Assessing unilateral neglect: shortcomings of standard test methods

INTRODUCTION

When investigating the incidence of unilateral neglect in a first-ever stroke population, we found that some patients showed clinical signs of neglect, but managed to pass our tests. The purpose of this paper is to describe the nature of such signs, and analyse why test instruments were insufficiently corresponding to those signs.

METHOD

One hundred and thirty-one consecutive patients with first-ever stroke in a community-based sample were evaluated for the presence of unilateral neglect. We used a test battery consisting of tests for visuo-spatial neglect, personal neglect, and anosognosia. Twenty cases of neglect were discovered by standard methods. We asked our collaborators at the wards to report any behavioural abnormality reminiscent of neglect present in patients who had normal test results. Such patients were evaluated clinically.

RESULTS

Nine cases with neglect-like symptoms were discovered. Our clinical evaluation of the nine patients indicated several possible explanations for their behavioural abnormalities, including motor neglect, neglect for far extrapersonal space, disturbances of proprioception, and spatial disturbances other than neglect.

CONCLUSION

Standard neglect tests do not cover all clinical forms of neglect. It is therefore important not to rely completely on test instruments when diagnosing neglect. More versatile test instruments are desired.

Societal services after traumatic spinal cord injury in Sweden

OBJECTIVE

Societal services after traumatic spinal cord injury in Sweden were investigated, including self-rated levels of satisfaction with the application process and resource allocation.

DESIGN

Survey of an incidence population.

SUBJECTS

Thirty-four persons of a total regional incidence population (n = 48) with traumatic spinal cord injury.

METHODS

Structured interviews using a standardized questionnaire.

RESULTS

About 25 separate services were identified being available for persons with traumatic spinal cord injury. The average number of applications per person was 5 (range 0-11). The most common service was "transportation service". Of the applications, 17% were partially or totally rejected. Most subjects received information about available services from a social worker. For 13 available services at least 1 subject claimed ignorance about its existence.

CONCLUSIONS

In Sweden, significant resources are allocated for allowing independence and financial compensation for individuals with traumatic spinal cord injury. However, this support system sometimes also results in frustration and disappointment. Insufficient information and co-ordination are reported as weaknesses. The persons' efforts to acquire knowledge of how the system works take time which could be better used for rehabilitation and full integration into the community.

High incidence rates of stroke in Orebro, Sweden: Further support for regional incidence differences within Scandinavia

BACKGROUND AND PURPOSE

As a basis for comparison of differences in stroke incidence in Scandinavian countries, a community-based stroke register was established in Orebro in the centre of Sweden.

METHODS

All first-ever cases of stroke were registered during a 12-month period 1999-2000. The study population was 123,503. The WHO definition of stroke was used. Cases were searched inside as well as outside hospital. Multiple overlapping sources and 'hot pursuit' technique were used in the process of case ascertainment.

RESULTS

388 cases of first-ever stroke were found, corresponding to a crude incidence rate of 314 (95% CI, 283-348) per 100,000 per year, 337 (95% CI, 294-386) for females, and 289 (95% CI, 248-336) for males. Adjusted to the European population, the corresponding rates were 254 (95% CI, 227-284) per 100,000 per year, 273 (95% CI, 238-311) for females and 232 (95% CI, 206-261) for males. The overall 28-day case-fatality rate was 19% (95% CI, 15-23). The case-fatality rates for the different subtypes of stroke were as follows: brain infarction, 10%; intracerebral haemorrhage, 20%; subarachnoidal haemorrhage 45%, and undetermined pathological type 56%.

CONCLUSIONS

The present study as well as other studies in northern and middle Scandinavia show significantly higher incidence rates than studies from other regions. The crude incidence rate, reflecting the age distribution of the population, is even higher, indicating a burden to the community that is rather increasing than decreasing.

