Wolfram Neiss

Summary The ability of the facial motor system to adapt to a new motor function was studied in alert cats after unilateral transection, 180∞ rotation and suture of the zygomatic nerve, or transection and cross-anastomosis of the prox- imal stump of the buccal nerve to the distal stump of the zygomatic nerve. These procedures induced reinner- vation of the orbicularis

Facial and hypoglossal nerves were resected unilaterally in a total of 108 rats. Rats were divided into two groups; one group received standard food pellets (placebo), the other received food pellets containing the Ca(2+)-blocking agent nimodipine. The expression of glial fibrillary acidic protein was examined in paraffin sections of the brainstem using light microscopical immunocytochemistry, and the degree of glial process ensheathment of the surviving neuronal perikarya in the hypoglossal and facial nuclei quantified on electron micrographs. Up to 28 days post-axotomy no differences in glial fibrillary acidic protein-immunoreactivity were observed between placebo and nimodipine-treated animals. By 42-56 days, glial fibrillary acid protein-immunoreactivity was stronger in the nimodipine treated animals and by 112 days, glial fibrillary acid protein-immunoreactive astrocytes occurred only in nimodipine-treated animals. Thin astrocytic processes were seen to ensheath neurons in both...

Immature motility of the ileum may contribute to life-threatening diseases. Little is known about the normal biomechanics of the neonatal ileum in relation to the protein composition of its contractile machinery. We analyzed the tissue architecture, the biomechanics in intact and β-escin-permeabilized preparations, and the protein composition in neonatal (P0) and adult murine ileum. Muscle thickness of the P0 ileum was -50% of the adult ileum and passive compliance was higher. Carbachol- and KCl-elicited contractions were tonic rather than phasic as in the adult. Ca(2+) sensitivity was higher and relaxation rate was slower in β-escin-permeabilized P0 compared with adult ileum. The expression level of β-actin relative to α-actin was higher, and those of total actin, myosin, myosin light chain kinase, the catalytic subunit of myosin phosphatase and telokin were lower compared with the adult. The expression level of MYPT1 was similar, but P0 ileum expressed only the M133; the adult ile...

Microglial activation in response to pathological stimuli is characterized by increased migratory activity and potential cytotoxic action on injured neurons during later stages of neurodegeneration. The initial molecular changes in the CNS favoring neuronofugal migration of microglia remain, however, largely unknown. We report that the extracellular matrix protein tenascin-R (TN-R) present in the intact CNS is antiadhesive for activated microglia, and its downregulation after facial nerve axotomy may account for the loss of motoneuron protection and subsequent neurodegeneration. Studies on the protein expression in the facial and hypoglossal nucleus in rats demonstrate that TN-R is a constituent of the perineuronal net of motoneurons and 7 d after peripheral nerve injury becomes downregulated in the corresponding motor nucleus. This downregulation is reversible under regenerative (nerve suture) conditions and irreversible under degenerative (nerve resection) conditions. In short-ter...

Facial-facial anastomosis (FFA), i.e., suture of transected facial nerve, was performed in adult Wistar rats. For 10-112 d post-operation (DPO), half of the animals received standard food (placebo) and half received food pellets containing 1000 ppm nimodipine, a Ca2+ channel blocker. The time course of mimetic reinnervation between these two groups was compared by counting all retrogradely labeled motoneurons after injection of horseradish peroxidase (HRP) into the whiskerpad. In unoperated animals, injection of HRP labeled 1280 +/- 113 motoneurons. After FFA, this number dropped to zero, and the first HRP-labeled facial motoneurons reappeared in both placebo- and nimodipine-treated animals at 14 DPO. The treatment with nimodipine yielded two beneficial effects. (1) It accelerated axonal sprouting until 28 DPO. Whereas the number of HRP-labeled cells in the placebo group was 171 +/- 9 (mean +/- SD) at 16 DPO, 372 +/- 43 at 21 DPO, and 636 +/- 187 at 28 DPO, the number of sprouted mo...

