Alterations in neuronal gene expression profiles in response to experimental demyelination and axonal transection

The main pathological features of multiple sclerosis, demyelination and axonal transection, are considered to cause reversible and irreversible neurological deficits, respectively. This study aimed to separately analyze the effects of these pathological hallmarks on neuronal gene expression in experimental paradigms. The pontocerebellar pathway was targeted with either lysolecithin-induced chemical demyelination or a complete pathway transection (axonal transection) in rats. Transcriptional changes in the pontocerebellar neurons were investigated with microarrays at days 4, 10 and 37 post-intervention, which was confirmed by immunohistochemistry on protein level. A common as well as unique set of injury-response genes was identified. The increased expression of activating transcription factor 3 (Atf3) and thyrotropin-releasing hormone (Trh) in both injury paradigms was validated by immunohistochemistry. The expression of Atf3 in a patient with Marburg's variant of multiple sclerosis was also detected, also confirming the activation of the Atf3 pathway in a human disease sample. It was concluded that this experimental approach may be useful for the identification of pathways that could be targeted for remyelinative or neuroprotective drug development.

Regional distribution and effects of postmortal delay on endocannabinoid content of the human brain

Tissue levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) have been determined in 16 regions and nuclei from human brains, using liquid chromatography/in-line mass spectrometry. Measurements in brain samples stored at -80 degrees C for 2 months to 13 years indicated that endocannabinoids were stable under such conditions. In contrast, the postmortal delay had a strong effect on brain endocannabinoid levels, as documented in brain samples microdissected and frozen 1-6 h postmortem, and in neurosurgical samples 0, 5, 30, 60, 180 and 360 min after their removal from the brain. The tissue levels of AEA increased continuously and in a region-dependent manner from 1 h after death, increasing about sevenfold by 6 h postmortem. In contrast, concentrations of 2-AG, which were 10-100 times higher in human brain regions than those of AEA, rapidly declined: within the first hour, 2-AG levels dropped to 25-35% of the initial ('0 min') value, thereafter they remained relatively stable. As analyzed in samples removed 1-1.5 h postmortem, AEA levels ranged from a high of 96.3 fmol/mg tissue in the nucleus accumbens to a low of 25.0 fmol/mg in the cerebellum. 2-AG levels varied eightfold, from 8.6 pmol/mg in the lateral hypothalamus to 1.1 pmol/mg in the nucleus accumbens. Relative levels of AEA and 2-AG varied from region to region, with the 2-AG:AEA ratio being high in the sensory spinal trigeminal nucleus (140:1), the spinal dorsal horn (136:1) and the lateral hypothalamus (98:1) and low in the nucleus accumbens (16:1) and the striatum (31:1). The results highlight the pitfall of analyzing endocannabinoid content in brain samples of variable postmortal delay, and document differential distribution of the two main endocannabinoids in the human brain.

Safety of long-term combined immunosuppressive treatment in myasthenia gravis – analysis of adverse effects of 163 patients

The aim of this study was to evaluate the long-term adverse effect (AE) profile of azathioprine (AZA) plus methylprednisolone combined immunosuppressive treatment in myasthenia gravis (MG) in a larger patient cohort. A prospective, open, observational study was conducted on 163 MG patients treated with combined immunosuppressive medication for a mean duration of 35.5 months (range 9-79 months). During the treatment course, AEs occurred in 61.4% of patients; 18% of these patients developed both steroid- and AZA-related AE, 15% had purely AZA-related AE and 67% had steroid-associated AEs. Severe AEs were encountered in only 6.7% of patients in whom treatment had to be discontinued. The clinical severity of MG at the start of the immunosuppressive treatment was positively correlated with the frequency and severity of AEs during the treatment, and patients with severe MG were found to be at higher risk of developing AEs during the combined immunosuppressive treatment. Combined immunosuppressive treatment of MG patients is well tolerated, and severe AEs requiring treatment cessation are rare. The incidence of steroid-related AEs is high during long-time therapy which underlines the importance of its combination with AZA. The probability of developing AEs seems to correlate with the severity of MG at the beginning of the treatment.

Expression of the Krüppel-type zinc finger protein rKr2 in the developing nervous system

Zinc finger transcription factors of the Krüppel-class figure prominently in cell fate specification and differentiation in the nervous system. One of the Krüppel-type genes that was originally cloned from an oligodendrocyte library by virtue of its homology with the prototypic Krüppel motif is the rat rKr2 gene (Pott et al., 1995). In primary cultures of rat glial cells, the rKr2 protein was only present in the oligodendrocyte lineage, predominantly in progenitors. Ninety percent of A2B5(+) oligodendrocyte progenitors displayed rKr2 immunoreactivity, while most MBP(+) oligodendrocytes lacked detectable rKr2. A similar pattern was found in vivo, in which the peak expression of rKr2 in the oligodendrocyte lineage of rats coincided with the wave of progenitor proliferation in early postnatal life. The subventricular zone, a source of neuronal and glial progenitors, displayed intense staining for rKr2 at late embryonic and postnatal stages. In the adult, cells within the remnants of this germinal zone continued to express rKr2 protein strongly. Some populations of mature neurons also displayed rKr2 immunostaining. Astrocytes and microglia were not labeled with the polyclonal anti-rKr2 antibody in vitro or in vivo. At all developmental stages, the rKr2 protein was localized to the nucleus. The stage-specific expression pattern and the subcellular localization of rKr2 recommend a role for this Krüppel-type gene in the progression of neural stem cells and in the early development of the oligodendrocyte lineage.