Expression patterns of neurotrophic factor mRNAs in developing human teeth

Neurotrophic factors regulate survival, differentiation, growth and plasticity in the nervous system. In addition, based on their specific and shifting temporospatial expression patterns, neurotrophic factors have been implicated in morphogenetic events during tooth development in rodents. To determine whether these findings in rodents could be related to humans, we have now studied nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), neurotrophin-4 (NT-4), glial cell-line derived neurotrophic factor (GDNF), and neurturin (NTN) mRNA expression patterns in developing human teeth during gestational weeks 6.5-11. Using in situ hybridization histochemistry, we found distinct and specific patterns of neurotrophin and GDNF mRNA expression in the developing human teeth. NGF mRNA labeling was weak and confined predominantly to the dental papilla. BDNF mRNA labeling was stronger than NGF mRNA and was seen in the mesenchyme located lateral to the dental organ, as well as in epithelial structures (inner dental epithelium and enamel knot). NT-3 mRNA was observed in the dental papilla and in the area of the cervical loop. NT-4 mRNA was expressed in both oral and dental epithelia in all stages studied. GDNF mRNA was found in the dental follicle and at different sites in the inner dental epithelium. Weak NTN mRNA labeling was also found in the developing teeth. Based on these findings, we suggest that neurotrophins, GDNF and NTN might be involved in morphogenetic events during early stages of tooth development in humans. Protein gene product (PGP) 9.5-immunoreactive nerve fibers were observed in the dental follicle by 11 weeks coinciding with the labeling for neurotrophic factor mRNAs in this structure. This suggests that these neurotrophic factors might be involved in the innervation of dental structures. The rich expression of neurotrophic factors in developing dental tissues suggests that developing, or possibly adult, dental tissue might be used as an allograft source of trophic support for diseases of the nervous system.

Predictors of severe stroke: influence of preexisting dementia and cardiac disorders

BACKGROUND AND PURPOSE

There is little research into the impact of prestroke dementia on stroke severity and short-term mortality. We included prestroke dementia, along with other risk factors, to determine independent predictors of stroke severity and early death in a community-based stroke study.

METHODS

All patients (n=377) with a first-ever stroke were evaluated in terms of risk factors. Registration took place over a 12-month period. Stroke severity was evaluated with the National Institutes of Health Stroke Scale. Predictors of severe stroke and early death were analyzed in logistic regression models. The following independent variables were used: age, sex, living alone, arterial hypertension, ischemic heart disease, heart failure, atrial fibrillation, diabetes mellitus, transient ischemic attack, cigarette smoking, peripheral atherosclerosis, and dementia.

RESULTS

Risk factors for stroke were found in 82% of the patients. Heart failure, atrial fibrillation, and dementia were associated with more severe strokes. Dementia, atrial fibrillation, heart failure, and living alone were associated with death within 28 days of the event.

CONCLUSIONS

These results raise the question of whether certain high-risk patients, ie, patients with atrial fibrillation, heart failure, and dementia, can benefit from more aggressive primary and secondary stroke prevention measures.

Neglect and anosognosia after first-ever stroke: incidence and relationship to disability

Neglect and anosognosia are serious consequences of stroke. Authors have found great variations in their incidence and their relationship to disability has been unclear. We studied the incidence of neglect and anosognosia within the scope of a population-based stroke-incidence study, and also evaluated their impact on disability. Four tests of visuo-spatial neglect, four tests of personal neglect, and an anosognosia questionnaire were used. Sixty-two patients (23%) of the study group had visuo-spatial neglect according to our definition, 21 patients (8%) had personal neglect, and 48 (17%) showed signs of anosognosia. Using a multiple logistic regression model, we found that both neglect and anosognosia influenced disability. To ascertain the true incidence of neglect and anosognosia after stroke, it is necessary to use a community-based study design, where cases treated outside the hospital are included. Some of the variability found in previous incidence studies is likely to be explained by not using such a design.

