Predegenerated nerve allografts versus fresh nerve allografts in nerve repair

This study reevaluated the possibility of using predegenerated nerves as donor nerve allografts for nerve repair and compared the results of functional recovery to those obtained after standard, fresh nerve allograft repair. Twenty donor rats underwent a ligature/ section of the left sciatic nerve 4 weeks before nerve graft harvesting. Forty recipient rats underwent severing of the left sciatic nerve leaving a 15-mm gap between the nerve stumps. Graft repair was undertaken using either the predegenerated left sciatic nerve of the 20 donor rats (predegenerated group, 20 recipient rats) or the normal right sciatic nerve of the 20 donor rats (fresh group, 20 recipient rats). Recovery of function was assessed by gait analysis, electrophysiologic testing and histologic studies. Walking tracks measurements at 2 and 3 months, electromyography parameters at 2 and 3 months, peroperative nerve conduction velocity and nerve action potential amplitude measurements at 3 months, as well as assessments of myelinated nerve fiber density and surface of myelination showed that fresh and predegenerated nerve grafts induced a comparable return of function although there was some trend in higher electrophysiologic values in the predegenerated group. The only slight but significant difference was a larger mean nerve fiber diameter in the nerve segment distal to a predegenerated nerve graft compared to a fresh nerve graft. Although our study does not show a dramatic long-term advantage for predegenerated nerve grafts compared to fresh nerve grafts, their use as prosthetic material is encouraging.     

Distal nerve entrapment following nerve repair

Failure of nerve repair or poor functional outcome after reconstruction can be influenced by various causes. Besides improper microsurgical technique, fascicular malalignment and unphysiologic tension, we found in our clinical series that a subclinical nerve compression distal to the repair site can seriously impair regeneration. We concluded that the injured nerve, whether from trauma or microsurgical intervention, could be more susceptible to distal entrapment in the regenerative stage because of its disturbed microcirculation, swelling and the increase of regenerating axons followed by increased nerve volume. In two cases we found the regenerating nerve entrapped at pre-existing anatomical sites of narrowing resulting in impaired functional recovery. In both cases the surgical therapy was decompression of the distal entrapped nerve and this was followed by continued regeneration. Thorough clinical and electrophysiologic follow-up is necessary to detect such adverse compression effects and to distinguish between the various causes of failed regeneration. Under certain circumstances primary preventive decompression may be beneficial if performed at the time of nerve coaptation.     

Current trends and issues in adaptation-level theory.

"Adaptation levels appear as neutral or indifferent zones in bipolar responses… . Adaptation levels are revealed in all forms of behavior whether they are sensory, motor, or cognitive verbal in nature… . We have found that the weighted log mean definition of AL [Adaptation Level] is the best approximation to the neutral or indifferent region for sensory magnitudes." Studies indicating current trends that bear on fundamental issues in AL theory are considered under the following headings: Anchoring Effects of Subliminal Stimuli; Residual Effects of Anchors in Memory and Recall; Series Effects with an Absolute, Extraexperimentally Anchored Language; Neutral Zones in Unexpected Places; Assimilation and Contrast in Sensory and Social-judgmental Processes; The Methodological Importance for Social Psychology of Studies Leading to Functional Relations Between Variables; and An Adaptation-level for Reinforcement and Performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Current local anesthetics in segmental nerve blocks

The evolution of central segmental blockades was studied in 133 patients by using epidural and spinal anesthesias. The efficiencies of 2% Ultracaine (Hoechst) and 2% Lidocaine (Egis) solutions used for epidural anesthesia and 5% Ultracaine (Hoechst) and 0.75% Bupivacaine (Astra) hyperbaric solutions were evaluated. Central segmental blockade induced by Ultracaine was found to be similar to Lidocaine and Bupivacaine in clinical parameters. At epidural blockade, the latent period was identical for the two agents and the duration of analgesia caused by Ultracaine was 20 minutes longer than that with Lidocaine, the consumption of the former being 20% less. At spinal anesthesia, there were no great differences in the depth and duration of conduction block, but with 5% Ultracaine, the analgesic zone was large (13.2 +/- 1.0 and 15.1 +/- 0.6 segments, p < 0.05). No differences were found in the magnitude of hemodynamic changes both with various anesthetics and different types of segmental blockades. The findings make it possible to regard Ultracaine as an drug that has some advantage over Lidocaine for prolonged epidural anesthesia and similar to the latter in pharmacological characteristics. Ultracaine may be regarded as alternative to Bupivacaine for spinal anesthesia.     

