impregnated into porous collagen disks (6 mm in diameter, 1 mm thickness), freeze dried, and implanted into the back muscles of ddY mice. Three weeks later, the implant was harvested from the host and examined for ectopic new bone tissue by radiography. The new bone mass was quantified by single-energy X-ray absorptiometry. The in vitro activity of the rhBMP-2 was assayed by adding the BMP sample at a concentration of 100 ng/ml to cultures of MC3T3-E1 cells. After 48 h, the alkaline phosphatase activity was measured. After heating at 50 degrees or 70 degrees C, no significant reduction in bone-inducing activity was noted in either in vivo or in vitro assay systems unless the protein was exposed to sustained heat at 70 degrees C for 8 h, based on in vitro assay data. However, heating above 90 degrees C and for longer periods led to a decrease in the biological activity of the rhBMP-2 in a time- and temperature-dependent manner. rhBMP-2 was rendered inactive when exposed to temperatures at or in excess of 120 degrees C.

Alkaline Phosphatase↗
PubMed1983

The distance between the load and the body with three bi-manual lifting techniques.

Studies were made of two different techniques of bi-manual lifting with bent legs (A and B) and a technique of lifting with the back bent and the Knees almost extended (C). With technique A, the trunk was almost vertical, while with B it was erect and more forward inclined and the heel of the front foot kept in contact with the support. Two healthy subject samples (n = 18 and n = 16 respectively) were studied, both employing a force platform; with the second sample the back muscles were also evaluated by electromyography. The distance Delta L between the lines of gravity of the body and the load at the start of the lifts was shortest with technique A and longest with C. This was true whether the position of the feet was chosen spontaneously or was identical for all three techniques. The distance of the load from the body during the lifting movement was directly related to the distance at the start of the lift: the further away the load was at initiation of the lift, the further away it remained throughout the rest of the lift. A request to lift as close to the load as possible had a positive effect in shortening Delta L , but the amount of previously received instruction in lifting technique did not correlate with the spontaneously chosen Delta L.

Journal Article↗
PubMed1984

Use of EMG in a kinesiological study in industry.

The study was conducted in an automobile upholstery plant which manufactures interior trim panels and seat covers. The job was one which required workers to lean repetitively across a 965 mm (38 in) high flat table-like die while securing sheets of material to the die. Two employees in the embossing department volunteered to participate in a comparative evaluation of the accumulation of low back fatigue from working for a full day using a die with a 914 mm (35 in) maximum reach requirement versus that of a die with a 813 mm (32 in) maximum reach requirement. Electromyography (EMG) of the low back muscles was the measure used for the evaluation. EMG recordings from static muscular contractions were made at selected intervals for an 8 h work day while maintaining normal production. Integrated EMG amplitude and power frequency shifts formed the bases for comparison. The integrated EMG amplitude increase over the course of the day was 47% and 100%, respectively, for the two subjects while working with the 813 mm (32 in) die; the respective EMG amplitude increases for the day while working with the 914 mm (36 in) die were 83% and 263%. None of the power frequency shifts exceeded a predetermined minimum level considered necessary to indicate fatigue. As a result of this study, the plant reduced as much as possible the maximum reach required on every die in the embossing department in order to reduce worker fatigue.

Journal Article↗
PubMed1991

Loads on the body during static tasks: software incorporating the posture targetting method.

The biomechanical evaluation of loads on the body is one of the tools that facilitate the assessment of manual handling tasks. A computer program has been developed to determine moments about joints during static tasks. It differentiates between flexion/ extension, rotation and adduction/abduction requirements so that the major efforts can be identified and compared with population strength data. It also evaluates loads on the spine and within low-back muscles for purposes of comparison with many manual handling studies. Posture and a variety of external forces are input to the system with a choice of two interchangeable methods: one uses a 'CODA' scanner for on-line posture recording in the laboratory, the other is 'posture targetting', a pen-and-paper method adapted for the computer.

Journal Article↗
PubMed1994

An evaluation of comfort of a bus seat.

The aim of this research was to evaluate the comfort of a passenger seat for a new type of bus. A fuzzy set model of a multistage comfort scale (MCS) was adopted for the assessment of comfort, together with the techniques of human back shape and EMG measurements as well as posture analysis. The subjects were 30 university students. It is concluded that MCS is a rapid but comprehensive evaluation method for single chair evaluation. The overall rating of MCS is 0.532, which is acceptable under the conditions of the prototype evaluation. The seat profile fits better with the back curve of subjects who had higher comfort rating in the way that the upper profile of the seat coincides with the human back curve and the lower part of the profile intersects the human back curve in the lumbar region; here the human back curves were measured in the slumped sitting posture. There was a significant difference in the EMGs of back muscles between the two sitting postures (sitting upright and the slumped sitting posture) at all the seat heights.

Journal Article↗
PubMed1994

The anatomy of the iliolumbar ligament.

During routine autopsies and anatomical dissections the anatomy of the iliolumbar ligament was studied and determined. In previous studies and literature, the ligament has been described to consist of three to five parts. We found the ligament to consist of only two parts: the anterior part and the posterior part, both attaching to the L5 transverse process. The insertion of the ligament has also been mentioned previously as attaching to the iliac crest. Both parts of the ligament were found to inset to the upper part of the iliac tuberosity, significantly lower than the iliac crest. The iliolumbar ligament cannot be visualized from the dorsal side before dissecting through all the lower back muscles and their fascias. We also found no evidence of any ligament part attaching to the L4 transverse process.

Adolescent↗
PubMed1994

Bending and compressive stresses acting on the lumbar spine during lifting activities.

Cadaveric studies have shown that intervertebral discs and ligaments are most vulnerable to injury when loaded simultaneously in bending and compression. The purpose of the present experiment was to measure bending and compressive stresses acting on the lumbar spine during forward bending and lifting activities, and to identify those aspects of lifting which increase the risk of injury. Twenty-one men and eighteen women lifted objects from the ground while the following parameters were varied: the angle of the knees ('squat' lift or 'stoop' lift), the mass of the object, its bulk, its distance in front of the feet, its distance away from the sagittal plane, and the speed of movement. Spinal compression was assessed by measuring the peak extensor moment generated by the back muscles and fascia during the lift. Extensor moment was calculated from the EMG activity of the erector spinae muscles, using corrections for muscle length, contraction velocity and electro-mechanical delay. The bending moment ('bending torque') acting on the intervertebral discs and ligaments was quantified by comparing dynamic measurements of lumbar flexion, obtained with the '3-Space Isotrak', with the normalised bending properties of cadaveric lumbar spines. Results showed that stoop lifting reduced the peak extensor moment by about 10% compared to squat lifting, but increased the bending torque by about 75%. Extensor moment and bending torque both increased substantially with increasing mass, bulk and distance from the feet. Non-sagittal plane lifts increased the bending torque by about 30%. The fastest lifts increased peak extensor moment by 60% but did not increase bending torque. We conclude that complex spinal loading during lifting tasks depends as much on the speed of movement, and the size and position of the object lifted, as on its mass. Analyses of spinal loading which consider only compressive forces do not give a full indication of the risk of injury to the intervertebral discs and ligaments.

Adult↗