Constitutive and inflammatory induction of alpha and beta chemokines in human first trimester forebrain astrocytes and neurons

Chemokine effects on leukocyte infiltration into the central nervous system (CNS) are key events in the inflammatory processes of neuroimmunologic and neuroinfectious diseases. Because, chemokines may play important roles in proliferation and differentiation of brain cells and in the initiation and progression of CNS inflammatory disorders, we analyzed constitutive and inflammatory-induced expression of alpha and beta chemokines in human first trimester forebrain cells. Constitutive induction of IL-8, MIP-1alpha, MIP-1beta, MCP-1 and regulated on activation, normal T-cell expressed, and secreted (Rantes) was detected in cryostat sections of embryonic forebrains in an age-dependent manner. Dissociated cell cultures were studied for spontaneous chemokine induction and after stimulation with the trypanosome lymphocyte triggering factor (TLTF), a novel trypanokine secreted by African trypanosomes that triggers a complex of immune responses. LPS and variant surface glycoprotein (VSG) were used as controls. In cultures, unstimulated cells expressed minimal chemokine levels except for Rantes. In response to TLTF and LPS, but not VSG, all chemokines were highly induced at the mRNA and protein levels in a dose- and age-dependent manner. Combined assays (in situ hybridization and immunohistochemistry) revealed that astrocytes and neurons are major sources for chemokines. These results illustrate the ability of resident brain cells to constitutively express chemokine genes, which may suggest an important role for chemokines during brain development. Furthermore, TLTF-induced chemokine expression in astrocytes and neurons indicate the capacity of TLTF to provoke neuroinflammation in the brain, which may have important therapeutic implications for the neurological manifestations of African trypanosomiasis.

Cloning and expression of the human N-methyl-D-aspartate receptor subunit NR3A

Native N-methyl-D-aspartate (NMDA) receptors are heteromeric assemblies of four or five subunits. The NMDA receptor subunits, NR1, NR2A, NR2B, NR2C, and NR2D have been cloned in several species, including man. The NR3A subunit, which in rodents is predominantly expressed during early development, seems to function by reducing the NMDA receptor response. The human homologue to the rat NR3A, however, had not been cloned. In order to study the functions of the human NR3A (hNR3A), we have cloned and sequenced the hNR3A. It was found to share 88% of the DNA sequence with the rat gene, corresponding to a 93% homology at the amino acid level. Based on available data from human genome databases, we localized the gene to chromosome 9. The transcript could be detected by in situ hybridization in human fetal spinal cord and forebrain. Two splice variants of NR3A have been reported in rat brain, the longer of the two containing a 60 bp insert in the intracellular domain. We were unable to detect this 60 bp insert in fetal or adult human brain, suggesting that only the short variant is expressed in humans.

Movement-provoked muscle torque and EMG activity in longstanding motor complete spinal cord injured individuals

Muscle resistance was evaluated by measurement of movement-provoked torque performed during simultaneous thigh muscle EMG recordings in individuals with a motor complete spinal cord injury (SCI). Fifteen men with a motor complete (ASIA grade A or B) cervical injury participated in the study. The activity started at an average of 0.11 seconds after the start of the provoking movement as evidenced by EMG recordings. However, no activity at all was found before the end of the movement provocation for 0.3 seconds in >60% of the test situations, whereas muscle torque was recorded in all cases. Significantly higher resistive muscle torque (p = 0.049) was provoked during extension movement compared with that of flexion. On the contrary, the maximum muscle activity was significantly higher (p = 0.009) during flexion movement compared with that during extension, with no differences between muscle groups. The resistive muscle torque seems to measure the passive viscoelastic component rather then the active spastic component of the movement-provoked muscle resistance in our group of motor complete SCI individuals.

The alpha7 nicotinic receptors in human fetal brain and spinal cord

The alpha7 nicotinic acetylcholine receptor subtype is believed to be involved in the regulation of neuronal growth, differentiation and synapse formation during the development of the human brain. In this study the expression of the alpha7 nicotinic acetylcholine receptor was investigated in human fetal brain and spinal cord of 5-11 weeks gestational age. Both the specific binding of [125I]alpha-bungarotoxin to prenatal brain membranes and the expression of alpha7 mRNA were significantly higher in the pons, medulla oblongata, mesencephalon and spinal cord of 9-11 weeks gestational age compared with cerebellum, cortex and subcortical forebrain. A significant positive correlation between gestational age and the expression of alpha7 mRNA was observed in all brain regions except cortex. A positive correlation was also observed between the gestational age and the [125I]alpha-bungarotoxin binding in the pons, medulla oblongata, mesencephalon, and cerebellum. Consequently, a significant relationship between the alpha7 mRNA levels and the binding sites for [125I]alpha-bungarotoxin was found in the fetal brain. The increasing levels of the alpha7 nicotinic acetylcholine receptor during the first trimester support the important role of nAChRs for the development of the central nervous system.