A tissue-engineered conduit for peripheral nerve repair

BACKGROUND: Peripheral nerve repair using autograft material has several shortcomings, including donor site morbidity, inadequate return of function, and aberrant regeneration. Recently, peripheral nerve research has focused on the generation of synthetic nerve guidance conduits that might overcome these phenomena to improve regeneration. In our laboratory, we use the unique chemical and physical properties of synthetic polymers in conjunction with the biological properties of Schwann cells to create a superior prosthesis for the repair of multiply branched peripheral nerves, such as the facial nerve. OBJECTIVES: To create a polymeric facial nerve analog approximating the fascicular architecture of the extratemporal facial nerve, to introduce a population of Schwann cells into the analog, and to implant the prosthesis into an animal model for assessment of regeneration. RESULTS: Tubes of poly-L-lactic acid (molecular weight, 100000) or polylactic-co-glycolic acid copolymer were formed using a dip-molding technique. They were created containing 1, 2, 4, or 5 sublumina, or "fascicular analogs." Populations of Schwann cells were isolated, expanded in culture, and plated onto these polymer films, where they demonstrated excellent adherence to the polymer surfaces. Regeneration was demonstrated through several constructs. CONCLUSIONS: A tubular nerve guidance conduit possessing the macroarchitecture of a polyfascicular peripheral nerve was created. The establishment of resident Schwann cells onto poly-L-lactic acid and polylactic-co-glycolic acid surfaces was demonstrated, and the feasibility of in vivo regeneration through the conduit was shown. It is hypothesized that these tissue-engineered devices, composed of widely used biocompatible, biodegradable polymer materials and adherent Schwann cells, will be useful in promoting both more robust and more precisely directed peripheral nerve regeneration.     

Current issues of mathematical modeling and advancement in radiology

A 22-year-old woman was found in bed unresponsive and hypotensive after an apparent overdose. Subsequent workup in the emergency department identified a ruptured ectopic pregnancy and extensive hemoperitoneum. A significant delay occurred when emergency physicians excluded the possibility of pregnancy because of the patient's normal menstrual history. A qualitative serum or urine pregnancy test is recommended in all women of child-bearing age who present with poisoning or drug overdose.     

Current status and prominent issues in sport psychology interventions

The prospect of human psycho-behavioral change has fueled the development and growth of applied sport psychology and psychological intervention with athletes. The purpose of this review is to examine the current status of sport psychology interventions and identify issues related to psychological intervention in sport. The development of sport psychology in North America is overviewed and issues arising from the emergence of applied sport psychology are identified. Sport psychology intervention research is reviewed and it is concluded that the effectiveness of sport psychology interventions is supported in the literature. Problems in intervention research are identified and future directions for sport psychology are suggested. These suggestions include a science-practice integration, the use of idiographic assessment methods, the identification and control of moderator variables, and the contextualization of interventions within the unique environment of sport.     

Current issues in the management of chronic obstructive pulmonary diseases

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, especially among smokers. Many guidelines that have recently been issued emphasize that COPD is not inaccessible to therapeutic measures: although few interventions are capable of affecting its natural history (i.e. smoking cessation and, in patients with severe resting hypoxaemia, oxygen therapy), several others have a demonstrated effect on symptoms and, thereby, quality of life. The effects of inhaled corticosteroids, and alpha 1-antitrypsin replacement therapy in emphysema due to alpha 1-antitrypsin deficiency are currently being studied. When there is a marked increase in mucus production, chest physiotherapy using controlled expiration and directed cough may be useful. Inhaled bronchodilators are frequently effective on dyspnoea, anticholinergic agents being more suitable for continuous symptoms. Rehabilitation, which includes education and psychosocial care, chest physiotherapy, nutritional care and exercise training, also improves quality of life. When there is persistent severe alveolar hypoventilation despite oxygen therapy, long-term mechanical ventilation may be considered. Surgical options in the treatment of emphysema include resection of giant bullae and lung volume reduction surgery. Lung transplantation should be proposed only in patients with end-stage disease, the difficulty here being to define what 'end-stage' means. Finally, all preventive and some therapeutic interventions are likely to be more effective early in the course of the disease. Thus, efforts should be made to detect airways obstruction early in subjects at risk, such as smokers.     

