Cost-effectiveness analyses comparing cemented, cementless, hybrid and reverse hybrid fixation in total hip arthroplasty: a systematic overview and critical appraisal of the current evidence.

Background: This study aims to present an overview and critical appraisal of all previous studies comparing costs and outcomes of the different modes of fixation in total hip arthroplasty (THA). A secondary aim is to provide conclusions regarding the most cost-effective mode of implant fixation per gender and age-specific population in THA, based on high quality studies.Methods: A systematic search was conducted to identify cost-effectiveness analyses (CEAs) comparing different modes of implant fixation in THA. Analysis of results was done with solely CEAs that had a high methodological quality.Results: A total of 12 relevant studies were identified and presented, of which 5 were considered to have the methodological rigor for inclusion in the analysis of results. These studies found that either cemented or hybrid fixation was the most cost-effective implant fixation mode for most age- and gender-specific subgroups.Conclusion: Currently available well performed CEAs generally support the use of cemented and hybrid fixation for all age-groups relevant for THA and both genders. However, these findings were mainly based on a single database and depended on assumptions made in the studies' methodology. Issues discussed in this paper have to be considered and future work is needed.

Hip protectors are cost-effective in the prevention of hip fractures in patients with high fracture risk.

Cost-effective preventive interventions are necessary for tackling the increasing number of hip fractures, which are frequently occuring as a serious consequence of osteoporosis. Several interventions have been available for preventing and treating osteoporosis. The aim of this study was to systematically review and critically appraise studies that assessed cost-effectiveness of hip protectors for the prevention of hip fractures and to investigate the effects of age, gender and residence situation on cost-effectiveness. A systematic review was conducted in order to identify economic evaluation studies examining the hip protector solely or compared to no treatment according to the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Synthesis of results was performed to observe trends between the studies. Methodological quality of the studies was assessed by the use of the Quality of Health Economic Studies (QHES) instrument. A total of 15 economic evaluation studies were included for analysis. The methodological quality was high in most studies (13/15). The hip protector was solely evaluated in three studies and within 12 other studies compared with no intervention. All studies that investigated the cost-effectiveness in long-term care facilities revealed that hip protector use is a cost-effective strategy for the prevention of hip fractures in elderly. Cost-effectiveness was also observed in two studies that provided hip protectors in a geriatric hospital ward. Four studies included both community-dwelling residents and residents living in a long-term care facility in their study. These studies showed more variability regarding cost-effectiveness. One study did not report information regarding the residence situation of their cohort, but also observed cost-effectiveness. In conclusion, this review suggests that hip protectors are a cost-effective approach in the prevention of hip fractures in populations with high risk of hip fractures especially in long-term care facilities and a geriatric ward in a hospital.

Cemented versus cementless hemiarthroplasty for a displaced fracture of the femoral neck: a systematic review and meta-analysis of current generation hip stems.

AIMS: Our aim was to prepare a systematic review and meta-analysis to compare the outcomes of cemented and cementless hemiarthroplasty of the hip, in elderly patients with a fracture of the femoral neck, to investigate the mortality, complications, length of stay in hospital, blood loss, operating time and functional results. MATERIALS AND METHODS: A systematic review and meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines on randomised controlled trials (RCTs), studying current generation designs of stem only. The synthesis of results was done of pooled data, with a fixed effects or random effects model, based on heterogeneity. RESULTS: A total of five RCTs including 950 patients (950 hips) were included. Cementless stems were found to be associated with more complications compared with cemented stems (odds ratio (OR) 1.61, 95% confidence interval (CI) 1.12 to 2.31, p = 0.01), especially implant-related complications (OR 3.15, 95% CI 1.55 to 6.41, p = 0.002). The operating time was shorter for cementless stems (weighted mean difference -9.96 mins, 95%CI -12.93 to -6.98, p < 0.001). The data on functional outcomes could not be pooled. There was no statistically significant difference for any other outcome between the two methods of fixation. CONCLUSION: In hemiarthroplasty of the hip using current generation stems, cemented stems result in fewer implant-related complications and similar mortality compared with cementless stems. Cite this article: Bone Joint J 2017;99-B:421-31.