African trypanosomes activate human fetal brain cells to proliferation and IFN-gamma production

We addressed the host-parasite interplay and the immunopathogenetic events occurring in the central nervous system (CNS) during human African trypanosomiasis. Human first trimester forebrain cells were stimulated with a trypanosome lymphocyte-triggering factor (TLTF) and studied for their immune response as exemplified by cell proliferation and IFN-gamma production. TLTF induced proliferation of human first trimester forebrain cells and IFN-gamma production at the mRNA and protein levels. Astrocytes are the major producers of IFN-gamma in response toTLTE These data illustrated for the first time a direct effect of a parasite factor on human brain cells. TargetingTLTF during the course of the disease may be considered in preventing the deadly neurological complications of human African trypanosomiasis. NeuroReport

Spontaneous axonal regeneration in rodent spinal cord after ischemic injury

Here we present evidence for spontaneous and long-lasting regeneration of CNS axons after spinal cord lesions in adult rats. The length of 200 kD neurofilament (NF)-immunolabeled axons was estimated after photochemically induced ischemic spinal cord lesions using a stereological tool. The total length of all NF-immunolabeled axons within the lesion cavities was increased 6- to 10-fold at 5, 10, and 15 wk post-lesion compared with 1 wk post-surgery. In ultrastructural studies we found the putatively regenerating axons within the lesion to be associated either with oligodendrocytes or Schwann cells, while other fibers were unmyelinated. Immunohistochemistry demonstrated that some of the regenerated fibers were tyrosine hydroxylase- or serotonin-immunoreactive, indicating a central origin. These findings suggest that there is a considerable amount of spontaneous regeneration after spinal cord lesions in rodents and that the fibers remain several months after injury. The findings of tyrosine hydroxylase- and serotonin-immunoreactivity in the axons suggest that descending central fibers contribute to this endogenous repair of ischemic spinal cord injury.

Effects of functional electrical stimulation training for six months on body composition and spasticity in motor complete tetraplegic spinal cord-injured individuals

The effect of functional electrical stimulation (FES) training on body composition, assessed by computed tomography, and the effect of spasticity, assessed by both objective and subjective measures, are evaluated. Fifteen motor-complete spinal-cord-injured men participated in the study. Eight of the 15 subjects undertook FES cycling 3 times weekly for 6 months. Whole body computed tomography scans evaluated changes in body composition. Simultaneous Modified Ashworth Scale and electromyography (EMG) measurements, resistive torque (Kin-Com) and EMG measurements, and self-ratings with Visual Analogue Scale during four consecutive days were used to evaluate changes in spasticity. Lower extremity muscle volume increased by an average of 1300 cm3 (p < 0.001) in the training group compared to the control group, who experienced no change. Otherwise no changes in body composition were seen. Significant correlations (Spearman) were found between individual EMG activity recordings and movement-provoked Modified Ashworth Scale ratings in 26% of the test situations, irrespective of group and time. The objective and subjective evaluation of movement-provoked passive (viscoelastic) and active (spasticity-related) resistance remained unchanged.

Solid human embryonic spinal cord xenografts in acute and chronic spinal cord cavities: a morphological and functional study