Current issues in the diagnosis and therapy of diabetic nephropathy

Significant increases in serum levels of IgE have often been observed in allogeneic bone marrow transplantation patients and have generally been thought to be diagnostic of graft-versus-host disease (GVHD), rather than an agent involved in the pathogenesis of the disease. Experimental murine GVHD models have also indicated associations of hyper-IgE activity, yet the role of IgE in GVHD pathogenesis has never been tested directly. In the current study, we have tried to address this issue by using recently developed peptide analog antagonists for the interaction of IgE with the Fc epsilon RI receptor, which is necessary for triggering mast cells and other cell types when cross-linked by antigens. A synthetic cyclized 13-amino acid peptide was previously designed from the modeled C-C' loop region of the Fc epsilon RI alpha-chain and was found to act as a competitive inhibitor of IgE-Fc epsilon RI alpha binding. The peptide was generated in two forms, a cyclic L-(L-IgEtide) and retro D-amino acid composition (rDIgEtide), the latter to increase resistance to protease degradation for in vivo applications. These two inhibitor peptides were then used to test the hypothesis that IgE could be involved in the pathogenesis of acute GVHD, in the B10.D2-->DBA/2 (900 cGy) strain combination, with GVHD directed to minor histocompatibility antigens. Both peptides demonstrated significant inhibition of the development of lethal GVHD, supporting the involvement of IgE at some level of disease pathogenesis.     

The preparation of advanced practice nurses. Current issues

The changes and challenges that nurses face today are preparation for the future. Incorporating ongoing refinements in practice directed toward improving patient outcomes and maintaining the willingness to be visionary in the preparation of nurses for the advanced practice nurse role bode well for the future. This article addresses the history of, need for, and educational preparation of advanced practice nursing.     

Brain-stimulation reward: Current issues and future prospects.

Discusses (a) the neuroanatomical systems subserving brain-stimulation reward and (b) the functions such systems have in controlling and modifying an animal's behavioral repertoire. It is suggested that future research should focus on the role of ideation in learning. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social-skills interventions with adolescents. Current issues and procedures

During adolescence, the interpersonal interactions and behaviors necessary for successful social functioning become increasingly complex. In recent years, social-skills training with adolescents has made a variety of advances beyond basic skill acquisition toward techniques designed to promote generalization and maintenance of an effective interpersonal repertoire. This article reviews relevant empirical literature for current issues and procedures in social-skills training with adolescents, including use of social-skills interventions for a variety of adolescent populations and problems, use of innovative and promising intervention procedures, and issues regarding generalization and social validity of intervention procedures.     

Results of cable graft technique in repair of large nerve trunk lesions

Cable grafting was reintroduced in the beginning of the 1980's as a modified method for repair of large polyfascicular nerves without group arrangement such as trunks and cords of the brachial plexus, sciatic nerve and its divisions, or the other main nerve trunks. We used this method in 25 patients with brachial plexus injury and 29 patients with injuries to the sciatic nerve. Results were analyzed according to the individual nerve elements and were available for 32 elements of the brachial plexus and for 19 tibial and 19 peroneal divisions of the sciatic nerve. We defined useful functional recovery according to the priorities in repair of the brachial plexus and sciatic nerve with lower limits M3 for relevant muscles and functions and S2 for sensory function. Results were especially favourable for the brachial plexus with a total rate of recovery 84% and for tibial division with the same total rate of recovery. On the basis of the results obtained we were able to conclude that the results of the modified cable grafting were at least similar to those of interfascicular nerve grafting and that this method could be useful for repair of large polyfascicular nerve trunks. However, the main advantage of this technique is a considerable gain in operative time.     

Peripheral nerve repair in the hand with and without motor sensory differentiation

To investigate the value of motor sensory differentiated nerve repair, we examined a group of 9 patients with motor sensory differentiated nerve repair and a group of 13 patients without motor sensory differentiated nerve repair. The clinical and electroneurographic findings were compared. For the clinical examination, Millesi's scoring system was used. The hand function after motor sensory differentiated median nerve repair was 72% +/- 16% compared with 57% +/- 14% without motor sensory differentiation. The hand function after motor sensory differentiated median and ulnar nerve repair was 53% +/- 12% compared with 43% +/- 24% without motor sensory differentiation. After ulnar nerve repair the achieved values for hand function were high even without motor sensory differentiation. Our results indicate that intraoperative motor sensory differentiation of injured nerves is helpful to reestablish particularly the sensory function in median nerve injuries.