[Allografted olfactory mucosa gliacytes repair Wistar rats' sciatic nerve long defect].

OBJECTIVE: To investigate whether or not allografted olfactory mucosa gliacytes could repair peripheral nerve injure. METHODS: Olfactory mucosa gliacytes had been cultured in vitro for 2 weeks, then purified and condensed for later transplantation.Sixty adult female Wistar rats were randomized into 2 groups of 30 rats each, A (control) and B (test). Rats' left sciatic nerves were excised 25 mm long axons and retained epineurium lumen anastomosed to proximal ends. Culture mediums, and olfactory mucosa gliacytes were transplanted into epineurium lumen of A and B groups respectively. At 3 months postoperatively, the regenerations of injured sciatic nerves were evaluated by methods of macroscopy, photomicroscopy, transmission electron microscopy, retro-marked fluorescence red, the condensation of glial fibre acid protein (GFAP) and nerve growth factors (NF) assayed by immunofluorescence, and the concentration of myelin basic protein (MBP) and neurofilament protein (NF) assayed by enzyme linked immunosorbent assay. RESULTS: The regenerations of injured sciatic nerves were superior in B group to in A group; the transportation distance of retro-marked fluorescence red were longer in B group than in A group (P < 0.01). The condensations of GFAP and NGF were more dense in B group than in A group. The concentrations of MBP and NF were more high in B group than in A group (P < 0.01). The function scores of injured limbs were superior in B group to in A group (P < 0.01). The quantifications of nerve fibers and myelin fibers of injured sciatic nerve were larger in B group than in A group (P < 0.01). CONCLUSION: Allografted olfactory mucosa gliacytes could repair injured nerve defect.

Biomechanical study of a hat type cervical intervertebral fusion cage.

The purpose of this study was to evaluate the biomechanical effect of a hat type cervical intervertebral fusion cage (HCIFC). In this in vitro biomechanical study, 48 goat cervical spines (C2-5) were tested in flexion, extension, axial rotation, and lateral bending with a nondestructive stiffness method using a nonconstrained testing apparatus, and three-dimensional displacement was measured. Autologous iliac bone and cervical spine intervertebral fusion cage were implanted according to manufacturers' information after complete discectomy (C3-4). Eight spines in each of the following groups were tested: intact, autologous iliac bone graft, Harms cage, SynCage C, carbon cage, and HCIFC. The mean apparent stiffness values were calculated from the corresponding load-displacement curves. Additionally, cage volume and volume-related stiffness were determined. The stiffness of the SynCage C was statistically greatest in all directions. After implantation of the HCIFC, flexion stiffness increased compared with that of the intact motion segment. There was no significant difference in stiffness between the HCIFC and carbon cage. The stiffness of the HCIFC was statistically higher than that of the Harms cage in axial rotation and significantly lower in flexion, extension, and lateral bending. Volume-related stiffness of all cages was higher than that of iliac bone graft. The Harms cage was highest in volume-related stiffness in all directions. The HCIFC can provide enough primary stability for cervical intervertebral fusion.

[In vivo experimental study of hat type cervical intervertebral fusion cage].

OBJECTIVE: To compare the characteristics of interbody fusion achieved using hat type cervical intervertebral fusion cage (HCIFC) with those of an autologous tricortical iliac crest graft, Harms cage and Carbon cage in a goat cervical spine model. METHODS: Thirty-two goats underwent C(3, 4) discectomy and fusion in which the following were used: Group 1, autologous tricortical iliac crest bone graft (8 goats); Group 2, Harms cage filled with autologous iliac crest graft (8 goats); Group 3, Carbon cage filled with autologous iliac bone (8 goats); Group 4, HCIFC filled with autologous iliac graft (8 goats). Radiography was performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the goats were killed and fusion sites were harvested. Biomechanical testing was performed in flexion, extension, axial rotation, and lateral bending to determine the stiffness and range of motion. All cervical fusion specimens underwent histomorphological analysis. RESULTS: One week after operation, the DSH, IVA and LA of HCIFC and Carbon cage were statistically greater than those of autologous iliac bone graft and Harms cage. Significantly higher values for disc space height, intervertebral angle and lordosis angle were shown in cage-treated goats than in those that received bone graft over a 12-week period. The stiffness of Harms cage in axial rotation and later bending were statistically greater than that of other groups. Radiographic and histomorphologic evaluation showed better fusion results in cage groups than in autologous bone group. CONCLUSIONS: HCIFC can provide a good intervertebral distractability and enough biomechanical stability for cervical fusion.