Variations in ventral root axon morphology and locomotor behavior components across different inbred strains of mice.

Locomotion is a complex behavior affected by many different brain- and spinal cord systems, as well as by variations in the peripheral nervous system. Recently, we found increased gene expression for EphA4, a gene intricately involved in motor neuron development, between high-active parental strain C57BL/6J and the low-active chromosome substitution strain 1 (CSS1). CSS1 mice carry chromosome 1 from A/J mice in a C57BL/6J genetic background, allowing localization of quantitative trait loci (QTL) on chromosome 1. To find out whether differences in motor neuron anatomy, possibly related to the changes in EphA4 expression, are involved in the motor activity differences observed in these strains, motor performance in various behavioral paradigms and anatomical differences in the ventral roots were investigated. To correlate the behavioral profiles to the spinal motor neuron morphology, not only CSS1 and its parental strains C57BL/6J (host) and A/J (donor) were examined, but also a set of other mouse inbred strains (AKR/J, 129x1/SvJ and DBA/2J). Significant differences were found between inbred strains on home cage motor activity levels, the beam balance test, grip test performance, and on alternating versus synchronous hind limb movement (hind limb hopping). Also, considerable differences were found in spinal motor neuron morphology, with A/J and CSS1 showing smaller, possibly less developed, motor neuron axons compared to all other inbred strains. For CSS1 and C57BL/6J, only genetically different for chromosome 1, a correlation was found between motor activity levels, synchronous hind limb movement and neuro-anatomical differences in spinal motor neurons. Inclusion of the other inbred strains, however, did not show this direct correlation. These data verifies the complex nature of the mammalian motor system that may be further dissected using genetic mapping populations derived from these inbred strains.

Intraspinal administration of an antibody against CD81 enhances functional recovery and tissue sparing after experimental spinal cord injury.

We previously demonstrated that the tetraspanin protein CD81 is up-regulated by astrocytes and microglia after traumatic spinal cord injury in rats and that CD81 is involved in adhesion and proliferation of cultured astrocytes and microglia. Since these reactive glial cells contribute to secondary damage and glial scar formation, we studied the effect of local administration of an anti-CD81 antibody in experimental spinal cord injury. Adult rats were subjected to a moderate spinal cord contusion injury and treated for 2 weeks with different doses of the anti-CD81 antibody AMP1 (0.5-5 microg/h) or non-immune IgG (5.0 microg/h). A technique was developed to infuse the antibodies directly into the lesion site via an intraspinal cannula connected to a pump. Functional recovery was monitored during 8 postoperative weeks by means of the Basso, Beattie and Bresnahan (BBB) locomotor rating scale, the BBB subscore and Grid-walk test. At the end of the study, quantitative histology was performed to assess tissue sparing. Our data showed that by itself cannulation of the lesion site resulted in minimal functional and histological impairments. Application of 0.5 microg/h AMP1 resulted in a marked functional recovery (BBB 2 points; Grid-walk 30% less errors compared to control). This recovery was accompanied by an 18% increase in tissue sparing at the lesion epicentre. No gross histological changes in glial scarring were apparent. Our data demonstrate beneficial effects of an anti-CD81 antibody on functional recovery in spinal cord injured rats and suggest that this effect is mediated through a reduction in secondary tissue loss.

Gene dosage-dependent transmitter release changes at neuromuscular synapses of CACNA1A R192Q knockin mice are non-progressive and do not lead to morphological changes or muscle weakness.

