摘要:

AbstractPrevious studies from our laboratory showed the development of circulating T lymphocytes sensitized to myelin basic protein (MBP) in guinea pigs challenged with MBP. Also, lymphocytes sensitized to MBP were found in patients with multiple sclerosis (MS). In this report, we describe the kinetics of MBP‐sensitized lymphocytes in a longitudinal study (140–316 days) of seven MS patients using the MBP‐stimulated active rosette‐forming T cell assay (MBP‐ARFC). Expressed as the ratio of MBP‐ARFC over ARFC (early and 37°C stable rosette‐forming T lymphocytes without added antigen), the results show a considerable degree of variation in the levels of MBP‐ARFC. Although the levels of ARFC during the study period were relatively unchanged for each patient, increases in the MBP‐ARFC/ARFC ratios were associated with the development of neurological symptoms of disease. The results of this study demonstrate the development of T‐cell‐mediated immunity to MBP in patients with MS. Detection of MBP‐sensitive cells was possible during the course of the disease. The level of sensitivity was influenced by the clinical status, degree of neurological deficit, and par

ISSN:0360-4012    

DOI:10.1002/jnr.490130302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractExtracts of bovine heart, rat heart, and rat skeletal muscle were chromatographically separated and the fractions tested for their ability to maintain the survival of dissociated sympathetic, parasympathetic, and sensory neurones. Bovine heart contained at least five, rat heart at least six, and rat skeletal muscle at least four active components differing in their physicochemical properties and their target selectivity. Bovine and rat heart appeared to contain at least two components in common. The differences in active components found in the three tissues are consistent with a complex and perhaps tissue‐specific system regulating neuronal surviva

ISSN:0360-4012    

DOI:10.1002/jnr.490130303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractIn primary cultures of neurons and astrocytes from rat brain, the cellular contents of K+and Na+were used to assess plasma membrane permeability in response to osmotic shock. In contrast to trypan blue exclusion, the measure of ionic content reflected both transient and permanent membrane damage, and was also applicable to aggregates of cells. In steady state, the neurons and glia exhibited a K+to Na+ratio of 3–5, and the mean cellular contents (μEq/mg protein) of K+and Na+were 0.72 and 0.17 for astrocytes and 0.78 and 0.23 for neurons. Both hypo‐ and hypertonicity resulted in marked efflux of cell K+, but elevation of cellular Na+occurred only under severe hypertonic conditions. Relative to neurons, astrocytes displayed considerably higher resistence to osmotic shock. During subsequent isotonic incubation, these cells were able to completely recover from transient membrane damage caused by a 10‐min exposure to fourfold hypertonicity. Permanent changes in glial permeability were obtained only after a 20‐min hypertonic shock. In contrast, 5 min hypertonic treatment of neurons decreased the ratio of cellular K+to Na+from 4.5 to 1. This ratio was restored twofold by isotonic incubation, but decreased permanently to below 1 after 10 min of hypertonic shock. The results describe marked differences in the osmotic fragility of neurons and glia and demonstrate that the determination of cellular K+and Na+provides a sensitive and accurate indicator of membrane permeability in neural cells propagated as surface‐growing cultures. The approach has wide‐ranging a