Changes with age and the effect of recombinant human BMP-2 on proteoglycan and collagen gene expression in rabbit anulus fibrosus cells.

In order to compare the difference between young and old intervertebral disc cells and their responsiveness to recombinant human bone morphogenetic protein-2 (rhBMP-2), disc cells were isolated from the anulus fibrosus (AF) and transition zones of lumbar discs from eight old and eight young New Zealand white rabbits. Compared with the cells from the young rabbits, cells from old rabbits respond less to rhBMP-2 treatment with respect to sulfated-glycosaminoglycan (sGAG) synthesis and aggrecan gene expression. But in collagen I and collagen II gene expressions, there are no significant differences between the old and the young. When comparing sGAG content, aggrecan, and collagen II gene expression of the old AF cells after rhBMP-2 treatment with that of the young AF cells without rhBMP-2 treatment, the old AF cells with rhBMP-2 treatment have a greater capacity to synthesize sGAG bound in the cells and to release sGAG in the media, as well as to express aggrecan and collagen II gene. It can be concluded that old AF cells after rhBMP-2 treatment have a greater capacity to synthesize sGAG and express aggrecan and collagen II as compared to young AF cells without rhBMP-2 treatment. Thus rhBMP-2 can reverse the decline in the anabolic capacity of the disc cells with ageing. So it seems that rhBMP-2 has potential for use as an agent to retard a key component of disc degeneration and loss of disc matrix.

DNA degradation in nuclei of muscle cells followed by ischemic injury in a rabbit amputation model.

This study evaluated DNA degradation in nuclei of muscle cells during ischemia in a rabbit limb amputation model. Seven New Zealand rabbits were used. The left rear limb of the animal was amputated. The quadriceps femoris muscle was biopsied, as well as the rabbit carotid arteries. Half of the tissue samples were preserved at a cold temperature (2-4 degrees C), and the other half were kept at room temperature (25 degrees C, global ischemia). Immediately and 4, 8, 12, 16, and 24 h after amputation, muscle tissue samples were stained with the Feulgen reaction and analyzed by an image-analysis system to detect DNA contents in muscle cell nuclei. Samples from carotid arteries were examined with a transmission electron microscope. The results showed that the DNA content in muscle cell nuclei was slightly decreased at 4 and 8 h of global ischemia. At 12 h after global ischemia, the DNA content was found to be significantly decreased (80.03% of baseline). The DNA content dropped to 53.93% of baseline at 16 h of global ischemia. However, in the muscle that was preserved at cold temperature, the DNA contents were only slightly changed along with the ischemia time at 24 h. The DNA changes were confirmed by transmission electron microscopic observations. The present findings could provide evidence for the study of revascularization of ischemic muscle.

Longitudinal intrafascicular electrodes in collection and analysis of sensory signals of the peripheral nerve in a feline model.

