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At least 541 records · Page 30Linked to original sources
PubMed2006

Ectopic bone formation in nude rats using human osteoblasts seeded poly(3)hydroxybutyrate embroidery and hydroxyapatite-collagen tapes constructs.

PURPOSE: The aim of this study was to evaluate the ectopic bone formation using tissue engineered cell-seeded constructs with two different scaffolds and primary human maxillary osteoblasts in nude rats over an implantation period of up to 96 days. MATERIAL AND METHODS: Collagen I-coated Poly(3)hydroxybutyrate (PHB) embroidery and hydroxyapatite (HAP) collagen tapes were seeded with primary human maxillary osteoblasts (hOB) and implanted into athymic rnu/run rats. A total of 72 implants were placed into the back muscles of 18 rats. 24, 48 and 96 days after implantation, histological and histomorphometric analyses were made. The osteoblastic character of the cells was confirmed by immunocytochemistry and RT-PCR for osteocalcin. RESULTS: Histological analysis demonstrated that all cell-seeded constructs induced ectopic bone formation after 24, 48 and 96 days of implantation. There was more mineralized tissue in PHB constructs than in HAP-collagen tapes (at day 24; p < 0.05). Bone formation decreased with the increasing length of the implantation period. Osteocalcin expression verified the osteoblastic character of the cell-seeded constructs after implantation time. No bone formation and no osteocalcin expression were found in the control groups. CONCLUSIONS: Cell-seeded constructs either with PHB embroidery or HAP-collagen tapes can induce ectopic bone formation. However, the amount of bone formed decreased with increasing length of implantation.

Animals↗
PubMed1999

Estimating net lumbar sagittal plane moments from EMG data. The validity of calibration procedures.

In the present study the validity of EMG based methods to estimate the net moment working at the lumbar spine was investigated. Eight subjects performed a series of static and dynamic tasks. EMG was recorded from 8 locations over the back muscles. At the same time force platform and kinematic data for a linked segment analysis were collected. The net moment at the lumbar spine was calculated from the latter data and compared to EMG based estimates of the same moment. These estimates were derived from a linear regression between the EMG amplitudes and the net moments obtained during static ramp calibrations. It appeared that calibration in several postures, covering the range occurring in the tasks studied, and in a posture in the middle of this range, yielded estimates of the group averaged 10th, 50th, and 90th percentile of the net moments which were within 10% of the real value. The explained variance obtained in the calibration procedure proved not to be a good indicator of the validity of the procedure.

Adult↗
PubMed1997

Tissue water content in rats measured by desiccation.

Tissue water content was determined by desiccation to constant weight at 40 degrees-50 degrees C in 14 tissues from two groups of rats weighing 200-250 and 270-430 g, respectively. The water content (mean +/- SE; ml/g) was highest in testes (0.861 +/- 0.002) and lowest in adipose (0.183 +/- 0.017) followed by bone (0.446 +/- 0.017) and skin (0.651 +/- 0.007). The average water content in the remaining tissues was 0.763 (+/- 0.003). Upon correction for the water content of residual tissue blood, significant difference between the uncorrected and corrected tissue water was observed for spleen, lungs, kidneys, heart, liver, and brain. Tissue water was independent of body weight, and was the same for right and left kidneys as well as testes and bone. Whereas the position of the muscle (back, abdomen, hindlimb) and adipose tissue (perirenal and subcutaneous) had no influence on water content, for skin, a slight difference was found between back and abdomen. In general, the current results are in agreement with composite literature values, but provide in one study data for all tissues used in the development of physiologically based pharmacokinetic models of rat.

Animals↗
PubMedDate not supplied

Myofascial pain syndrome and trigger-point management.

BACKGROUND AND OBJECTIVES: Myofascial pain syndrome (MPS) is a common condition often resulting in referral to a pain clinic. The epidemiology, pathogenesis, and various diagnostic tools are reviewed, and a variety of treatment methods are discussed. METHODS: Extensive periodical literature and textbooks are reviewed, and selected manuscripts are critically analyzed. RESULTS: The incidence of MPS with associated trigger points appears to vary between 30 and 85% of people presenting to pain clinics, and the condition is more prevalent in women than in men. Patients complain of regional persistent pain, ranging in intensity and most frequently found in the head, neck, shoulders, extremities, and low back. Muscle histologic abnormalities have been described in some studies. Similarly, electromyographic, thermographic, and pressure algometric studies have inconsistently identified abnormalities. A multidisciplinary approach to treatment appears to be most beneficial and may include such modalities as trigger-point injections, dry needling, stretch and spray, and transcutaneous electrical nerve stimulation. CONCLUSIONS: The definitive pathogenesis of MPS is currently unknown, and no single diagnostic method is consistently positive. While trigger-point injection is the most widely employed method of treatment, other modes of therapy have also proved to be effective.