Increased c-Jun expression in neurons affected by lysolecithin-induced demyelination in rats

The objective of this study was to investigate whether the expression of c-Jun is involved in the neuronal response to experimental demyelination. Lysolecithin-induced demyelination was generated in two distinct neural systems in rats: in the pontocerebellar and the septohippocampal pathways. Six days after the stereotaxic injections of lysolecithin, expression of the immediate early gene c-Jun was visualized by immunohistochemistry. Lesion-specific expression of the Jun protein was observed in neurons whose axons transverse the demyelinated area. Unlike the neural response to axotomy, lysolecithin treatment did not alter the expression of the neuropeptide galanin in the septohippocampal pathway. These results suggest that c-Jun protein expression might represent one step in the neuronal response to demyelination and that this response might be distinct in its downstream events from axotomy.

Adult Attachment Interview: linkages with dimensions of emotional availability for mothers and their pre-kindergarteners

Maternal attachment representations were assessed using the George, Kaplan, and Main (1985) Adult Attachment Interview (AAI), and emotional availability during observed mother-child interactions was assessed using the third edition of the Emotional Availability (EA) Scales (Biringen, Robinson, & Emde, 1998). This edition of EA included four parental scales and two child scales (Maternal Sensitivity, Structuring, Nonintrusiveness and Nonhostility; and Child Responsiveness and Child Involvement). Separate Hierarchical Multiple Regressions (HMRs) were computed to examine the prediction of the separate EA dimensions from demographic information, the AAI classification, and AAI scales. These analyses indicated that each of the EA dimensions (with the exception of maternal nonintrusiveness and nonhostility) was predicted by the AAI classification and/or AAI scales. Using three-step HMRs, the strongest prediction was for maternal sensitivity where 54% of the total variance in maternal sensitivity was explained by maternal education, AAI classification, and AAI 'state of mind' scales. Maternal nonhostility was predicted by maternal education and gender of the child, with lower-income mothers and mothers of girls demonstrating greater hostility.

Axonal changes in chronic demyelinated cervical spinal cord plaques

Imaging and pathomorphological studies in multiple sclerosis suggest that axonal injury and axonal loss are playing a crucial role in those with persistent disability and long-standing disease. Although the existence of axonal injury in multiple sclerosis is proven, especially in the zone of active inflammation, the effect of chronic inflammation on the axons remains elusive. The aim of this study was to perform a quantitative morphometrical analysis, estimating axonal loss and evaluating axonal degenerative changes in cervical spinal cord samples of patients suffering from secondary progressive multiple sclerosis. Completely demyelinated plaques, normal appearing white matter (NAWM) and control material from anatomically identical regions of the cord have been compared. Neurofilament immunostaining was used for identification of the axons. We observed a significant reduction of axonal density (number of axons/mm(2)) in multiple sclerosis, both in the plaque and in the NAWM compared with the control cases. Axons under approximately 3.3 microm diameter seemed to be more affected. The intensity of the immunostaining was significantly reduced in the plaque compared with either NAWM or control. Our results on the cervical cord combined with other observations support the concept of slow axonal degeneration rather than acute damage as a cause of chronic disability in multiple sclerosis.

Neuroprotective effect of GYKI 52466 on AMPA-induced neurotoxicity in rat striatum

The neuroprotective effect of intraperitonally administered GYKI 52466 (2,3-benzodiazepine derivate) was investigated on AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxalon-propionic acid)-induced neuronal degeneration in the striatum of adult rats. The dose-dependent neurotoxic effect of AMPA was evaluated by the decrease in the activity of choline acetyltransferase (ChAT), due to degeneration of cholinergic neurons. An injection of 25 mg/kg GYKI 52466 30 min prior to the striatal application of 50 nmol AMPA, followed by repeated application of GYKI 52466 (10 times 5 mg/kg at 10 min intervals, reaching a final dose of 75 mg/kg) was able to prevent neuronal damage monitored by ChAT activity. Conversely, co-injection of GYKI 52466 (50 and 75 mg/kg) with AMPA (50 and 100 nmol) did not elicit any significant protection against the neuronal loss as measured by the ChAT enzyme activity. Therefore, one dose of agonist decreasing ChAT activity by about 40% (50 nmol) was tested on [3H]girisopam binding sites and on the immunoreactivity of glial fibrillary acid protein. The lesions were measured on methylene blue-stained serial sections with a computer assisted image analysis program (NIH Image 1.60). As a result of the AMPA treatment [3H]girisopam binding sites became depleted, and the immunoreactivity of glial fibrillary acid protein increased and on the site of the injection in the striatum a lesion developed. In the presence of AMPA (50 nmol) administered intrastriatally, GYKI 52466 (75 mg/kg i.p.) was able to make the radioactive signal of [3H]girisopam reappear. The volume of AMPA induced neuronal damage in the striatum and the extent of gliosis was reduced. These data provide evidence for the neuroprotective effect of GYKI 52466, and suggest a potential therapeutic value in some neurological disorders.