The purpose of this study was to evaluate the value of utilizing longitudinal intrafascicular electrodes (LIFEs) in collecting and analyzing sensory signals from the peripheral nerve. The longitudinal intrafascicular electrodes were made of 25-microm Teflon-insulated Pt/Ir wire and implanted into the fascicle of the superficial peroneal nerves in a feline model. The sensory signals at rest status and induced with various stimulations were recorded. The action potential area, frequency, coefficient of variation (CV) of the peak, and functional spectrum were then analyzed by the MF Lab version 3.01 software package. The results showed that the sensory nerve action potentials (SNAPs) were 0-2 spikes per second at rest state; the count was increased when stimulation was administered. SNAPs were 16-24 spikes per second when scraping stimulation was applied. The pulse intervals and the waveform remained consistent. SNAPs burst and were clustered when stress stimulation was given. The comparison of area, frequency, and CV of the peak showed statistically significant differences between these parameters receiving different stimulations. The functional spectrum analysis showed that the frequency of action potential increased when the stress stimulation was applied. In conclusion, LIFEs can sensitively collect sensory signals and provide a good interface to analyze sensory information from peripheral fasciculi. These data provide useful information for further study of control of electronic prostheses.

Clinical detection and movement recognition of neuro signals.

Neuro signal has many more advantages than myoelectricity in providing information for prosthesis control, and can be an ideal source for developing new prosthesis. In this work, by implanting intrafascicular electrode clinically in the amputee's upper extremity, collective signals from fascicules of three main nerves (radial nerve, ulnar nerve and medium nerve) were successfully detected with sufficient fidelity and without infection. Initial analysis of features under different actions was performed and movement recognition of detected samples was attempted. Singular value decomposition features (SVD) extracted from wavelet coefficients were used as inputs for neural network classifier to predict amputee's movement intentions. The whole training rate was up to 80.94% and the test rate was 56.87% without over-training. This result gives inspiring prospect that collective signals from fascicules of the three main nerves are feasible sources for controlling prosthesis. Ways for improving accuracy in developing prosthesis controlled by neuro signals are discussed in the end.

Synthesis of osteogenic growth peptide and its synergetic effect with granulocyte colony stimulating factor.

Osteogenic growth peptide (OGP) has been synthesized through Fmoc solid phase synthesis procedure. The purity of synthetic OGP (sOGP) is over 98.6% identified by HPLC, the amino acid sequence and electro-spray mass spectroscopy are consistent with theoretical values. The synergetic effect of sOGP with recombinant human granulocyte-colony stimulating factor (rhG-CSF) on the hematopoiesis was investigated in normal mice. To assess the synergy of sOGP with rhG-CSF, two schemes were designed. In one scheme rhG-CSF was used at the last 8 days of a 13-day treatment with sOGP, while in the other one both cytokines were given concurrently for 10 days [sOGP, 0.5 nmol/day (mouse); rhG-CSF, 2 microg/day (mouse)]. Both schemes showed that sOGP remarkably synergized with rhG-CSF on increment of white blood cell number and lymphocyte number in peripheral blood without any change of red blood cell and platelet counts. Quantitative differential analysis of bone marrow and histological examination of the spleen and sternum showed that sOGP plus rhG-CSF did not cause abnormal hyperplasia, so sOGP is a very hopeful new drug to improve the effectiveness of clinical used rhG-CSF.

[Experimental study of biocompatibility of LIFEs in peripheral fascicles].

