Weitere experimentelle Studien zur Anaphylaxiefrage

Ohne Zusammenfassung     

A new animal model for bone atrophic nonunion: Fixation by external fixator

A new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well‐defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone. Eighty adult Sprague‐Dawley rats received an osteotomy of the left femur, stabilized with an external fixator. In half of the animals, the periosteum proximal and distal to the osteotomy was destroyed by cauterization and the adjacent bone marrow was removed (nonunion group). At 2 and 8 weeks after surgery, radiological, biomechanical, histological, and histomorphometrical analyses showed a typical physiological healing in the control group, while the nonunion group was characterized by resorption of the bone ends with some callus formation distant to the osteotomy. At both time points, the callus was composed of significantly less bone and significantly more connective tissue (p < 0.001). In addition, the torsional strength of the osteotomized femur was significantly less in the nonunion group than in the control group, which was comparable to that of the intact femur (p < 0.001). In conclusion, the present model allows the induction of an atrophic nonunion without the need of a critical size defect. It is reproducible, provides standardized biomechanical conditions, and allows minimized interaction of the implant with the healing zone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res     

Development of high-affinity choline transport sites in rat forebrain: a quantitative autoradiography study with [3H]hemicholinium-3.

The development of cholinergic terminals in rat brain has been quantitatively analyzed by [3H]hemicholinium-3 autoradiography. [3H]Hemicholinium-3 binds to high affinity choline transport sites, a specific marker for cholinergic neurons. In neonatal animals, kinetic and pharmacologic binding characteristics and regional distribution of [3H]hemicholinium-3 sites are consistent with specific cholinergic localization, as in the adult. The distribution of cholinergic terminals is described in the adult rat brain and during development, including heterogeneity of binding within several regions such as the striatum, nucleus accumbens, olfactory tubercle, cortex, and hippocampus. Early development and maturation vary greatly between brain regions. At embryonic day E18 and day 0, specific binding density is high only in the medial habenula. Development occurs primarily during the postnatal period in most brain regions examined. Many brain regions exhibit a lull in development between days 5 and 10, although the rate of development is highly region specific. Specific binding increases 2-12-fold between day 5 and adult animals, with adult density being achieved anywhere from day 15 to after day 21. The ontogeny of [3H]hemicholinium-3 binding sites generally occurs in a rostral to caudal direction. In the striatal body the characteristic lateral to medial gradient of binding site density is apparent by day 5, and development is more rapid in the lateral striatum. Patches of dense [3H]hemicholinium-3 binding coincident with acetylcholinesterase are observed on day 5 in the caudal striatum. The various patterns of cholinergic terminal development suggest that factors regulating cholinergic development are regional and complex.     

Arthrolysis of the elbow in posttraumatic contracture

Intra- and periarticular fractures about the elbow joint are treated with open reduction and internal fixation. This allows early functional after-treatment. Nevertheless, the range of motion remains more or less unsatisfactory. In these cases open arthrolysis provides a considerable improvement in joint function. We therefore recommend this operation when the hardware is removed about 9 months after the accident. The reasons for post-traumatic contracture of the elbow could be intrinsic such as interposed fragments, intra-articular adhesions, incongruity of the articular surfaces--or extrinsic--like contractures of the capsule and ligaments, adhesions of different layers, ectopic bone formations. In most cases a combination of both can be found. Important conditions for successful arthrolysis are mostly intact joint surfaces, failure of all conservative efforts to improve the arc of motion, a motivated patient who understands clearly the risks and benefits that could reasonably be expected by the operative procedure and rehabilitation and, last but not least, a skilled, experienced surgeon. The choice of the approach depends on the main location of the post-traumatic changes and on previous incisions. Osteotomy of the radial epicondyle gives a much better view of the joint and should be performed whenever necessary. The exact course of the operation may not be standardized. The main point is to remove scarred adhesions and bony irregularities. An individually modified rehabilitation program is as important as the operative procedure itself to achieve the best results possible. In general, the exercises should not cause pain. In the first few days plaster casts in flexion and extension are used. Physiotherapy is supported by CPM machines as early as possible. Patients must be prepared with the help of drugs and the application of ice bags. Even after months improvement of motion can be obtained. In a retrospective follow-up study, 125 out of 168 patients with arthrolysis of the elbow joint were reviewed. Most patients sustained a fracture of the distal humerus. In 77%, the results were graded as very good, good or satisfactory, i.e., the average relative improvement amounted to at least 40% according to the criteria of W. Blauth. Patients with very severe (preoperative ROM 0-30 degrees) and severe (preoperative ROM 30-60 degrees) contractures profited more (relative improvement 60%) than the others (relative improvement 45%). Overall, the average arc of total motion increased 49 degrees; the relative improvement of motion increased by 58%.     

Migration of a subdural-peritoneal shunt into the interhemispheric space

Summary A unique case is reported with retrograde (intracranial) migration of a subdural-peritoneal one-piece shunt and coiling of the tube into the interhemispheric fissure. The cause and the mechanism of this unusual complication are discussed.Dedicated to Prof. Dr. Dr. h. c. K. J. Zülch on occasion of his 70th birthday.     

The adhesion molecule L1 (CD171) promotes melanoma progression

The adhesion molecule L1 is expressed in primary melanomas and cutaneous metastases in contrast to melanocytic nevi and melanocytes, and is significantly associated with metastatic spread. Recent studies have demonstrated that in carcinomas L1 expression is associated with sustained activation of the extracellular signal-regulated kinase (ERK) pathway and upregulation of ERK-dependent, motility- and invasion-associated gene products including alphavbeta3 integrin. The objective of this study was to further investigate the role of the adhesion molecule L1 in melanoma progression, and to evaluate whether targeting the L1 adhesion molecule would have therapeutic effects against invasive melanoma growth. Using human melanoma cells from different stages of progression in monolayer and organotypic human skin culture mimicking the pathophysiological environment of cutaneous melanoma, we found that (1) L1 expression mostly correlates with melanoma progression and alphavbeta3 integrin expression, (2) overexpression of L1 in early radial growth phase melanoma cells promotes conversion from radial to vertical growth phase melanoma without upregulation of alphavbeta3 integrin expression, and (3) suppression of L1 function significantly reduces migration and invasion of melanoma cells, but does not completely block invasive melanoma growth. Altogether, L1 plays a critical role in melanoma invasion and progression and offers therapeutic potential in combination with conventional anticancer agents.     

Schlaf und seine St?rungen im Alter

Restorative sleep is an important factor for preservation of health and quality of life. Sleep quality is associated with age, i.e., sleep disorders occur more frequently particularly after the age of 75?years. Furthermore, sleep shows an association with female gender, inactivity, dissatisfaction with social life, depressive symptoms, pain, intake of sedatives, genetic predisposition, and increased morbidity and mortality in the elderly. Strategies for improving sleep should include (1) effective treatment of organic diseases and mental disorders, (2) elimination of social life factors that impair sleep quality, (3) light therapy and other nonpharmacological treatment options for longer periods, and (4) short-term use of sleep medication as required. For the latter, it should be kept in mind that lower doses are needed in the elderly.