ISSN:0360-4012    

DOI:10.1002/jnr.490130304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractSynthesis of arachidonoyl CoA and docosahexaenoyl CoA in homogenates and microsomes from cerebrum, cerebellum, and brain stem and in synaptic plasma membranes from cerebrum of control rats and rats undergoing bicuculline‐induced status epilepticus were studied. Arachidonoyl CoA synthesis was 3–5 times higher than docosahexaenoyl CoA in homogenates and microsomes. The synaptic plasma membranes showed only 1.5‐ to 2.5‐fold higher activity. The presence of Triton X‐100 (0.1%) in the incubation medium did not alter the activity of arachidonoyl CoA synthesis but did increase the synthesis of docosahexaenoyl CoA in homogenates, microsomes, and especially in synaptic plasma membranes. The synthesis of these polyenoic fatty acyl CoAs were 4–6 times higher in microsomes than in homogenates. Synaptic plasma membranes exhibited about the same amount of activity as homogenates in the synthesis of docosahexaenoyl CoA, but only half the activity of the latter in arachidonoyl CoA synthesis. The synthesis of arachidonoyl CoA and docosahexaenoyl CoA in cerebral homogenates and microsomes was higher than that of cerebellum and brain stem.The apparent Km values for labeled arachidonic acid (17 μM) and docosahexaenoic acid (12 μM) in synaptic plasma membranes were lower than the values for microsomes isolated from different brain regions. The Vmaxvalues were also 4–10 times lower. Microsomes from different regions did not differ in their apparent Km values, but did show variations in apparent Vmaxvalues. Cerebellar microsomes showed lower Vmaxvalues than the other two regions. The presence of Triton X‐100 caused a significant decrease in the apparent Km values with little change in the Vmaxvalues. Bicuculline‐induced seizures did not alter the kinetic properties of arachidonoyl CoA and docosahexaenoyl CoA synthesis, except there was a significant decrease in the apparent Km and Vmaxvalues for cerebellar microsomal docosahexaenoyl CoA synthesis. In conclusion, there were marked differences in the activation of polyenoic fatty acids in different parts of the brain and in subcellular fractions. Although bicuculline‐induced convulsions accumulate free polyenoic fatty acids in the brain, no changes were detected when the fatty activation was assayed with exogenous cofactors,

ISSN:0360-4012    

DOI:10.1002/jnr.490130305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThere are two types of calcium‐activated neutral protease (CANP), m‐CANP and μ‐CANP, following the nomenclature of Suzuki et al to show that each requires mM and μM Ca2+, respectively, for its activation. We found μ‐CANP activity in a crude CANP fraction extracted from the peripheral nerve, which degraded the neurofilament (Nf) triplet (200 K, 160 K, 68 K), especially the 160 K component, at Ca2+concentrations of 50 μM and 0.1 mM. The triplet was degraded in the order of the 160 K, 68 K, and 200 K components, respectively. In addition, the effects of partially purified μ‐CANP of rabbit skeletal muscle, purified natural μ‐CANP of bovine liver, derived μ‐CANP prepared by autodigestion of chicken muscle m‐CANP, m‐CANP of chicken skeletal muscle, and cathepsin B of rat liver on the Nf were examined. Among the triplet components, the 160 K component was most rapidly degraded by all proteases so far tested. The difference in the effect of μ‐CANP and m‐CANP or cathepsin B on susceptibility of the 200 K component to degradation might be due to the difference of the rela

ISSN:0360-4012    

DOI:10.1002/jnr.490130306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractDietary taurine deprivation adversely affects feline pregnancy and is associated with the frequent occurrence of fetal resorption, abortion, stillbirth, and low birthweight of live kittens at term. Taurine‐deprived, live‐born kittens have a poor postnatal survival rate and grow less well than kittens from taurine‐supplemented queens. The postnatal dietary taurine intake of such kittens is reduced if they are nursed by their biologic mothers; the concentration of taurine in milk of taurine‐deprived mothers is less than 10% of that in milk from taurine‐supplemented queens. Surviving kittens from taurine‐deprived mothers exhibit a constellation of neurological abnormalities (abnormal hind leg development, a peculiar gait characterized by excessive abduction and paresis, and thoracic kyphosis readily visible by X‐ray). These findings suggest the presence of a developmental cerebellar deficit. Histological examination of the pre‐ and postnatally taurine‐deprived kitten's cerebellum reveals a persistence of the external granule cell layer, which was confirmed by electron‐microscopic examination. Numerous mitotic figures are present in the cells in the external granule cell layer of the cerebellum of kittens born from and nursed by taurine‐deprived queens, but not in those from taurine‐supplemented mothers. These findings sugge

