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111.
An in vivo study was carried out to determine if capacitive coupled electrical stimulation increased the rate of recovery of strength of regenerate bone produced as a result of lengthening by the Ilizarov technique. Thirty-four adult male beagles underwent a right tibial mid-diaphyseal corticotomy, followed by a 5-day delay, and then 21 days of lengthening (1 mm/day). At the start of the post-distraction period (day 27), stimulation (3-6.3 V peak to peak, 5-10 mA root-mean-square at 60 kHz) was applied for 28 days to one group. The nonstimulated group (n = 17) underwent a 28-day period with no stimulation. From each group, four tibiae were prepared for histology; both ends of the remaining bones were embedded in polymethylmethacrylate and tested in torsion (internal rotation at 4.7 degrees/sec) until failure. Statistically significant changes included a 37% lower maximum torque capacity and a 40% decrease in strain energy to failure in the stimulated group compared with the nonstimulated group. The findings are supported by measured trends to a lower modulus of rigidity (37% decrease) and a smaller percentage of active osteoid perimeter (20% decrease) for the stimulated group. The experimental data suggest that when this dose of capacitive coupled electrical stimulation is applied to the regenerating bone created during distraction osteogenesis, it delays the recovery of bone strength compared with an untreated control. 相似文献
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RK Nath WC Parks SE Mackinnon DA Hunter H Markham PM Weeks 《Canadian Metallurgical Quarterly》1994,29(7):855-862
The deposition of collagen in fetal skin wounds has been shown in several animal models. The authors used a radiolabeled RNA antisense probe, complementary to the mRNA for the alpha-1 chain of human procollagen type I, to assess regulation of this collagen species in fetal and adult rabbit wounds. Dorsal skin wounds were placed on fetal and maternal animals at the beginning of the third trimester, and were harvested 3, 5, and 7 days later. In situ RNA/RNA hybridization was performed on suitable specimens, and morphometric analysis was carried out with a computerized LECO image analyzer. Fetal wounds exhibited an inflow of mesenchymal cells that produced collagen type I at levels higher than the surrounding tissue; this activity was highest on days 3 and 5 after wounding. Adult wounds had increased fibroblast presence by day 7, producing collagen type I at levels higher than those of adjacent unwounded tissue. Morphometric analysis of the signal produced by in situ hybridization and of the number of cells producing the signal in a given field showed that fetal wounds appear to produce collagen type I by an increase in the number of cells in the area of the wound--not by induction of the gene for procollagen type I. In contrast, adult wounds had both fibroblast migration and induction of procollagen type I mRNA synthesis. These findings imply multilevel regulation of collagen production in the adult and posttranslational regulation in the fetus. 相似文献
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PM Rossini F Tecchio V Pizzella D Lupoi E Cassetta P Pasqualetti GL Romani A Orlacchio 《Canadian Metallurgical Quarterly》1998,782(1-2):153-166
The topography of primary sensory cortical hand area following a monohemispheric lesion (sudden = stroke; progressive = neoplasm) was investigated in relationship with clinical recovery of sensorimotor deficits. Twenty seven patients with monohemispheric lesions were studied in a clinically stabilized condition. Functional informations from magnetoencephalography (MEG) were integrated with anatomical data from magnetic resonance imaging (MRI). MEG localizations of the neurons firing at early latencies in primary sensory cortex after separate stimulation of median nerve, thumb and little fingers of each hand were carried out. Characteristics of cerebral equivalent current dipoles (ECDs) activated by each contralateral stimulation, the 'hand extension' (i.e., the distance in millimetres between ECDs of first and fifth digits), as well as interhemispheric differences of the tested parameters were investigated. Finally, ECDs' locations were integrated with MRI. Lesions involving cortical (C) or subcortical (s.c.) areas receiving sensory input from the hand were often combined to increase interhemispheric asymmetry of the tested parameters (22% for C and 49% for s.c. lesions). This might be due to an activation of neuronal districts which in the affected hemisphere (AH) differ from those normally activated in the unaffected hemisphere (UH) and in the control population. Moreover, the 'hand extension' was enlarged on the AH--more frequently after a SC lesion--mainly due to a medial shift of the little finger ECD, combined to a tendency of both finger ECDs to shift frontally. After a C lesion, responses from the AH were often stronger than normal. Spatial reorganizations were also seen in the UH (7% of C and 14% of SC lesions). 'Hand extension' in the UH was selectively enlarged for the P30m only when combined with a similar enlargement in the AH. Significant interhemispheric asymmetries due to neuronal reorganization in the AH were associated with worse clinical outcomes compared to patients without asymmetries. 相似文献
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Consultants with experience of GP intrapartum care believe it is safe for the low-risk woman. However, GPs are perceived as lacking enthusiasm and as having varying degrees of obstetric expertise. Consultants feel that women themselves are not requesting more intrapartum care from GPs. 相似文献
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The paper presents the results of examination of 110 alcoholic patients who have committed criminal actions and were recognized as irresponsible at forensic examination. It was established that wide spectrum of mental disorders were present in such cases--from superacute psychotic states (15 patients) and acute disorders (49) to chronic psychoses (33) and encephalopathy (13). According to clinical manifestations mental disorders correspond in such cases to reactions of exogenic type. In contrast to general medical departments where patients with alcoholic delirium prevail, the studied sample of patients had primarily psychoses with hallucinative-delirious and delirious disorders. Disorders of personality manifested as typical alcoholic, asthenoneurotic, psychopathic-like, residual-psychotic, psychoorganic changes and partial dementia (19 cases). 相似文献
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OBJECTIVES: We sought to characterize the growth of the reconstructed aortic arch after the Norwood operation (NO). BACKGROUND: The first stage of surgical palliation of hypoplastic left heart syndrome (HLHS), the NO, includes augmentation of the aortic arch with homograft. Growth characteristics of the reconstructed aortic arch, which is comprised of both native aortic tissue and homograft, have not been characterized. METHODS: Retrospectively, we examined the serial echocardiograms of 50 patients with HLHS who underwent NO to determine the diameter of the reconstructed transverse arch. Measurements were taken immediately after NO and at two other points (1 to 11 years of age). In addition, the autopsy specimens of 10 other patients with HLHS who underwent NO were examined to determine the contribution of native aortic tissue to the overall size of the reconstructed arch at the time of death (12 to 34 months). RESULTS: The diameter of the transverse aorta increased after NO in all subjects. Its rate of growth paralleled that seen in the normal population, though the reconstructed arch had a significantly larger diameter throughout childhood. Examination of autopsy specimens demonstrated a mean increase in circumference of the native aortic tissue of 0.67 cm (p value <0.01), whereas there was no significant change in homograft circumference. CONCLUSIONS: After reconstruction of the aortic arch in HLHS, the diameter of the arch continues to increase throughout childhood, and this increase is due to growth of the native aortic tissue. 相似文献