Image analysis was used to quantify the time course of chromatolysis in regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal nerve suture, or resection of facial and hypoglossal nerves with postoperative survival times of 4 h to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial

Distal humeral fractures are rare, but severe injuries, the treatment of which is often accompanied by serious complications and its outcome strongly depends on the quality of surgical therapy. Non-union is a common entity, compromising clinical results and requiring revision surgery. Osteonecrosis is an underestimated etiologic factor in the development of non-union. The present study aims to display the distribution patterns of the arterial vessels at the distal humerus, to correlate the displayed vessels with local nutrient foramina and to disclose an endangerment of these structures by common osteosynthetic implants. Eight plastinated fresh frozen upper extremities were digitally analyzed regarding the vascular density of the cancellous bone, by calculating the ratio of area comprised by arterial vessels and the area comprised by cancellous bone on sagittal cuts of the distal humerus. Possible differences in the vascular density of the medial epicondylar region, the lateral epicondylar region and a watershed area between the epicondyles and distal to the supracondylar region were investigated. On the basis of 200 macerated humeri, the distribution pattern of cortical nutrient foramina and their anatomic relation to properly applied common distal humerus plates were documented. The data show a significantly higher density of vessels per cancellous bone in the epicondylar regions than in the watershed region (p < 0.000, median 0.148 vs. 0.103). The analysis of the nutrient foramina showed distinct distribution patterns with a single foramen over the medial epicondyle (55 specimens, 27.5 %) and an area of several foramina at the posterior part of the lateral epicondyle (200 of the specimens, 100 %). In almost every specimen, the application of the osteosynthetic implants led to an overlay over the investigated nutrient foramina. Osteonecrosis and non-union are severe complications in the surgical treatment of distal humeral fractures. The biology of the bone, especially the blood supply, has to be respected as much as possible during open procedures, to optimize bony healing. This has to be considered when performing periosteal stripping or applying osteosynthetic plates over the postero-lateral and medial epicondyle. The watershed area of the distal humerus has to be considered as being prone to minor arterial blood supply and thereby non-union is possible, if the arterial vessels coming from the epicondyles are destroyed.

Functional recovery after peripheral nerve injury depends on the amount as well as on the accuracy of reinnervation by regenerative axons. In this study, the rat sciatic nerve was subjected to crush injury or complete transection repaired by either (1) straight nerve suture, (2) crossed nerve suture of tibial and peroneal fascicles, or (3) silicone tubulization leaving a gap of 4 mm. The compound muscle action potentials (CMAP) of gastrocnemius, tibialis anterior and plantar muscles were recorded 90 days post operation to assess functional reinnervation and Fast Blue, Fluoro Gold and DiI were applied to the nerve branches projecting into these muscles to quantify morphological reinnervation. The CMAP amplitude achieved in gastrocnemius, tibialis anterior and plantar muscles was higher after nerve crush (86%, 82%, 65% of control) than after any surgical nerve repair (straight suture: 49%, 53%, 32%; crossed suture: 56%, 50%, 31%; silicone tube: 42%, 44%, 25%). The total number of labeled motoneurons, however, did not significantly differ between groups (control: 1238 +/- 82, crush: 1048 +/- 49, straight suture: 1175 +/- 106, crossed suture: 1085 +/- 84, silicone tube: 1250 +/- 182). The volume occupied by labeled motoneurons within the spinal cord was larger after surgical nerve repair than in crush or normal control animals, and fewer neurons showed abnormal multiple projections after crush (2.5%) or straight suture (2.2%) than following crossed suture (5%) or silicone tube (6%). In conclusion, nerve repair with a silicone tube leaving a short gap does not increase accuracy of reinnervation.

Recovery after peripheral nerve injury depends not only on the amount of reinnervation, but also on its accuracy. The rat sciatic nerve was subjected to an 8 mm long gap lesion repaired either by autograft (AG, n = 6) or tubulization with impermeable silicone tube (SIL, n = 6) or permeable tube of poly-L-lactide-epsilon-caprolactone (PLC, n = 8). Recordings of the compound muscle action potential (CMAP) from gastrocnemius (mGC), tibialis anterior (mTA) and plantar (mPL) muscles were performed 90 days after injury to assess the amount of muscle reinnervation. The CMAP amplitude achieved in mGC, mTA and mPL was similar in after nerve autograft (39%, 42%, 22% of control values) and PLC tube implantation (37%, 36%, 24%) but lower with SIL tube (29%, 30%, 14%). The nerve fascicles projecting into each of these muscles were then transected and retrograde tracers (Fluoro Gold, Fast Blue, DiI) were applied to quantify the percentage of motoneurons with single or multiple branches to different targets. The total number of labeled motoneurons for the three muscles did not differ in autografted rats (1186 +/- 56; mean +/- SEM) with respect to controls (1238 +/- 82), but was reduced with PLC tube (802 +/- 101) and SIL tube (935 +/- 213). The percentage of neurons with multiple projections was lower after autograft and PLC tube (6%) than with SIL tube (10%). Considering the higher CMAP amplitude and lower number of neurons with multiple projections, PLC nerve conduits seem superior to SIL tubes and a suitable alternative to autografts for the repair of long gaps.

We have recently demonstrated that the beta-galactoside-specific lectin galectin-3 is expressed by microglial cells in vitro, but not by normal resting microglia in vivo. In the present study, we have analyzed the expression of galectin-3 by microglia under traumatic conditions in vivo using two experimental rat models which substantially differ in the severity of lesion related to a breakdown of the blood-brain barrier (BBB) and the occurrence of inflammatory processes. These two features are absent after peripheral nerve lesion and present after cerebral ischemia. Here we show that, following facial nerve axotomy under conditions allowing (nerve anastomosis) or not subsequent regeneration (nerve resection), galectin-3 is not expressed by microglia in the corresponding facial nucleus 1-112 days after lesion. Galectin-3 is also absent in microglia at sites of a defective BBB in the normal brain, such as the circumventricular organs. Following experimental ischemia (i.e., permanent occlusion of the middle cerebral artery), in contrast, galectin-3 becomes strongly expressed by activated microglia as early as 48 hours after trauma, as determined by immunohistochemistry and Western blot analysis. Our findings suggest that the expression of galectin-3 by microglia in vivo correlates with the state of microglial activation.

Image analysis of the textural feature entropy of the Nissl substance was used to monitor the time course of chromatolysis in regenerating hypoglossal motoneurons and degenerating facial motoneurons 4-112 days after hypoglossal-facial anastomosis in rats. Changes in the Nissl substance were detected that were not obvious on the basis of subjective judgement of the light-microscopical appearance of the neurons. Chromatolysis started 4 days post operation (dpo) and was not reversed at 112 dpo in both nuclei. The increase of chromatolysis was 14-28 dpo faster in the regenerating hypoglossal neurons than in degenerating facial neurons. Maximal chromatolysis was measured at 56-70 dpo in both nuclei. Afterwards chromatolysis persisted at a significantly higher level in the degenerating facial motoneuron pool. In conclusion, chromatolysis is a very long persisting reaction. In the beginning chromatolysis is faster and greater in regenerating rather than in degenerating neurons. In contrast, passing the maximal reaction, chromatolysis is maintained at a higher level in degenerating motoneurons. Image analysis of textural features is a suitable and reliable tool to monitor the time course of neuronal cell body changes. The presented quantitative method could be applied in any neurobiological study influencing the regeneration or degeneration of motoneurons.

Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dystrophin. Also, denervated and immediately reinnervated muscle fibers showed decreased expression of nNOS. However, muscle fibers reinnervated for 10 weeks revealed a restored physiological expression of nNOS. There were no changes in the expression of endothelial and inducible NOS. As NO is known to induce growth arrest and collapse of neuronal growth cones, downregulation of NOS may contribute to promotion of axonal regeneration by aiding formation of new endplates. NO is upregulated in reinnervated muscle fibers and thus prevents polyneural hyperinnervation by extrajunctional synapses. Furthermore, downregulation of NOS during denervation is compatible with the finding that low levels of NO contribute to apoptosis instead of necrosis in disease states of oxidative stress.

The Ascension PyroCarbon prosthesis has been used in proximal interphalangeal joint osteoarthritis. The dimensions of the intramedullary distal metadiaphyseal canal (isthmus) of the proximal phalanx and the base of the middle phalanx of cadaver fingers were investigated radiographically (n = 304) and macroscopically (n = 152). In up to 30% of the phalanges, the isthmus was smaller than the stem of the smallest proximal component size. The distal component head was always smaller than the middle phalanx base. Insertion and success of the Ascension PyroCarbon prosthesis is strongly dependent on bone morphology. A critical examination of the isthmus in radiographs is recommended in planning. If the isthmus is clearly smaller than the smallest proximal component, insertion of the prosthesis could be inadvisable. A clear mismatch between the distal component and the middle phalanx base should be avoided due to the potential risk for late subsidence and failure of the prosthesis.

Surgical reconstruction of the facial nerve is common clinical practice following destruction of the intracranial facial nerve. Delayed hypoglossal-facial anastomosis (HFA) is the procedure of choice, although the effect of delay on outcome remains unclear. To study the effect of delayed anastomosis on reinnervation, we sutured the proximal stump of a freshly transected hypoglossal nerve of Wistar rats to the distal stump of the ipsilateral facial nerve, which had been transected 7-56 days earlier. Animals that had received HFA without delay served as the control group. Forty days after HFA, horseradish peroxidase (HRP) was injected into the whisker pad; 2 days later, the animals were killed. Reinnervation was assessed by determining the proportion of labeled neuronal cell bodies in the brainstem. The control group had 68% reinnervation of these muscles by hypoglossal neurons and had 32% reinnervation by facial neurons. When the distal facial nerve had been allowed to degenerate for 7 days before HFA, reinnervation of the hypoglossal nerve decreased to 54%, and reinnervation by the facial nerve increased to 46%. However, after a delay of 10-56 days, the hypoglossal fraction increased and stabilized at 77%, and the facial motoneuron fraction decreased to 23%. The presence of new neuromuscular junctions was confirmed by HRP labeling of motor end plates in vivo and by electromyography. We conclude that, under the conditions of hypoglossal-facial crossed nerve suture, the predegeneration of the distal stump of a transected facial nerve enhances the reinnervation of facial muscles by hypoglossal axonal sprouts.

Injection of Fluoro-Gold (FG) into the whiskerpad muscles of rats yields a permanent retrograde labeling of motoneurons in the facial nucleus. Following subsequent resection of 10 mm of the facial nerve, one-third of the facial motoneurons die and the microglia phagocytize the dead FG-labeled neurons, take up FG, and get labeled in vivo. The resulting identification of all FG-labeled cells allows long-term comparative investigations on the behavior of neuronophages. In this study, we used two groups of rats to test whether the quantified expression of five immune-related antigens by neuronophages was related to quantified decline in neuron number (counts after immunostaining for neuron-specific enolase) 3 to 224 days after resection of the facial nerve. Rats of the first group received standard food and those of the second group, pellets containing 1,000 ppm of the calcium channel blocker nimodipine. Image analysis of the number of FG-containing cells and the number and projection area of immunopositive neuronophages in serial sections for each antigen showed that nimodipine significantly attenuated the immunostaining for CR3, MHC class I, and class II antigens (monoclonal antibodies [MAbs] OX-42, OX-18, and OX-6); enhanced the expression of monocyte-macrophage-specific antigen (MAb ED1); and did not change the expression of rat macrophage differentiation antigen (MAb ED2). The altered expressions, however, had no effect on the loss of motoneurons in the lesioned facial nucleus. We conclude that the degree of expression of immune-related antigens by neuronophages has no influence on the delayed neuronal cell death induced by permanent target deprivation.

The immunohistochemical profiles of ubiquitin, heat shock protein 70, alpha-B-crystallin, desmin, vimentin, neural cell adhesion molecule (N-CAM), and tenascin in rat facial muscle were studied after permanent denervation by transection of the facial plexus on one side and compared with findings after immediate reinnervation by hypoglossal-facial nerve anastomosis subsequent to transection on the contralateral side. Levator labii muscle samples were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery. Normal levator labii muscle fibers showed physiological expression of desmin and alpha-B-crystallin. Denervated rat facial muscle displayed distinct up-regulation of ubiquitin, alpha-B-crystallin, N-CAM, and tenascin. While alpha-B-crystallin and N-CAM decreased in long-standing denervation, tenascin had completely disappeared at 6 weeks. Like-wise, reinnervated muscles displayed enhanced expression of ubiquitin, alpha-B-crystallin, N-CAM, tenascin, and, additionally, desmin. Strong expression of desmin and ubiquitin was found up to the 10th week as well as of alpha-B-crystallin, N-CAM, and tenascin up to the 7th week of reinnervation. Afterward, expression of stress proteins, intermediate filaments, and adhesion molecules returned to expression profiles of normal controls, indicating that enhancement of these proteins was restricted to the "atrophic and regenerative" states with a decline to physiological levels after successful reinnervation and restoration of muscle fibers. Furthermore part of regeneration from damage seems to resemble reactivated developmental mechanisms by reappearance of developmentally expressed proteins like desmin, N-CAM, and tenascin.

Functional recovery after facial nerve surgery is poor. Axotomized motoneurons (hyperexcitable upon intracellular current injections, but unable to discharge upon afferent stimulation) outgrow supernumerary branches which are misrouted towards improper muscles. We hypothesized that alterations in the trigeminal input to axotomized electrophysiologically silent facial motoneurons might improve specificity of reinnervation. To test this we compared, in the rat, behavioural, electrophysiological, and morphological parameters after transection and suture of the buccal facial nerve (buccal-buccal anastomosis, BBA) with those after BBA plus excision of the ipsi- or contralateral infraorbital nerve (ION). After BBA, the mystacial vibrissae dropped and remained motionless until 18-21 days post operation (days PO). After BBA plus ipsilateral ION excision, there was no recovery of vibrissae whisking at all. Following BBA plus contralateral ION excision, full restoration of whisking occurred at 7-10 days PO. Electromyography of whiskerpad muscles showed normal waveform and amplitude was also most rapidly restored after BBA plus contralateral ION excision. Neuron counts after retrograde tracing showed that the intact buccal nerve contained axons of the superior (91%) and inferior (9%) buccolabial nerves. After BBA, the superior nerve comprised 56%, the inferior 21%, and 23% of the motoneurons projected within both nerves. After BBA plus ipsilateral ION excision, misdirection worsened and values changed to 48, 39 and 13%, respectively. After BBA plus contralateral ION excision, portions improved to 69, 23 and 8%. We conclude that, by reducing the redundant axon branching, lesion of contralateral ION provides the best conditions for recovery of vibrissae rhythmical whisking after reconstructive surgery on the facial nerve.

This study was designed to determine whether exposure to multimodal early onset stimulation (MEOS) combined with environmental enrichment (EE) after traumatic brain injury (TBI) would improve neurological recovery and to elucidate its morphological correlates. Male Sprague-Dawley rats were subjected to lateral fluid percussion (LFP) brain injury or to sham operation. After LFP, one-third of the animals (injured and sham) were placed under conditions of standard housing (SH), one-third were kept in EE only, and one-third received EE + MEOS. Assessment of neuromotor function 24 h post-injury using a standardized composite neuroscore test revealed an identical pattern of neurological impairment in all animals subjected to LFP. Neuromotor dysfunction in SH animals remained on a similar level throughout the experiment, while improvements were noted in both other groups 7 days post-injury (dpi). On 15 dpi, reversal of neuromotor dysfunction was significantly better in EE + MEOS animals vs. SH- and EE-only groups. In parallel, the comparison of lesion volume in EE + MEOS- vs. EE-only vs. SH rats revealed that animals exposed to EE + MEOS had consistently the lowest values (mm3, mean +/- SD; n = 6 rats in each group) as measured in serial brain sections immunostained for neuron-specific enolase (5.2 +/- 3.4 < or = 5.5 +/- 4.1 < 9.5 +/- 1.9), caspase 3-active/C3A (5.9 +/- 4.0 < or = 6.4 +/- 3.9 < 10.3 +/- 1.8) and glial fibrillary acidic protein (6.0 +/- 3.4 < or = 6.5 +/- 4.3 < 10.7 +/- 1.2). This first report on the effect of EE + MEOS treatment strongly indicates that the combined exposure reduces CNS scar formation and reverses neuromotor deficits after TBI in rats.