ISSN:0360-4012    

DOI:10.1002/jnr.490130307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractAn unequal decrease in cholinergic activity has been evidenced in discrete brain areas in the growth hormone, thyroid‐stimulating hormone and prolactin deficient Snell dwarf mouse. The effect of the mutation's pituitary deficit on central cholinergic mechanisms appears to be selective: Normally high cholinergic activity areas such as striatum, olfactory tubercles, and hippocampus show strong alterations in this neurotransmitter system. Structures which appear earlier in ontogenesis are less affected, if at all. The lack of pituitary hormones seems to have effects on choline acetyltransferase activity and/or synthesis as well as on the development of high affinity (H. A.) cholinergic uptake mechanisms, both strongly defective in hippocampus and striatum. Therefore, a lower density of cholinergic terminals can be inferred. Furthermore, our observations are consistent with a close functional coupling of the choline H. A. transport and of subsequent choline acetylation. Acetylcholinesterase activity does not seem to be affected. Moreover, a compensatory effect at the postsynaptic level may have occurred due to developmental or functional plasticity for cholinergic responsiveness. In conclusion, the dwarf mouse seems to be a useful model for a better understanding of the influences of growth hormone and thyroid hormones on the development of central cholinergic mechanisms. It also provides the possibility to attempt a functional restoration of the deficient cholinergic neurotransmission and the behavioral disturbances which may be linked to them, by hormone replacemen

ISSN:0360-4012    

DOI:10.1002/jnr.490130308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractBovine cerebrum, including the corpus callosum, and a human oligodendroglioma were investigated by an immunohistochemical technique to determine the distribution of 2′:3′‐cyclic nucleotide 3′‐phosphodiesterase (CNP). Also, three human oligodendrogliomas (ODG) were characterized by an immunoblot procedure to identify a protein(s) with cross‐reacting determinants to CNP and assayed for CNP activity. CNP was localized to oligodendrocytes in the corpus callosum and subcortical white matter and gray matter. Also, nerve fibers appeared to be stained. Further, cells of the human oligodendroglioma were immunostained which were similar in morphology to those cells stained in the bovine cerebrum; however, fewer than 5% of the oligodendroglioma cells were immunostained. Immunoblotting revealed two separate and distinct bands for the three oligodendrogliomas, showing cross‐reactivity to bovine CNP antisera at about 53,000 and 46,000 daltons. Specific CNP activity of the three human oligodendrogliomas ranged from 0.4 to 1.6 μmole of 2′:3′‐cAMP hydro

ISSN:0360-4012    

DOI:10.1002/jnr.490130309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractAnimals fed a diet deficient in thiamine or treated with a drug preventing the utilization of thiamine (thiamine antagonis) exhibited alterations in ligand binding to muscarinic receptors in several brain regions. Using quantitative techniques of receptor autoradiography, an increase in muscarinic receptor binding was demonstrated in such regions as the corpus callosum, lamina VI of the parietal cortex, caudate‐putamen, ventral nucleus of the thalamus, stratum lacunosum moleculare and stratum oriens of the hippocampus, and the hilus of the area dentata. As a result of thiamine deficiency, this increase in muscarinic receptor populations was primarily due to an increase in the binding of the low‐affinity agonist site. In the same experiment, a decrease in muscarinic receptor binding was found in the ventromedial region of the hypothalamus. Thiamine deficiency thus causes an up‐regulation of muscarinic receptor binding in several regions of rat brain while causing a down‐regulation of these same receptors in other brai

ISSN:0360-4012    

DOI:10.1002/jnr.490130310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe effects of surgical denervation, capsaicin, and 6‐Hydroxydopamine pretreatment on the inflammatory response to thermal injury have been investigated in the rat. Surgical denervation and capsaicin pretreatment reduced the cellular and exudative reactions to the injury. 6‐Hydroxydopamine appeared to have a selective effect on the exudative reaction only. The effects of surgical denervation are partly explained by local and systemic effects of the proced

ISSN:0360-4012    

DOI:10.1002/jnr.490130311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY