Reactive changes in dorsal roots and dorsal root ganglia after C7 dorsal rhizotomy and ventral root avulsion/replantation in rabbits.

Current surgical treatment of spinal root injuries aims at reconnecting ventral roots to the spinal cord while severed dorsal roots are generally left untreated. Reactive changes in dorsal root ganglia (DRGs) and in injured dorsal roots after such complex lesions have not been analysed in detail. We studied dorsal root remnants and lesioned DRGs 6 months after C7 dorsal rhizotomy, ventral root avulsion and immediate ventral root replantation in adult rabbits. Replanted ventral roots were fixed to the spinal cord with fibrin glue only or with glue containing ciliary neurotrophic factor and/or brain-derived neurotrophic factor. Varying degrees of degeneration were observed in the deafferented dorsal spinal cord in all experimental groups. In cases with well-preserved morphology, small myelinated axons extended into central tissue protrusions at the dorsal root entry zone, suggesting sprouting of spinal neuron processes into the central dorsal root remnant. In lesioned DRGs, the density of neurons and myelinated axons was not significantly altered, but a slight decrease in the relative frequency of large neurons and an increase of small myelinated axons was noted (significant for axons). Unexpectedly, differences in the degree of these changes were found between control and neurotrophic factor-treated animals. Central axons of DRG neurons formed dorsal root stumps of considerable length which were attached to fibrous tissue surrounding the replanted ventral root. In cases where gaps were apparent in dorsal root sheaths, a subgroup of dorsal root axons entered this fibrous tissue. Continuity of sensory axons with the spinal cord was never observed. Some axons coursed ventrally in the direction of the spinal nerve. Although the animal model does not fully represent the situation in human plexus injuries, the present findings provide a basis for devising further experimental approaches in the treatment of combined motor/sensory root lesions.

Effects of root replantation and neurotrophic factor treatment on long-term motoneuron survival and axonal regeneration after C7 spinal root avulsion.

In order to determine the effect of nerve root replantation on motoneuron survival and regeneration, we have avulsed and replanted C7 ventral rootlets in adult rabbits under various conditions. Intraspinal alterations and exact positions of ventrolateral replantations were studied in each animal, and the effects of BDNF and/or CNTF administration during replantation investigated in different experimental groups. Six months after lesion, about 70% of motoneurons were lost on the lesioned sides in the C7 segment, without significant differences between groups. Retrograde fluorescent tracing and histological analysis documented that many axons had regrown through the original ventral exit zones or had exited the spinal cord at the lateral replantation site. However, many laterally exiting axons had not grown out directly from the ventral horn through the lateral white matter but had elongated vertically before leaving the spinal cord. The mean axonal diameter was significantly higher in regenerated axons that had exited through the original ventral exit zones in comparison with axons which had grown out laterally. Application of BDNF and/or CNTF did not show any effects on the pathways of regeneration into the replanted root. The results indicate that motoneuron survival cannot be significantly improved by a single dose of neurotrophic factors applied to a ventrolateral replantation site. However, a significant number of myelinating axons are found in replanted roots, and regeneration may be more efficient when outgrowth through the original ventral exit zone is supported.

Engineered adipose tissue supplied by functional microvessels.

A volume-persistent culture of adipose tissue under in vivo conditions can be achieved only by early vascularization after cell transplantation. Cotransplantation of autologous preadipocytes with endothelial cells may enable the early formation of a capillary network. Investigations were performed in vivo in a specially adapted chorioallantoic membrane (CAM) model. Fertilized White Leghorn eggs were incubated and opened on day 3 of incubation and human dermal microvascular endothelial cell (HDMVEC) spheroids and preadipocytes were transferred in a fibrin matrix to the CAM. On day 7 after incubation the composites were explanted and immunohistologically investigated. Numerous vessels consisting of HDMVECs could be detected and the lumena of these vessels were perfused by chick erythrocytes. These results show the formation of a capillary network consisting of transplanted HDMVECs. The microcirculation of chick erythrocytes in vessels consisting of human endothelial cells proves the continuity of a newly formed capillary system to the host vessel system. The experiments demonstrate the first patent connection of tissue-engineered microvessels in adipose tissue to a host vessel system without applying exogenous angiogenic growth factors or transient transfection. The cotransplantation of endothelial cell spheroids with angiogenic mesenchymal cells may lead to the engineering of complex three-dimensional implants.