Adult↗
PubMed2000

Movement-related potentials in the human spinal cord preceding toe movement.

OBJECTIVES: A method by which potentials related to voluntary movement can be recorded noninvasively from the human spinal cord is presented. METHODS: A novel signal processing technique performed on signals recorded by surface electrodes placed over the spinal column was used to filter time-locked back muscle noise, so that the only remaining signals were the spinal movement-related potentials from the brain to the limbs and vice versa. RESULTS: The signals obtained from 7 subjects using this technique are shown and temporally compared with movement-related cortical potentials (MRCP) and muscle electromyogram. It is demonstrated that the spinal signal starts approximately 600 ms before the actual movement, and that some features of this signal correspond to changes in cortical potentials. CONCLUSIONS: These findings imply that the spinal cord is not a simple command-carrying medium from the brain to the limbs, and implies that some computational activities take place at the spinal cord level.

Adult↗
PubMed2001

Enhancement of bone morphogenetic protein-2-induced new bone formation in mice by the phosphodiesterase inhibitor pentoxifylline.

Porous collagen disks (6 mm diameter, 1 mm thickness) were impregnated with recombinant human bone morphogenetic protein-2 (rhBMP-2) (5 microg/disk) and implanted onto the back muscles of mice. Pentoxifylline (PTX), which is a methylxanthine-derived inhibitor of phosphodiesterases (PDEs), or vehicle, was injected (5, 25, 50, 100, 200, and 300 mg/kg body weight/day) into the mice subcutaneously once a day for 3 weeks from the day of implantation of the bone morphogenetic protein (BMP)-laden disks. The rhBMP-2-induced ectopic ossicles were harvested and examined using radiographic, histological, and biochemical methods to determine size, bone quality, and calcium content. When compared with controls, ossicles from mice treated with >50 mg/kg per day of PTX were significantly larger in size and had a greater calcium content. However, no differences were noted in mice treated with lower doses (5 and 25 mg/kg per day) of PTX. The temporal sequence of the bone-forming process was unchanged by PTX based on histological examination. The histology of the ossicles from high- and low-dose PTX-treated mice was essentially identical to that observed in the control mice. These experimental results indicate that PTX enhanced the bone-inducing capacity of BMP-2. The underlying mechanism of action most likely involves the inhibition of intracellular phosphodiesterases and a resulting elevation of the intracellular content of cyclic nucleotides. Further studies are warranted to understand how BMP-induced bone formation is pharmacologically modified by PTX.

Animals↗
PubMed2002

Effect of phosphodiesterase inhibitor-4, rolipram, on new bone formations by recombinant human bone morphogenetic protein-2.

Collagen sponge disks (6 mm diameter, 1 mm thickness) were impregnated with recombinant human bone morphogenetic protein-2 (rhBMP-2) (5 microg/disk) and implanted onto the back muscles of mice. Ten or 20 mg/kg per day of Rolipram, a selective inhibitory agent to phosphodiesterase type 4 (PDE-4), or vehicle, was injected subcutaneously into the host mice for 3 weeks. After treatment, rhBMP-2-induced ectopic ossicles were harvested and examined by radiographic and histologic methods to determine the size, bone quality, and mineral content of the ossicles. The ossicles from a group treated with 20 mg/kg per day Rolipram were significantly larger in size and higher in bone mineral density (BMD) and bone mineral content (BMC) than the control samples. No significant differences were noted in mice treated with 10 mg/kg per day of Rolipram. Histologically, ossicles from the high-dose (20 mg/kg per day) Rolipram-treated group showed densely packed, thicker trabeculae when compared with those from the control group. These experimental results indicate that the PDE-4 inhibitor, Rolipram, may enhance the bone-inducing capacity of BMP-2 in mesenchymal cells. This in turn may result in increased responsiveness to BMP-2 and point to a potential use of PDE-4 inhibitors for the promotion of rhBMP-dependent bone repair.

Animals↗
PubMed2003

Transplantation of skin fibroblasts expressing BMP-2 promotes bone repair more effectively than those expressing Runx2.