Ca(v)2.1 channels mediate neurotransmitter release at the neuromuscular junction (NMJ) and at many central synapses. Mutations in the encoding gene, CACNA1A, are thus likely to affect neurotransmitter release. Previously, we generated mice carrying the R192Q mutation, associated with human familial hemiplegic migraine type-1, and showed first evidence of enhanced presynaptic Ca(2+) influx [Neuron 41 (2004) 701]. Here, we characterize transmitter release in detail at mouse R192Q NMJs, including possible gene-dosage dependency, progression of changes with age, and associated morphological damage and muscle weakness. We found, at low Ca(2+), decreased paired-pulse facilitation of evoked acetylcholine release, elevated release probability, and increased size of the readily releasable transmitter vesicle pool. Spontaneous release was increased over a broad range of Ca(2+) concentrations (0.2-5mM). Upon high-rate nerve stimulation we observed some extra rundown of transmitter release. However, no clinical evidence of transmission block or muscle weakness was found, assessed with electromyography, grip-strength testing and muscle contraction experiments. We studied both adult ( approximately 3-6 months-old) and aged ( approximately 21-26 months-old) R192Q knockin mice to assess effects of chronic elevation of presynaptic Ca(2+) influx, but found no additional or progressive alterations. No changes in NMJ size or relevant ultrastructural parameters were found, at either age. Our characterizations strengthen the hypothesis of increased Ca(2+) flux through R192Q-mutated presynaptic Ca(v)2.1 channels and show that the resulting altered neurotransmitter release is not associated with morphological changes at the NMJ or muscle weakness, not even in the longer term.

Zinc amplifies mSOD1-mediated toxicity in a transgenic mouse model of amyotrophic lateral sclerosis.

Transgenic mice overexpressing the human mutated form (G93A) of Cu,Zn-superoxide dismutase (mSOD1) develop motor neuron degeneration resembling amyotrophic lateral sclerosis. In vitro studies have shown that mSOD1-induced, reactive oxygen species-mediated apoptosis of motor neurons depends on the presence of copper and the relative absence of zinc. Oral intake of zinc sulphate induces the expression of metallothioneins, enzymes that decrease oxidative stress, and leads to higher serum zinc, and lower copper levels. We therefore tested the effect of chronic oral administration of zinc sulfate (0.075 and 0.375 g/kg) on disease onset and survival of mSOD1 transgenic mice. We observed that zinc sulfate, rather than prolonging survival, decreased survival. We conclude that zinc sulfate amplifies the mSOD1 transgenic mouse phenotype. This finding may shed more light on the role of zinc in mSOD1-mediated toxicity.

Diagnostic value of sural nerve demyelination in chronic inflammatory demyelinating polyneuropathy.

The objective of the study was to determine the diagnostic value of features of demyelination and inflammation in sural nerve biopsy specimens of patients with chronic inflammatory demyelinating polyneuropathy (CIDP). The features of (i) demyelination, (ii) axonal de- and regeneration and (iii) inflammation were investigated by measuring the number of onion bulbs, g ratio (axon diameter/total nerve fibre diameter), myelinated nerve fibre density, number of clusters and endoneurial area in 21 patients with CIDP, as well as in 13 patients with chronic idiopathic axonal polyneuropathy (CIAP) and six autopsy controls. In addition, teased fibres were classified and lengths of internodes measured. We found no difference in demyelinating features between patients with CIDP and CIAP, as the percentage of fibres with segmental de- and remyelination and the number of onion bulbs were similar in both polyneuropathy groups. The g ratio, expected to be higher in a demyelinating disease due to thinner myelin sheaths, was significantly lower in CIDP than CIAP. Evidence for axonal degeneration was found in both CIDP and CIAP, as both showed a decrease in myelinated nerve fibre density. There was no evidence of endoneurial oedema in CIDP, as the endoneurial area did not differ between CIDP, CIAP and the autopsy controls. Although significant differences of features of demyelination, axonal degeneration and inflammation were found in sural nerve biopsy specimens, there was a considerable overlap between abnormalities in CIDP and CIAP patients. In the majority of patients, quantitative analysis of light microscopical abnormalities in sural nerves was similar in CIDP and CIAP. Therefore, a sural nerve biopsy is of limited diagnostic value in CIDP.

Cellular changes in motoneurons in a transgenic mouse model for amyotrophic lateral sclerosis as revealed by monoclonal antibody Py.