Binding of girisopam (a 2,3-benzodiazepine derivative) to the substantia nigra is prevented by lesioning of the striatonigral pathway

The binding sites of girisopam, a homophthalazine (2,3-benzodiazepine)-derivate have a specific distribution pattern restricted to the striato-pallido-nigral system of the rat brain. Following kainic acid lesions in the caudate-putamen or the ventral striatum (nucleus accumbens, olfactory tubercle), as well as after surgical transection of the striatonigral pathway, [3H]girisopam binding sites were reduced or completely eliminated from the substantia nigra and the entopeduncular nucleus. Kainic acid lesions of the globus pallidus failed to act on girisopam binding sites in the substantia nigra. Surgical transections or 6-hydroxydopamine lesions of the striatonigral pathway, as well as intranigral kainic acid injections did not influence binding sites in the striatum or the pallidum. These findings indicate that girisopam in the striatum to be postsynaptic on striatonigral projecting neurons. Girisopam in the striatum seems is present in striatonigral projecting neurons. The binding sites are transported from the striatum (mainly from the caudate-putamen, partly from the ventral striatum) to the substantia nigra and the entopeduncular nucleus. The exact identity of these striatonigral fibres bearing homopthalazines is uncertain.

Ethanol inhibition of stress-related tachycardia involves medullary NMDA receptors

In rats, neurons in the perifornical area of the hypothalamus send descending projections to the commissural part of the nucleus tractus solitarii as demonstrated by an anterograde tracer study. In urethane-anaesthetised rats, stimulation of neurons in the perifornical area by microinjection of bicuculline or 6-OH-saclofen causes tachycardia and inhibits baroreflex bradycardia. The effects elicited from the perifornical area are similar in magnitude to those elicited from the adjacent dorsomedial nucleus, also called the hypothalamic defense area. Microinjection into the nucleus tractus solitarii of the NMDA (N-methyl-D-aspartate) receptor antagonist, AP-7 (2-amino-7-phosphonoheptanoic acid), inhibits the tachycardic response to stimulation of the perifornical area. Injection of ethanol intravenously or into the nucleus tractus solitarii also inhibits this tachycardic response, but causes no further inhibition when combined with AP-7. We conclude that the perifornical area is part of the hypothalamic defense area, and it is under strong, tonic GABAergic inhibition mediated by both GABAA and GABAB receptors. Furthermore, descending input from the perifornical area to the nucleus tractus solitarii is via an NMDA synapse, and ethanol inhibits stress-related tachycardia by inhibiting these NMDA receptors in the nucleus tractus solitarii.

Influence of insulin on the movement of Tetrahymena pyriformis. Hormonal imprinting alters the velocity

Treatment with insulin, cyclic adenosine monophosphate (cAMP) or theophylline, which uniformly influence the intracellular cAMP level, accounted for appreciable changes in the movement of Tetrahymena pyriformis. All applied treatments caused a quantitative decrease in the percentage of relatively rapid movements (straight and spiral swimming) and a proportional increase in that of slow movements (standing, turn, creeping). A single treatment with insulin caused a quantitative decrease in fast movements and a quantitative increase in slow movements also in the offspring generations and reexposure to insulin had a similar, but even stronger effect.

S-100 protein content of dermal and oral mucosal blue nevi

Three common blue nevi from skin of the trunk and upper extremities, and 5 from oral mucosae were studied using an immunoperoxidase stain for S-100 protein. The skin lesions were uniformly negative whereas all of the oral mucosal lesions contained numerous positively stained dendritic cells. This difference may, in part, be explained by the different embryologic origins of the connective tissue stromas; the connective tissues of the head and neck are thought to be of neural crest origin whereas the connective tissues in the rest of the body are of mesodermal origin. These findings strengthen and refine the association between S-100 protein content and neural crest derivation.

Langerhans cells in verruciform xanthomas: an immunoperoxidase study of 10 oral cases

Ten oral verruciform xanthomas were studied using an immunoperoxidase stain for S-100 protein. All cases exhibited positively stained dendritic cells among the mononuclear inflammatory cell infiltrate at the base of the lesions and to a lesser extent among the "foam cells". The foam cells were, however, negative for S-100 staining. We suggest that, based on these findings, verruciform xanthomas belong to a new category of "non-X histiocytoses" in which the presence of Langerhans cells suggests an immunologic pathogenesis.