We investigated the osteogenic potential of skin fibroblasts that overexpressed BMP-2 or Runx2 by using adenoviral vectors. In in vitro experiments, skin fibroblasts infected with adenovirus vector encoding BMP-2 (AdBMP-2) released substantial levels of BMP-2 proteins into culture media, and those infected with adenovirus vector encoding Runx2 (AdRunx2) produced its protein. Transduction of BMP-2 or Runx2, respectively, increased alkaline phosphatase (ALP) activity and induced expression of mRNAs of ALP, osteocalcin, and osterix in skin fibroblasts. In in vivo experiments, we investigated the bone induction activity by transplantation of a complex composed of carrier [poly-D,L-lactic-co-glycolic acid/gelatin sponge (PGS)] and skin fibroblasts (PGS/SF complex). Transplantation of PGS/SF complexes composed of skin fibroblasts transduced with AdBMP-2-induced ectopic bone formation when transplanted into the subfascia of back muscle, unlike those infected with AdRunx2. Transplantation of PGS/SF complexes composed of skin fibroblasts transduced with AdBMP-2 into craniotomy defects induced bone formation from 2 weeks after transplantation, and almost all PGS was replaced by newly synthesized bone at 6 weeks. To investigate the fate of the transplanted cells, we transplanted skin fibroblasts isolated from green fluorescence protein transgenic mice into craniotomy defects. Transplantation of these skin fibroblasts transfected with AdBMP-2 generated green fluorescence protein-positive osteoblasts and osteocytes, indicating that the transplanted skin fibroblasts differentiated into osteoblastic lineage cells during bone repair. In contrast, transplantation of PGS/SF complexes composed of skin fibroblasts transduced with AdRunx2 induced a few ALP-positive cells at 1 week after transplantation, but their number decreased depending on time after transplantation. In addition, transplantation of these complexes was insufficient to induce bone repair. Taken together, our results suggest that skin fibroblasts expressing BMP-2 are more suitable for cell-mediated therapy of bone repair than those expressing Runx2.

Adenoviridae↗
PubMed2000

Survey of Spirometra erinaceieuropaei in frogs in Taiwan and its experimental infection in cats.

Eighteen of 56 (32.1%) wild Rana limnocharis from central and south Taiwan were found to contain plerocercoids of Spirometra erinaceieuropaei. This is the first report of S. erinaceieuropaei infections in frogs in Taiwan, with the plerocercoids being recovered from the thigh and back muscles or under the skin. Other species of frogs examined, including nine wild R. latouchii, one wild Buergeria robustus and 110 cultured R. rugulosa were free of infection. The plerocercoids were orally inoculated into four cats; three of which were each given a single plerocercoid and one a dose of three plerocercoids. Daily faecal examination showed that two cats started shedding eggs of S. erinaceieuropaei on day 8 postinfection (PI) and the other two on day 10 PI. The highest eggs per gram and eggs per day for a single worm was found to be 428,000 and 14,416,000 respectively. Only the cat inoculated with three plerocercoids shed proglottids in its faeces during the 2 month observation period.

Animals↗
PubMed2005

Altered responsiveness of serotonin receptor subtypes following long-term cannabinoid treatment.

This study examined the effects of long-term cannabinoid administration on the responsivity of 5-HT1A and 5-HT2A receptors, which have been implicated in depression. Animals received 12 d administration of the potent cannabinoid receptor agonist HU-210 (100 microg/kg), following which they were monitored on their behavioural, physiological and hormonal responses to a single challenge of a 5-HT1A and 5-HT2A receptor agonist, 8-OH-DPAT (0.3 mg/kg) and DOI (1 mg/kg) respectively. Chronic HU-210 treatment lead to a significant enhancement of DOI-induced wet-dog shakes, but a reduction of DOI-induced back muscle contractions. DOI-induced corticosterone release was unaffected by HU-210 treatment. The hyperthermic response to DOI appeared to be potentiated by long-term HU-210 treatment, as 50% of these subjects died from an apparent serotonin syndrome with core temperatures exceeding 43 degrees C. The 8-OH-DPAT-induced hypothermic response and elevation of corticosterone were both significantly attenuated by long- term HU-210 treatment. These data imply that chronic cannabinoid treatment may up-regulate 5-HT2A receptor activity while concurrently down-regulating 5-HT1A receptor activity, a finding similar to that sometimes observed in depression. This may partially explain the association between excessive cannabis consumption and the induction of affective disease.

Animals↗
PubMed2002

A comparison of the osteoinductive potential of two calcium phosphate ceramics implanted intramuscularly in goats.

The osteoinductive potential, or bone induction potency, of two calcium phosphate ceramics was evaluated after intramuscular implantation in goats. The ceramics were comprised of hydroxyapatite (HA) and biphasic calcium phosphate (BCP), the later of which contained a 85/15 mixture of hydroxyapatite and tricalcium phosphate (TCP). Both ceramics had a similar macroporosity of around 55% and a pore distribution between 100 and 800 microm. Besides the difference in chemistry, BCP was also microporous and hence had a different surface microstructure. After implantation in the back muscles of four goats for 12 weeks, all 8 BCP samples (7x7x7 mm(3)) showed the presence of bone formation in the macropores (1+/-1%), while no bone was found in any of the HA samples. The used BCP can therefore be characterized as an osteoinductive material. Having the ability to induce bone formation in soft tissues, the BCP presented herein may be a useful biomaterial for bone repair when combined with cultured osteogenic cells, growth factors or both.

Journal Article↗
PubMed2004

Influence of octacalcium phosphate coating on osteoinductive properties of biomaterials.

In this study, we investigated the influence of octacalcium phosphate (OCP) coating on osteoinductive behaviour of the biomaterials. Porous titanium alloy (Ti6Al4V), hydroxyapatite (HA), biphasic calcium phosphate (BCP) and polyethylene glyco terephtalate/polybuthylene terephtalate (PEGT-PBT) copolymer, all uncoated and coated with biomimetically produced OCP, were implanted in back muscles of 10 goats for 6 and 12 weeks. Uncoated Ti6Al4Vand HA did not show any bone formation after intramuscular implantation. All OCP coated implants, except PEGT-PBT, did induce bone in the soft tissue. The reason for the non-inductive behaviour of the copolymer is probably its softness, that makes it impossible to maintain its porous shape after implantation. Both uncoated and OCP coated BCP induced bone. However, the amount of animals in which the bone was induced was higher in the coated BCP implants in comparison to the uncoated ones. Osteoinductive potential of biomaterials is influenced by various material characteristics, such as chemical composition, crystallinity, macro- and microstructure. OCP coating has a positive effect on osteoinductivity of the biomaterials. The combination of the advantages of biomimetic coating method above traditional methods, and a good osteoinductivity of OCP coating that is produced by using this method, opens new possibilities for designing more advanced orthopaedic implants.

Alloys↗
PubMed1992

Levels of complement receptor type one (CR1, CD35) on erythrocytes, circulating immune complexes and complement C3 split products C3d and C3c are not changed by short-term physical exercise or training.

The effect of heavy short-term physical exercise on the levels of complement receptor type one (CR1, CD35) on erythrocytes, the concentrations of circulating immune complexes (IC), and the complement C3 split products C3c and C3d were examined in young healthy males. Fourteen untrained volunteers underwent a 60-min bicycle exercise test at 75% of maximal oxygen uptake (VO2max). Six of the volunteers were exercised twice with an interval of at least one month. Before the second bicycle test they received oral indomethacin. With an interval of at least 1 week, 6 also went through a 60-min back-muscle exercise at up to 30% of VO2max. Blood samples were collected before and during the last few minutes of exercise as well as 2 h and 24 h afterwards. The same parameters were examined once in 29 highly trained racing cyclists. There were no consistent or significant exercise-induced changes in the levels of erythrocyte CR1, circulating IC, C3c nor C3d as measured by an enzyme-linked immunosorbent assay, polyethylene glycol precipitation complement consumption method, and by intermediate gel rocket immunoelectrophoresis, respectively. Neither did these parameters differ from controls in the highly trained group. The results indicate that CR1 on erythrocytes, circulating immune complexes and complement cleavage products C3c and C3d in healthy subjects remain unaffected by short-term heavy physical activity and training.

Adult↗
PubMed1996

Exercise performance in elite male and female sailors.