In experimental studies on peripheral nerve repair, the possibility to objectively compare original and post-operative innervation is of decisive importance for the selection of the proper nerve-reconstruction strategy. Herewith we report serious drawbacks encountered with the standard method of pre- and post-operative intramuscular injections of widely used retrograde neuronal tracers. Labeling of rat facial motoneurons by injection of Fast-Blue (FB; Group 1), Dil (Group 2), or Fluoro-Gold (FG; Group 3) into the whisker pad muscles was followed by transection and suture of the facial nerve. Two months later, the same rats received Dil (Group 1), FG (Group 2), and FB (Group 3) injections with the same parameters as the pre-operative injections. By quantitative evaluation of single- and double-retrogradely labeled perikarya of facial motoneurons, we tried to estimate the accuracy of re-innervation. Observations through a "UV-filter" (for FB-labeled perikarya) and a "rhodamine-filter" (for Dil-labeled perikarya) in Group 1 revealed an unexpected axotomy-triggered leakage of FB which compromised the counts. After pre-operative Dil labeling, nerve suture, and post-operative FG labeling (Group 2), Dil created an extracellular deposit in the whisker pad. Thus, the uptake of pre-operative tracer by sprouts of re-growing axons compromised counts of retrogradely labeled motoneurons. Employing the "UV-filter" in Group 3 (FG-, FB-, FG+FB-labeled perikarya), the emission of FB obscured that of FG and also compromised cell counts. The use of filter sets constructed ad hoc for detection of FG and FB rendered possible an objective comparison.

Axotomy induces a profound modification of Ca2+ homeostasis in injured neurons which may lead to neuronal death. Remarkably, after axotomy and resection of the hypoglossal nerve, 65-75% of the hypoglossal motoneurons survive in the long term and this suggests some adaptive mechanisms compensating the massive calcium influx. As potential components of this adaptation, we have examined calmodulin and calbindin-D28k by in situ hybridisation and immunohistochemistry in motoneurons of the rat after hypoglossal nerve transection. Neuronal calbindin mRNA and protein content was low in normal state, transiently increased to 200% of the basal expression at 8 days post-operation (dpo), then declined to normal again until 28 dpo. Calmodulin mRNA was highly expressed in normal hypoglossal motoneurons and remained constant after axotomy. Calmodulin protein immunoreactivity, however, was transiently decreased in axotomised motoneurons suggesting post-transcriptional modification. The upregulation of calbindin expression may facilitate the survival of injured motoneurons.

Hypoglossal facial anastomosis (HFA) is a standard surgical technique for restoration of facial movements in cases of intratemporal lesions of the facial nerve. Case reports provide evidence that an affected trigeminal system reduces functional outcome. In order to detect morphological changes in the hypoglossal nucleus responsible for this phenomenon, we used 18 Wistar rats and performed three different surgical combinations. In group 1, six animals received HFA only. In group 2, HFA was combined with resection of the contralateral infraorbital nerve. In group 3, HFA was combined with resection of the ipsilateral infraorbital nerve. Fifty-six days after the operation, horseradish peroxidase (HRP) was injected into the whisker pad. As shown in previous studies using HRP, retrograde-labelled motoneurons occurred in the hypoglossal and facial nuclei. Counts of the labelled motoneurons showed no change in the number of projecting hypoglossal motoneurons in group 2 when compared to HFA only, but a significantly smaller number in group 3 (-35%). Furthermore, the number of projecting facial motoneurons was significantly reduced in group 2 (-85%) and group 3 (-45%). These morphological findings indicate an absent or insufficient functional connection between the contralateral infraorbital nerve and the hypoglossal nucleus, and a strong influence of the infraorbital nerve to the ipsi- and contralateral facial nuclei. Additionally, our study provides morphological evidence that the integrity of the sensory trigeminal system is very important in reconstructive facial nerve surgery.