While therapeutic spinal cord grafting procedures are of interest in the chronic spinal cord injury stage, previous experimental grafting studies, including human spinal cord tissue, have mainly focused on the acute stage. Therefore, solid human embryonic spinal cord grafts were implanted in acute or chronic spinal cord aspiration cavities of immunodeficient rats to compare the morphological and locomotor outcome to that of lesion alone cases. Locomotor function was assessed using the Basso, Beattie, and Bresnahan open-field locomotor rating scale up to 6 months, while the morphological evaluation of graft survival, growth, and integration was performed at 6 weeks or 6 months after implantation. Graft survival was 94% in both lesion models, while graft growth was enhanced in the chronic compared to the acute cavity group. Human specific Thy-1 and neurofilament immunoreactive fibers were observed up to 7 mm into host white matter, while aminergic fibers were observed up to 1 mm into the grafts. Abundant calcitonin gene-related peptide immunoreactive fibers in the grafts in the absence both of immunoreactive cell bodies and colocalized human-specific neurofilament immunoreactivity, suggested host fiber ingrowth. At 6 months, the grafted cases presented less central canal deformation and lower glial fibrillary acidic protein immunoreactivity at the host cavity border compared to that of the nongrafted cases. The strong compensatory regain of locomotor function after unilateral spinal cord lesions was not affected by the human spinal cord grafts. In conclusion, solid human embryonic spinal cord tissue transplanted to a cavity in the adult injured spinal cord results in beneficial morphological effects in both the acute and chronic spinal cord lesion.

Expression of presenilin-1 and Notch-1 receptor in human embryonic CNS

In vitro studies have shown that the Alzheimer's disease-related presenilin-1 protein can mediate Notch-1 receptor cleavage during signalling. In the present study, we compared the distribution of presenilin-1 and Notch-1 receptor immunoreactivities in human embryonic CNS tissue during the first trimester of development. Our aim was to gain insight into whether these proteins are likely to interact functionally during human fetal brain development. CNS material was obtained from routine abortions, cryosectioned and studied by means of immunohistochemistry with antibodies to presenilin-1 and Notch-1. At very early stages of embryonic development (four to five gestational weeks) intensive presenilin-1 immunoreactivity could be seen predominantly in neurites in the ventral horn of the spinal cord, where it overlapped with 200-kDa neurofilament immunoreactivity. Presenilin-1 immunoreactivity was also seen in neuroblasts of the ventricular zone of the tel- and mesencephalon, as well as of the brainstem. Notch-1 receptor appeared in neuronal and ependymal cells throughout the CNS. Seven- to eight-week CNS tissue showed similar patterns of presenilin-1 and Notch-1 receptor expression in the spinal cord and cerebral cortex as was seen at five weeks. Both proteins were localised in the neuroepithelial cell layer lining the ventricles, as well as in the cortical plate layer, where immunoreactivity was seen in the cell bodies. In addition, presenilin-1 immunoreactivity was seen in thin neurites in the subplate of the developing cortex. At 10 weeks, presenilin-1 immunoreactivity was reduced in the spinal cord. These results show that, although presenilin-1 and Notch-1 receptor are localised to the same differentiating cell populations in the human cerebral cortex, making a direct interaction possible, these proteins are otherwise confined to different neurons or neuronal compartments, suggesting a role for presenilin-1 during early CNS differentiation that does not involve Notch-1 receptor processing. Double staining for presenilin-1 in the endoplasmic reticulum and presenilin-1 in the Golgi showed overlap to some extent in investigated CNS regions, but not in neurites. This suggests that presenilin-1 function during neurogenesis is not exclusively correlated to protein processing within the endoplasmic reticulum and Golgi, but that presenilin-1 may also be involved in other processes, such as axonal and dendritic outgrowth or synaptic formation. In summary, our findings provide supportive evidence that the presenilin-1 protein is involved in the development and maturation of the human fetal CNS. The presence of presenilin-1 immunoreactivity in both the cell bodies and neurites of developing neurons strongly suggests divergent mechanisms of function for presenilin-1 during human brain development. These may include interactions with any of the Notch receptor proteins, as well as Notch-independent mechanisms.

RANTES promotes growth and survival of human first-trimester forebrain astrocytes

We have examined the role of alpha and beta chemokines in the promotion of the ontogenetic development of the brain. RANTES was expressed preferentially in human fetal astrocytes in an age-dependent manner. Astrocytes from 5-week-old brains showed high proliferation and reduced survival, whereas 10-week-old astrocytes exhibited opposite effects. These effects were suppressed by anti-RANTES or anti-RANTES receptor antibodies and were enhanced by recombinant RANTES. RANTES induced tyrosine phosphorylation of several cellular proteins and nuclear translocation of STAT-1 in astrocytes. Interferon-gamma (IFN-gamma) was required for RANTES effects because RANTES induced IFN-gamma and only 10-week-old astrocytes expressed the IFN-gamma receptor. Blocking of IFN-gamma with antibody reversed the effects of RANTES, indicating that cytokine/chemokine networks are critically involved in brain development.