Transgenic mice (G93A) carrying the human amyotrophic lateral sclerosis (ALS) linked superoxide dismutase 1 (SOD1) mutations develop a motoneuron disease resembling human ALS. The affected motoneurons are characterized by the presence of cellular alterations. The antigen recognized by the monoclonal antibody Py is suggested to be associated with the neurofilamentous and microtubular elements of the cytoskeleton of specific neuron populations including the spinal motoneurons. The aim of the present study was to measure changes in the relative Py-immunoreactivity per identified Choline-Acetyl-Transferase (ChAT)-immunoreactive motoneuron during the disease progression. The relative Py-immunoreactivity of identified spinal motoneurons was measured on double stained (Py and ChAT) motoneurons using a digital imaging system coupled to an inverse microscope. A significant decrease of Py-immunoreactivity was already noted in the pre-symptomatic stages of the disease even before the onset of massive motoneuron degeneration. It is concluded that the Py-antibody detects early intracellular abnormalities related to neurodegenerative changes in spinal motoneurons of transgenic SOD1-(G93A) mice.

Rimmed vacuoles and the added value of SMI-31 staining in diagnosing sporadic inclusion body myositis.

Problems in diagnosing sporadic inclusion body myositis may arise if all clinical features fit a diagnosis of polymyositis, but the muscle biopsy shows some rimmed vacuoles. Recently, immunohistochemistry with an antibody directed against phosphorylated neurofilament (SMI-31) has been advocated as a diagnostic test for sporadic inclusion body myositis. The aims of the present study were to define a quantitative criterion to differentiate sporadic inclusion body myositis from polymyositis based on the detection of rimmed vacuoles in the haematoxylin-eosin staining and to evaluate the additional diagnostic value of the SMI-31 staining. Based on clinical criteria and creatine kinase levels in patients with endomysial infiltrates, 18 patients complied with the diagnosis of sporadic inclusion body myositis, and 17 with the diagnosis of polymyositis. A blinded observer counted the abnormal fibres in haematoxylin-eosin-stained sections and in SMI-31-stained sections. The optimal cut-off in the haematoxylin-eosin test was 0.3% vacuolated fibres. Adding the SMI-31 staining significantly increased the positive predictive value from 87 to 100%, but increased the negative predictive value only to small extent. We conclude that (1) patients with clinical and laboratory features of polymyositis, including response to treatment, may show rimmed vacuoles in their muscle biopsy and that (2) adding the SMI-31 stain can be helpful in differentiating patients who respond to treatment from patients who do not.

Automated blood-mixing devices still fail to mix at low bleeding rates.

BACKGROUND AND OBJECTIVES: The study evaluated mixing performance for various commercial blood-mixing devices at different flow rates. MATERIALS AND METHODS: A glycerol solution with a density equal to blood was pumped into a blood bag (mounted on a mixer) that contained 70 ml of Toluidin Blue in citrate-phosphate-dextrose (CPD). After 500 ml of glycerol solution had been pumped into the blood bag, the bag was emptied in fractions and the absorbance at 640 nm of each fraction (expressed as percentage of mixture absorbance) was plotted against the fraction number. RESULTS: At a flow rate of 30 ml/min, the curves were very sigmoid, with high initial values that decreased during collection of the fractions. The absorbance values of the fractions collected later (after approximately 250-300 ml) were 10-50% (i.e. percentage of absorbance for complete mixing) for the different mixers, indicating that the CPD solution was incompletely mixed with the incoming solution, resulting in a lower-than-expected 'anticoagulant' content for the fractions collected later. At a flow rate of 50 ml/min the mixing was improved, but only at 75 ml/min did all mixers show relatively good mixing. Manual mixing, by kneading the bag three times/min, gave at all rates an almost ideal mixing curve, 105% initially to 90% in the final fractions. CONCLUSION: At relatively high bleeding rates, all mixers performed well, although complete mixing was only obtained with manual kneading. However, most blood-mixing devices still fail to mix efficiently at normal and low bleeding rates. Although the minimal degree of necessary mixing is unknown, further optimization of mixing devices seems warranted.

Collagen IV deposits do not prevent regrowing axons from penetrating the lesion site in spinal cord injury.

Scarring is suggested to impede axon regrowth across the lesion site in the injured adult mammalian central nervous system. Collagen Type IV, as a major component of the scar formed after injury, is an impediment for successful axonal regeneration and a decrease in its amount is a prerequisite for regrowing axons to cross the lesion in the postcommissural fornix in the injured adult rat (Stichel et al. [1999] Neurosci. 93:321-333). The aim of the present study was to analyze the relationship between collagen IV deposits and regrowing axons at various times after dorsal hemi-section of the adult rat spinal cord. Immunohistochemical double staining revealed that penetrating neurofilament-positive axons and collagen IV deposits were co-localized in the lesion site in the initial stages of axonal sprouting (between 7 and 14 days post-operatively) and were still present 1 and 2 months post-operatively. Interestingly, collagen IV-immunoreactive areas located around cystic cavities formed at the site of injury 1 month post-operatively, were devoid of axons. In conclusion, our observations indicate that collagen IV deposits after spinal cord injury do not prevent neurofilament-positive regrowing axons from penetrating the lesion site.

Low leukocyte contamination without filtration by preparation of platelet concentrates in cylindrical bags with the buffy-coat method.

BACKGROUND AND OBJECTIVES: The buffy-coat (BC) method for platelet concentrate (PC) preparation was modified in order to obtain leukodepleted PCs from single BCs without filtration. MATERIALS AND METHODS: BCs were centrifuged in cylindrical BC bags and the optimal centrifugation conditions and optimal hematocrit were determined. RESULTS: With optimal conditions, a tenfold lower leukocyte contamination was obtained compared with the conventionally shaped, wide BC bag (0.3 +/- 0.19 versus 3.0 +/- 1.71 x 10(6) leukocytes per unit; 85-ml BCs). The platelet yield obtained with the cylindrical bag did not differ significantly from the yield obtained with the conventional bag (56 +/- 16.4 versus 61 +/- 15 x 10(9) platelets per PC). Furthermore, when PCs were prepared from 100-ml BCs in cylindrical bags, a leukocyte contamination of 0.2 +/- 0.11 x 10(6) and a platelet content of 61 +/- 13.5 x 10(9) per PC were obtained. CONCLUSION: The use of cylindrical BC bags reduced the leukocyte contamination in PCs to a level required for leuko-depletion without affecting platelet recovery.

Thickness of endoneurial vessel basal lamina area in chronic idiopathic axonal polyneuropathy.

For chronic idiopathic axonal polyneuropathy (CIAP), even after extensive evaluation, no cause has yet been found. Considering the age and sex distribution of patients with this disease, it is possible that vascular disease plays a role in the development of this polyneuropathy. As endoneurial vessel abnormalities can be related to ischemia, we investigated endoneurial vessels in sural nerve biopsies of 18 patients with CIAP. As controls we used sural nerves of 4 patients with diabetes mellitus, 6 patients with hereditary motor and sensory neuropathy type II (HMSN type III) and 10 autopsy cases. Basal lamina area thickness, endothelial cell area, lumen area, and the number of basal laminae, endothelial cells and periendothelial cell nuclei were investigated. Basal lamina area thickness, endoneurial cell area and number of endothelial cell nuclei in CIAP were increased in comparison with HMSN type III, whereas the basal lamina area thickness of patients with CIAP and diabetes mellitus were in the same range. The structure of the basal lamina area in CIAP differed from diabetes mellitus; in diabetes mellitus there was a larger number of lamellae, whereas in CIAP there was an increase in collagen. There was no correlation between basal lamina area thickness and age. In CIAP patients with peripheral vascular disease of the legs, basal lamina area thickness was increased. The relation between basal lamina area thickening and peripheral vascular disease of the legs in CIAP may indicate a role for ischemia in the development of this polyneuropathy.

Comparison between a new PVC platelet storage container (UPX80) and a polyolefin container.

During storage of platelet concentrates (PCs), the quality of the platelets deteriorates gradually, partially dependent on gas exchange. UPX80 (JMS, Japan) 1-L platelet storage PVC containers with increased gas transport capacity were compared with 1- and 1. 5-L polyolefin (PO) containers (NPBI, the Netherlands) with filtered PCs stored either in GAC (gluconate-acetate-citrate, < 10% plasma) or in plasma, for 8 days. In total 32 PCs were made (260-330 x 109 platelets per concentrate), equally divided over different bags and storage media. During storage, gas exchange, metabolic, physical and activation parameters were measured. No consistent differences for all parameters were observed between UPX80 and PO containers (1-L or 1.5-L). Blood gas parameters indicated better gas exchange for UPX80 containers compared with PO containers. Good morphology was observed in UPX80 and metabolic functions were not significantly different compared with PO containers. During prolonged storage (after day 6), some significant differences in CD62P and CD63 expression were found, indicating a higher degree of platelet activation in UPX80 containers, especially in GAC. UPX80 PC containers are suitable for storage of PCs. Although in UPX80 better gas exchange is demonstrated, as compared with PO containers, this does not improve the platelet quality during storage for 6 days, indicating that gas exchange above the level of PO containers has no effect on the switch to aerobic metabolism in platelets.

Unmyelinated nerve fiber degeneration in chronic inflammatory demyelinating polyneuropathy.

To determine whether unmyelinated nerve fibers escape degeneration as one might expect in an immune response exclusively directed at myelin, we performed a morphometric examination of unmyelinated axons and myelinated nerve fibers in sural nerve biopsy specimens of 14 patients with a chronic inflammatory demyelinating polyneuropathy (CIDP) and of 12 age-matched normal controls. The numbers of unmyelinated axons, myelinated nerve fibers, denervated Schwann cell units and collagen pockets were quantified and related to the clinical and electrophysiological data of the patients with CIDP. In 4 patients with a rapid onset of the neuropathy and a highly elevated CSF protein, the numbers of both unmyelinated axons and myelinated nerve fibers were decreased equally. In 8 patients we found that the unmyelinated axons were relatively spared compared with the loss of myelinated nerve fibers. In these patients, however, the presence of denervated Schwann cell units and of collagen pockets was increased. We conclude that unmyelinated nerve fibers are affected in patients with CIDP.

Pre- and postsynaptic localization of RC3/neurogranin in the adult rat spinal cord: an immunohistochemical study.

RC3 (neurogranin; BICKS) is a neuron-specific calmodulin-binding protein kinase C substrate. Thus far, immunohistochemical studies on the localization of RC3 revealed its presence in all neuronal phenotypes, which were restricted to specific areas in the neostriatum, the neocortex, and the hippocampus. RC3 was mostly found in cell bodies and dendrites, with some infrequent presence in axonal profiles, i.e. in the internal capsule. Until now, RC3 expression was reported to be absent in the adult rat spinal cord. RC3 might, however, act as an intermediate of protein kinase C-mediated signaling pathways during synaptic development and plasticity. We hypothesized a role for this 78-amino-acid protein in dendritic plasticity occurring after spinal cord injury. To our surprise, an immunohistological analysis of the uninjured adult rat spinal cord revealed the presence of RC3-positive cell bodies and dendrites in specific regions in the gray matter. Interestingly, axon-containing structures, such as the dorsal and ventral corticospinal tract, were also found to be RC3-positive. This axonal labeling was confirmed by preembedding electron microscopy. In conclusion, we demonstrate here that RC3 is present in the adult rat spinal cord in pre- and postsynaptic structures.

The diagnostic value of sural nerve T cells in chronic inflammatory demyelinating polyneuropathy.

BACKGROUND: T-cell infiltrates in sural nerve biopsy specimens of patients with inflammatory neuropathies have been reported, suggesting a role for T cells in the pathogenesis, but the specificity of the presence and localization of sural nerve T cells in chronic inflammatory demyelinating polyneuropathy (CIDP) is unknown. OBJECTIVE: To study the diagnostic value of the number and distribution of sural nerve T cells in CIDP. METHODS: We performed a quantitative immunohistochemical examination of T cells in sural nerve biopsy specimens taken from 23 patients with a CIDP and compared them with sural nerves of 15 patients with a chronic idiopathic axonal polyneuropathy (CIAP), 5 patients with a vasculitic neuropathy, and 10 normal controls. RESULTS: T cells were found in sural nerves of all CIDP patients as well as in all disease and normal controls. Only six CIDP patients had increased numbers and densities of T cells compared with CIAP patients and controls. Based on the distribution of endoneurial or epineurial T cells, it was not possible to differentiate CIDP patients from CIAP patients or normal controls. In patients and controls perivascular epineurial T cells predominated. Increased numbers and densities of sural nerve T cells in patients with CIDP were associated with female sex, a more severe disease course, worse outcome, highly elevated CSF protein level, and a larger sural nerve area, but not with loss of myelinated nerve fibers in the sural nerve biopsy sample or demyelinating features on electrophysiologic examination. CONCLUSIONS: In the majority of CIDP patients, the number and distribution of T cells in sural nerve biopsy samples were similar to patients with noninflammatory neuropathies and normal controls. Only large numbers of sural nerve T cells are specific for inflammatory neuropathies and therefore of diagnostic value for CIDP.

Differential distribution of immunoreactivity in the developing rat spinal cord revealed by the monoclonal antibody Py.

Monoclonal antibody Py was developed as a useful tool for the identification of large diameter neurons of the adult rat central nervous system [Woodhams et al., J. Neurosci., 9 (1989) 2170-2181]. Here, we present a detailed light-microscopic study of the distribution of Py-immunoreactivity in the developing rat spinal cord. The first cells which demonstrated Py-immunoreactivity were the motoneurons in layer IX of the gray matter at embryonic day 15. These cells, including their axons and dendrites, remained Py-immunoreactive throughout subsequent developmental stages into adulthood and were the most intensely stained cells in the adult rat spinal cord. Other cell populations which became Py-immunoreactive during development were neurons in layers III-VIII, and large-to-medium diameter neurons of the dorsal root ganglion (DRG). Transient Py-immunoreactivity was observed in the distal portions of DRG axons as well as in the ascending fibers in the dorsal funiculus. Py-immunoreactive fibers could be detected in the ventral most part of the dorsal funiculus (corticospinal tract area), even at embryonic ages prior to the arrival of corticospinal fibers. The localization and transient expression of the antigen recognized by the Py-antibody in developing rat spinal cord strongly suggests an important role of this molecule in stabilization and/or plasticity of the neuronal cytoskeleton. The results presented here form the foundation for the use of Py-immunocytochemistry to study well-defined cell populations under a range of experimental and pathological conditions.

Oxidant treatment causes a dose-dependent phenotype of apoptosis in cultured motoneurons.

Evidence is growing that reactive oxygen species (ROS), by-products of (normal) cellular aerobic metabolism, are involved in the pathogenesis of neurodegenerative diseases. One of these diseases is amyotrophic lateral sclerosis (ALS), in which motoneurons die, leading to paralysis and death. It remains uncertain whether ROS are the cause of (apoptotic) motoneuron death in ALS. To further understand the role of ROS in motoneuron death, we investigated the effects of ROS on isolated spinal rat motoneurons in culture. ROS were generated with a combination of iron(III) and ascorbate, or with hydrogen peroxide. Both toxic treatments resulted in a dose-dependent motoneuron death. Iron(III)/ascorbate toxicity was completely prevented with the hydrogen peroxide detoxifying enzyme catalase and partially prevented with the antioxidant vitamin E. SOD1, the enzyme that removes superoxide, did not protect against iron(III)/ascorbate toxicity. ROS treatment caused apoptotic motoneuron death: low doses of iron(III)/ ascorbate or hydrogen peroxide resulted in complete apoptosis ending in nuclear fragmentation, while high doses of ROS resulted in incomplete apoptosis (nuclear condensation). Thus, depending on the dose of ROS, the motoneurons complete the apoptotic pathway (low dose) or are stopped somewhere during this route (high dose).