UNLABELLED: In order to evaluate the physiological profile of elite competitive sailors, and to determine if sailors revealed any seasonal variation in their exercise capacity over a 9 month period, results from female sailors (n = 6), and male sailors ("hikers" n = 8 and "non-hikers" n = 7) were compared with male physical education students (n = 8). Maximal oxygen uptake rate (VO2max) determined on treadmill did not differ between male sailors and control subjects (61.4 +/- 2.0 vs 64.9 +/- 1.4 ml O2/min.kg, mean +/- SE) and did not change with time in elite sailors (p > 0.05). Isometric endurance for abdominal and back muscles was similar for all groups. The isometric muscle endurance in a hiking bench was markedly greater in "hikers" [time: 218 sec (91-426) mean, range] compared to control subjects [time: 98 sec (48-188)], male "non-hikers", and female sailors (p < 0.05). Hiking endurance in "hikers" did not change over the 9 month observation period. Furthermore, dynamic arm performance ("all-out" in 60 sec) was higher in "hikers" compared to all other groups. IN CONCLUSION: Elite sailors who perform hiking activity ("hikers") show an enhanced performance in a functional arm test and higher endurance in a hiking-bench compared to "non-hiking" elite sailors and a control group matched for age, weight and fitness. Furthermore sailors did not show any seasonal variation in their VO2max or isometric endurance over a 9 month period.

Adult↗
PubMedDate not supplied

[Induction of sarcoma by resorbable osteosynthesis material in the rat. A preliminary report].

In an experiment testing the resorption of Poly-l-lactate in the back muscles of Cara rats a foreign body sarcoma occurred in two rats. 20 months after implantation of a body of high molecular weight poly-l-lactate a malignant fibrous histiocytoma developed in one rat. A soft tissue tumor, which was classified according to the immune-histiochemical analysis as a neurogenic sarcoma, developed 23 months after the implantation of a body of injection-casted poly-l-lactate of high molecular weight in a second rat.

Animals↗
PubMed1980

[Modified "faden operation" (author's transl)].

The findings in reviews of faden operations confirm that the procedure will often lead to adhesion of the back muscle surface to the sclera and muscular necrosis or fibrosis. Between 1978 and 1979 a modified faden operation was performed on 136 cases at the Krefeld Eye Clinic. Initial clinical observations seem to indicate that this variation has all the advantages of the faden operation without the risk of extensive adhesion and muscular damage.

Humans↗
PubMedDate not supplied

Biomechanically and electromyographically assessed load on the spine in self-paced and force-paced lifting work.

The purpose of this study was to measure dose of spinal load when different pacing methods were applied to lifting work and to develop methodology for such measurements. The compressive load on the spine computed by a dynamic biomechanical model and the electromyographic activity of back muscles were used for describing the spinal load. Five men and five women worked in a laboratory on two days lifting a box up and down for 30 min on both days, on one day force-paced (4 lifts/min), and on the other self-paced in random order. The weight of the box was rated by the subjects to be acceptable for the work done. The lift rate of our female subjects was higher and that of the male subjects lower in self-paced than in force-paced work. There were no significant differences in peak lumbosacral compressions nor in the amplitude distributions of electromyography between the two pacing methods. The biomechanically-calculated compressive forces on the spine were lower (about 2.7 kN for the men and 2.3 kN for women) than the biomechanical recommendations for safe lifting, but the EMG activity showed quite high peaks so that for 1% of work time the activity was on women above 60% and on men above 40% of the activity during maximum isometric voluntary test contraction.

Adult↗
PubMed2003

Efficacy of dynamic lumbar stabilization exercise in lumbar microdiscectomy.

OBJECTIVE: The aim of this study was to determine the efficacy of dynamic lumbar stabilization exercises in patients with lumbar microdiscectomy. DESIGN: A prospective, randomized, controlled study. SUBJECTS: Forty-two patients who were diagnosed as having lumbar disc herniation and had been operated on using the microdiscectomy method were divided randomly into 3 groups. METHODS: Dynamic lumbar stabilization exercises were set for the first group and a home exercise programme for the second. The third group given no exercises was considered as a control group. All patients were examined twice, once before the exercise programme and once 8 weeks later. RESULTS: Improvement in the first group was highly significant after the treatment (p < 0.0001). The second group improved significantly more in some parameters (pain, functional disability, lumbar Schober, progressive isoinertial lifting evaluation (neck), trunk endurance (flexion-extension)) than did the third group. The third group of patients showed some improvement in fingertip-floor distance, functional disability, modified lumbar Schober and left rotation in 8 weeks, but there were no significant improvements in the other parameters. CONCLUSION: Dynamic lumbar stabilization exercises are an efficient and useful technique in the rehabilitation of patients who have undergone microdiscectomy. They relieve pain, improve functional parameters and strengthen trunk, abdominal and low back muscles.

Adult↗