Functional connections are established in the deafferented rat spinal cord by peripherally transplanted human embryonic sensory neurons

Functionally useful repair of the mature spinal cord following injury requires axon growth and the re-establishment of specific synaptic connections. We have shown previously that axons from peripherally grafted human embryonic dorsal root ganglion cells grow for long distances in adult host rat dorsal roots, traverse the interface between the peripheral and central nervous system, and enter the spinal cord to arborize in the dorsal horn. Here we show that these transplants mediate synaptic activity in the host spinal cord. Dorsal root ganglia from human embryonic donors were transplanted in place of native adult rat ganglia. Two to three months after transplantation the recipient rats were examined anatomically and physiologically. Human fibres labelled with a human-specific axon marker were distributed in superficial as well as deep laminae of the recipient rat spinal cord. About 36% of the grafted neurons were double labelled following injections of the fluorescent tracers MiniRuby into the sciatic and Fluoro-Gold into the lower lumbar spinal cord, indicating that some of the grafted neurons had grown processes into the spinal cord as well as towards the denervated peripheral targets. Electrophysiological recordings demonstrated that the transplanted human dorsal roots conducted impulses that evoked postsynaptic activity in dorsal horn neurons and polysynaptic reflexes in ipsilateral ventral roots. The time course of the synaptic activation indicated that the human fibres were non-myelinated or thinly myelinated. Our findings show that growing human sensory nerve fibres which enter the adult deafferentated rat spinal cord become anatomically and physiologically integrated into functional spinal circuits.

Expression of interleukin-6 in human dorsal root ganglion cells

The expression of Interleukin-6 (IL-6) was studied in normal dorsal root ganglia (DRG) of juvenile and foetal humans, using immunohistochemistry and in situ hybridization techniques. There was an expression of IL-6-like immunoreactivity in more than 75% out of neuronal cells in the juvenile ganglia with a peripheral localization, and also an expression in the foetal ganglion cells. There was a co-localization of IL-6 with substance P (SP) and calcitonin gene-related peptide (CGRP) in more than 60% of the DRG cells, respectively. By in situ hybridization 0.9% of the cells in the juvenile ganglia and 1.1% of the cells in the foetal ganglia showed a positive signal for IL-6. In addition, expression of IL-6 was found in juvenile medulla spinalis, preferentially in the white matter.

Lingual BDNF and NT-3 mRNA expression patterns and their relation to innervation in the human tongue: similarities and differences compared with rodents

Brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) mRNAs are expressed in developing and adult rodent tongue and are important for the proper development of lingual gustatory and somatosensory innervation in rodents. Here, we wished to determine whether the findings in rodents apply to humans. By using in situ hybridization histochemistry, distinct, specific, and in some instances overlapping patterns of BDNF and NT-3 mRNA expression were found in the developing and adult human tongue, gustatory papillae, and taste buds. BDNF mRNA was expressed in the superior surface epithelium of the developing fungiform papillae (i.e., developing taste buds), in the epithelium covering the circumvallate papillae, and in the subepithelial mesenchyme. Interestingly, BDNF mRNA was expressed in the lingual epithelium before nerve fibers reached the epithelium, indicating a prespecialization of the gustatory epithelium before the arrival of nerves. In the adult fungiform papillae, BDNF mRNA labeling was found in taste buds and in restricted areas in the non-gustatory lingual epithelium. NT-3 mRNA was found in the developing lingual epithelium and gustatory papillae. NT-3 mRNA labeling was observed in the adult fungiform taste buds, overlapping with BDNF mRNA labeling, in contrast to what was seen in rodents. NT-3 mRNA was additionally found in restricted areas in filiform papillae. Protein gene product 9.5 (PGP) antibodies were used to investigate a possible correlation between lingual innervation and sites of neurotrophin gene activity. Adult human tongue innervation differed from that of rodents, possibly in part due to a different neurotrophin expression pattern in the human tongue. Based on these findings, we suggest that BDNF and NT-3 are important for the initiation and maintenance of the gustatory and somatosensory innervation also in humans. The broader and somewhat overlapping expression patterns of BDNF and NT-3 mRNAs, compared with rodents, suggest additional and possibly somewhat overlapping roles for BDNF and NT-3 in the human tongue and also indicate differences between species. It is important that interspecies differences be taken into consideration.

Ionotropic glutamate receptor expression in human spinal cord during first trimester development

Quantitative receptor autoradiography and immunoblotting were used to study the expression and distribution of AMPA, kainate and NMDA receptors in first trimester human spinal cord obtained from elective abortions ranging from 4 to 11.5 weeks of gestational age. Spinal cord tissue sections were processed for receptor autoradiography with the ligands [3H]AMPA, [3H]kainate and [3H]MK-801 and the optical density was measured separately in a dorsal region (alar plate) and ventral region (basal plate) of the autoradiographs. Binding sites for all three ligands were demonstrated already at 4-5.5 weeks of gestation and increased continuously during the first trimester both in the dorsal and ventral regions. [3H]AMPA binding to both high- and low-affinity sites increased from undetectable levels to about 35 and 400 fmol/mg tissue, respectively, during this period. A temporal difference in the distribution of [3H]AMPA binding sites was observed. The early homogeneous pattern of [3H]AMPA binding in both alar and basal plates had changed to a heterogeneous pattern at 11 weeks of gestation with the highest density of [3H]AMPA binding sites in the superficial layers of the immature dorsal horn. [3H]kainate and [3H]MK-801 binding sites were densely and homogeneously distributed already at 4 weeks, and steadily increased six- and two-fold, respectively, to about 100 fmol/mg tissue at 11.5 weeks of gestation. Immunoreactive bands corresponding to the NMDA receptor subunits NR1, NR2A, NR2B, NR2C and NR2D were demonstrated by immunoblotting at the earliest between 4.5 and 7 weeks and increasing concentrations were seen up to 11 weeks of gestation. These results suggest that AMPA, kainate and NMDA receptors are expressed in the human spinal cord early in embryogenesis.

Spasticity after traumatic spinal cord injury: nature, severity, and location

OBJECTIVE

To assess spasticity in a prevalence population of persons with traumatic spinal cord injury (SCI), and determine the degree of correspondence between self-reported spasticity and investigator-elicited spasticity using the modified Ashworth scale.

DESIGN

Survey of a near total (88%) prevalence population.

SETTING

Outpatient clinic of a university hospital.

PATIENTS

A total of 354 individuals with SCI.

MAIN OUTCOME MEASURES

The survey includes self-reported symptoms, neurologic examination (American Spinal Injury Association [ASIA] classification), physical therapy examination, range of motion (ROM), and complications.

RESULTS

Presence of problematic spasticity was significantly correlated with cervical incomplete (ASIA B-D) injury. Reports of beneficial effects of spasticity were significantly less common in women. Self-reported problematic spasticity was significantly correlated with extensor spasticity. Spasticity was elicitable by movement provocation in 60% of the patients reporting spasticity. Significant correlations were found between elicitable spasticity and limited ROM.

CONCLUSION

Flexion, extension, and abduction movements performed with the patient placed in a standardized supine test position are suitable both for test of ROM and degree of spasticity. Spasticity was not elicitable by movement provocation on physical examination in 40% of the patients who reported spasticity, thus indicating that the patient's self-report is an important complement to the clinical assessment. A significant association between spasticity and contractures (reduced ROM) was seen.