The effect of sevoflurane on implicit memory: a double-blind, randomised study.

Forty-eight gynaecological patients were randomly allocated to three groups (target end-tidal sevoflurane concentration 1.2, 1.5 or 2%), and into subgroups for positive or neutral suggestion. Anaesthesia was induced by inhalation of sevoflurane in oxygen. When the target concentration was achieved, the bispectral index, computed from a bi-frontal electroencephalogram, was noted. One of two eight-word lists was then played to prime implicit memory, followed by a positive or neutral suggestion. After surgery, each patient tried to identify 24 words obscured by background noise. Priming increased the likelihood of identifying words in the 1.2% group only, i.e. there was evidence of implicit memory in this group. There was no evidence of a therapeutic effect of positive suggestion (p = 0.3), but the power of this part of the study was low. The bispectral index did not achieve statistical significance as an indicator of susceptibility to priming.

Comparison of performance in materials-based occupation, imagery-based occupation, and rote exercise in nursing home residents.

Materials-based occupation, imagery-based occupation, and rote exercise have been examined individually by several researchers. The present study compares all three approaches with one another (i.e., kicking a balloon, imagining kicking a balloon, and a control rote exercise) in nursing home residents. The dependent variable was the number of exercise repetitions. The subjects were 12 women and 3 men between 56 and 93 years of age residing in two nursing homes. All subjects experienced the three approaches but in different orders. One-way analysis of variance for related measures indicated a significant difference among conditions (p = .004). The Tukey procedure (Stevens, 1986) determined that the materials-based occupation condition elicited significantly more repetitions than the other two conditions. The difference between the imagery-based occupation and rote exercise was not statistically significant. These findings support our profession's historical emphasis on the use of physical materials to enhance performance.

Serological evidence of herpesvirus infection in captive Asian elephants (Elephas maximus).

In mid 1988 a 3-yr-old Asian elephant (Elephas maximus) from a circus in Switzerland died following generalized manifestation of a herpesvirus infection. In an effort to determine prevalence of infection with the herpesvirus, and due to lack of a corresponding virus isolate, it was decided to evaluate contact animals and elephants from a second herd for antibody to bovine herpesvirus 1 (BHV1) and bovine herpesvirus 2 (BHV2). Of 15 sera tested four displayed low neutralizing antibody titers to BHV2. None of the sera neutralized BHV1. However, as evidenced by protein A-mediated immunoprecipitation of metabolically radio-labeled virus-infected and mock-infected cell antigens, followed by separation of precipitation products in SDS-polyacrylamide gels, the 15 sera precipitated multiple antigens from both viruses. Similar results were obtained when using BHV4 antigens. The extent of reaction was most distinct with respect to BHV2 antigens, less prominent with BHV1 antigens, and least with BHV4 antigens. The respective protein patterns, although less marked, matched well with those obtained with bovine reference sera. Additional evaluation of sera from six elephants from two zoos in the Federal Republic of Germany gave essentially identical results. It was concluded that at least one herpesvirus, immunologically related to BHV2, may be widely distributed among captive Asian elephants, and that this virus apparently does not cause overt disease in the majority of animals.

[Realtime sonography of intrascrotal space-occupying lesions]. / Real-time-Sonographie intraskrotaler Raumforderungen.

In 848 examinations of the testes in 317 patients, including 253 follow-up and/or multiple follow-up examinations and 36 unilateral testicle examinations (e.g., orchidectomy, aplasia or nondescent) it was shown that sonography is a diagnostic method which is on the one hand capable of clearly differentiating cystic from solid space-occupying processes, and on the other hand also offers certain possibilities for evaluating the status of solid findings. Histologic identification of malignant tumors was only achieved with teratomas. The differential diagnostic problem was in differentiating scrotal tumors from focal orchitis, chronic epididymitis, testicular torsion and contusion, and in differentiation between paratesticular neoplasms and epididymitides. The testicular findings included testicular neoplasms, cicatrization and cysts of the tunic, sequelae of trauma, orchitis, cryptorchism, hypoplasia, aplasia, and testicular cysts. Paratesticular findings included hydroceles, spermatoceles, varicoceles, paratesticular neoplasms, epididymitides, paratesticular scars, and thickening of the testicular coat.