OBJECTIVE: To study the biocompatibility of longitudinally implanted intrafascicular electrodes (LIFEs) in a rabbit sciatic nerve model. And to discuss the possibility of peripheral fascicular signals as a new signal source to control an electronic prosthetic hand. METHODS: LIFEs were implanted chronically into sciatic peripheral fascicles of rabbits as recording and stimulating electrodes. Motor-evoked potentials (MEP) and cortical somatosensory-evoked potentials (CSEP) were recorded by using a transcranial stimulation system (TCS) over six-month period to observe the change of the signals recorded. At the end of the experiments, the fascicles at the electrodes implanted site were anatomized for histological examination under light microscope and transmission electron microscope. In human test, LIFEs were implanted into radial nerve, ulnar nerve and medial nerve of an amputee volunteer. Signals were detected when the volunteer was asked to do different movements of his missing hand, and the signals recorded by LIFEs were used to control an electronic prosthetic hand. RESULTS: The difference of onset latency (OL) of MEP and CSEP recorded at different time has remarkable statistical significance (one way ANOVA, P < 0.001). After multiple comparisons, onset latency (OL) of MEP and CSEP had no obvious change during 1 month, but significantly increased in the later time, and then became stable after 3 months after implantation. The difference of the interpeak amplitudes (IPAs) of MEP recorded at different time has remarkable statistical significance (one way ANOVA, P < 0.001). The interpeak amplitudes (IPAs) of MEP had no distinct change during 1 month, but significantly decreased over the next period, and then became stable after 3 months. Though the interpeak amplitudes (IPAs) of CSEP decreased slowly over six-month period of the study, the difference has no statistic significance (one way ANOVA, P > 0.05). At the end of experiment, histological examination indicated that a typical foreign body reaction developed and electrodes caused a mild damage to fascicles. But inflammatory cells and neuroma were not seen around the electrodes. Signals recorded by LIFEs planted in proximal radial, ulnar and median nerve of the amputated arm were different when the amputee volunteer was ordered to do some different movements with his mind. Some signals could be used to control the seven-freedom electronic prosthetic hand. CONCLUSIONS: Longitudinally implanted intrafascicular electrodes (LIFEs) have excellent biocompatibility with peripheral fascicles. They can be implanted chronically into fascicles and record signals. Furthermore, LIFEs can record physiological signals of peripheral fasciculi when hand moves, and these signals could be used to control an electronic prosthetic hand through further research.

[Primary clinical study on self-setting calcium phosphate cement in bone defect repair of extremities].

OBJECTIVE: To investigate the clinical application of self-setting calcium phosphate cement (CPC) in bone defect repair of extremities. METHODS: From May 1998 to January 2000, 32 cases of bone defect, in 36 sites, were repaired and reviewed, aged from 4 to 59 years old (24.7 years old on average), with bone defect 2 to 125 cm2 in size (13.1 cm2 on average). The causes of the bone defect were fracture, bone cyst, iliac bone harvesting, fibrous dysplasia, enchondroma and bone tuberculosis, which involved femur, iliac, tibia, humerus, phalanx, fibula, calcaneus, talus and acetabulum. All of the cases were followed up for 1 to 23 months, 15.3 months on average, before radiographic examination. RESULTS: All operations were successful and no general response was observed in all of the cases. X-ray examination showed an integrity interface between CPC and bone. And CT showed no gap existed. There was no increase of serum calcium and phosphate levels. CONCLUSION: CPC is applicable in the low- or non-weight-bearing site of the extremities.

Synthetic Osteogenic Growth Peptide Stimulates Osteoblast Osteogenic Activity and Enhances Fracture Healing in Rabbits.

sOGP was synthesized by standard solid phase method, with the purity of 99.2% shown by HPLC and CE. Its amino acid sequence and MS were consistent with theoretical values. In New Zealand white rabbits, sOGP could promote the for mation of new bone and up-regulate the serum level of ALP and BGP as observed by means of biochemical analysis, X-ray, bone mineral density, callus tissue histological analysis and biomechanical tests, demonstrating that sOGP might play a significant role in the tibia fracture healing. Particularly the bone density at 4 weeks and the amounts of trabecular bone in the callus at 2 and 4 weeks of the sOGP-treated group were significantly different from those of control group (P<0.05). Effects of sOGP in different medium in vitro has been studied. sOGP could accelerate osteogenic cell proliferation in 1%BSA-10%NCS-MEM in a dose dependent manner, with a peak at 10(-11) mol/L. But interestingly, this prolife ration activity was not observed in 10%NCS-MEM or 4%BSA-serum free MEM. It suggests that sOGP's osteogenic cell proliferation effects may depend on the involvement of BSA and some regulatory molecules in serum.