Nerve growth factor-induced stimulation of dorsal root ganglion/spinal cord co-grafts in oculo: enhanced survival and growth of CGRP-immunoreactive sensory neurons

Intraocular co-grafts of rat fetal spinal cord and dorsal root ganglia were used to examine the enhanced survival, growth, and differentiation of sensory neurons by nerve growth factor. E14 lumbar spinal segments were implanted into the anterior eye chamber of capsaicin-pretreated rats. Two weeks later, an E14 dorsal root ganglion was implanted beside the spinal cord graft. Nerve growth factor or vehicle was injected weekly for 4 weeks into the anterior eye chamber. Co-grafts were examined weekly and, at 6 weeks, processed for calcitonin gene-related peptide (CGRP) immunofluorescence. No differences in overall size were determined for the grafts. Co-grafts treated with nerve growth factor contained many more CGRP neurons (19.4 cells/20 microm) that were significantly larger (mean 764 microm2) than neurons from control co-grafts (8.6 cells/20 microm; mean 373 microm2). In co-grafts treated with nerve growth factor, CGRP-immunoreactive fibers were extensive in the dorsal root ganglion, adjacent iris, and spinal cord compared to control co-grafts. A few CGRP-positive motoneurons were observed in the spinal cord, but no differences in number or size of motoneurons were found. The current report demonstrates that spinal cord and dorsal root ganglia can be co-grafted in oculo for long periods of time. Many dorsal root ganglion neurons survive and send peripheral processes into the iris and central processes into the spinal cord under the influence of exogenous nerve growth factor. The intraocular graft paradigm can be of use to further examine the role of neurotrophic factors in regulating or modulating dorsal root ganglion and spinal cord neurons.

In vitro expansion of a multipotent population of human neural progenitor cells

The isolation and expansion of human neural progenitor cells have important potential clinical applications, because these cells may be used as graft material in cell therapies to regenerate tissue and/or function in patients with central nervous system (CNS) disorders. This paper describes a continuously dividing multipotent population of progenitor cells in the human embryonic forebrain that can be propagated in vitro. These cells can be maintained and expanded using a serum-free defined medium containing basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), and epidermal growth factor (EGF). Using these three factors, the cell cultures expand and remain multipotent for at least 1 year in vitro. This period of expansion results in a 10(7)-fold increase of this heterogeneous population of cells. Upon differentiation, they form neurons, astrocytes, and oligodendrocytes, the three main phenotypes in the CNS. Moreover, GABA-immunoreactive and tyrosine hydroxylase-immunoreactive neurons can be identified. These results demonstrate the feasibility of long-term in vitro expansion of human neural progenitor cells. The advantages of such a population of neural precursors for allogeneic transplantation include the ability to provide an expandable, well-characterized, defined cell source which can form specific neuronal or glial subtypes.

Tyrosine kinases are required for IFN-gamma-induced growth of human embryonic forebrain astrocytes

The cytokine IFN-gamma was shown to regulate growth and differentiation of human embryonic forebrain astrocytes. This work investigated a signalling pathway used by IFN-gamma during the process of growth regulation of human fetal astrocytes obtained from first trimester embryos. IFN-gamma induced significantly higher cell survival compared to that of unexposed cultures, and this survival could be suppressed by incubation with the tyrosine protein kinase (TPK) specific inhibitor tyrphostin A47 at the non-toxic concentration of 10(-6) M. The signal transducer and activator of transcription (STAT)-1 was translocated into the nucleus upon IFN-gamma stimulation, which was also blocked by incubation with A47. Our data demonstrate that TPKs are actively involved in growth regulation of the developing brain astrocytes induced by IFN-gamma.

Lift/transfer and technical aids for persons with severe acquired brain injury. An inventory of problems

A questionnaire about assistive devices for lift and transfer was distributed to all individuals evaluated at the Solberga Project outpatient service unit, a regional centre for long-term follow-up of severely brain injured persons in the Greater Stockholm area. The target group was 60 severely brain injured adults, of whom 57 (30 women and 27 men) answered a questionnaire created by one of the authors. The causes of injury in the study population were trauma (n = 27), cerebrovascular accident (n = 19), anoxia (n = 10) and other (n = 1). Thirty-two persons were quadriplegic after the injury and 21 were hemiplegic. More than half (33/57) reported problems with all five defined lift and transfer situations. Most (42/44) reported problems getting in and out of their wheelchairs. Technical aids were seldom used; 24 persons did not use any aids at all. The most commonly used aid was an adjustable bed. Most of the technical aids were used when the individual also had personal assistance. The persons who managed lift and transfer by themselves used few aids. It is reasonable to assume that severely brain injured individuals would be involved in more activities if they used technical aids more readily.