摘要:

AbstractImmunoblot techniques and immunohistochemistry have been used to investigate epitopes shared by α‐melanocyte‐stimulating hormone (α‐MSH) and the 150‐kD neurofilament protein (NF150). Three anti‐α‐MSH antisera (namely 31H2T, 4394, and M5) from a total of 12 sera were found to react with NF150. The three crossreacting sera are different in their binding properties to peptide fragments related to α‐MSH, suggesting that at least two distinct epitopes are shared by NF150 and α‐MSH. The only known sequence common to NF150 and α‐MSH, the N‐terminal Ac‐S‐Y residues, appears to be essential for binding of sera 31H2T and 4394. However, the binding of antiserum M5 involves other, currently unknown, similarities between NF150 and α‐MSH. This is shown by the binding of M5 to peptides such as ACTH(4–10), which do not contain the N‐terminal Ac‐S‐Y sequence. Binding of M5 to tobacco mosaic virus coat protein (TMV‐coat protein), which is homologous with α‐MSH and NF150 in its Ac‐S‐Y residues, was negligible. The peptide structures that are recognized by M5 have previously been shown to exert neurotrophic activity. The data are discussed in the light of the hypothesis that similarity between NF150 and α‐MSH, as illustrated by binding to M5, may be significant

ISSN:0360-4012    

DOI:10.1002/jnr.490160402

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

年代:1986

数据来源: WILEY

摘要:

AbstractMonoclonal antibodies that immunoprecipitate human monoamine oxidase (MAO) A or human MAO B, but not the corresponding mouse enzymes, were used to assay for the presence of immunoprecipitable MAO A or MAO B (presumably coded by the respective human genes) in mouse‐human hybrid somatic cell lines containing small numbers of human chromosomes. The results were as follow: (1) Extracts of a human lymphoblastoid x mouse hepatoma hybrid line that retained the human X chromosome contained immunoprecipitable MAO B, while a similar hybrid line that contained the same human chromosomes, except for the human X, did not. (2) Extracts of a human fibroblast x mouse neuroblastoma hybrid cell line, whose human chromosomal material consisted solely of the X, contained both immunoprecipitable MAO A and MAO B. Extracts of a related hybrid line, whose human chromosomal material consisted solely of an autonomous fragment and a fragment translocated to a mouse chromosome, contained immunoprecipitable MAO A. However, the level of immunoprecipitable MAO B activity in extracts of this hybrid was low or undetectable. (3) Among extracts of 33 human fibroblast x mouse hepatoma hybrids that had been selected for expression of the X‐linked human enzyme HPRT, 60% contained immunoprecipitable MAO B. This figure was comparable to the 58% that expressed the X‐linked human isozyme for glucose‐6‐phosphate dehydrogenase (G6PD). When 11 of these hybrid lines, which contained immunoprecipitable MAO B and human HPRT, were selected for loss of HPRT, all lost immunoprecipitable MAO B in addition to HPRT.These data demonstrate that genes controlling the expression of MAO A and MAO B, which can be immunoprecipited with the human‐specific monoclonal antibodies, are located on the human X chromosome. Properties of the immunological epitopes recognized by the monoclonal antibodies suggest that the X‐linked genes detected in this study are probably structural genes fo

ISSN:0360-4012    

DOI:10.1002/jnr.490160403

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

年代:1986

数据来源: WILEY

摘要:

AbstractAndrogens and estrogens have been implicated in the activation of a variety of sexually‐dimorphic, hormone‐dependent behaviors in the adult zebra finch. In the present report, several biochemical characteristics of two putative sex steroid receptors, androgen‐ and estrogen‐binding activities, were determined by DNA‐cellulose chromatography in brain tissues from these birds. High‐affinity, limited‐capacity receptors for androgens and estrogens were found in cytosolic extracts of telencephalon, diencephalon‐mesencephalon, and metencephalon‐myelencephalon from adult male and female zebra finches. Androgen‐binding activity reproducibly adhered to DNA‐cellulose and was eluted within the 110‐150 mM NaCl region of a linear salt concentration gradient. Estrogen receptors adhered to DNA‐cellulose and exhibited elution maxima between 170 mM and 210 mM NaCl. Collectively these data indicate that brain regions of zebra finches contain steroid receptors that are similar to those found in the brains of other vertebrates and that their biochemical properties are similar in males and females. Quantitatively, males consistently exhibited higher androgen binding than females in both anterior and posterior telencephalic areas. Females treated with estradiol immediately after hatching exhibited adult levels of androgen binding corresponding to those detected in males. Masculinization of the androgen receptor system by early ster

ISSN:0360-4012    

DOI:10.1002/jnr.490160404

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

年代:1986

数据来源: WILEY

摘要:

AbstractBrain fractions of adult control (+ / +) and shiverer (Shi/Shi) mice were investigated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblotting. Immunostaining with specific antisera against rat brain myelin‐associated glycoprotein (MAG) was detected at about the 96‐kD region of gels in electrophoresed samples of the total homogenate, low‐speed supernatant fraction, and low‐ and high‐speed sedimentable portions of brain from +/+ mice. Reduced immunostaining was observed in the corresponding samples of brain fractions from Shi/Shi mice. The cerebrum, cerebellum, and medulla of +/+ and Shi/Shi mice were examined immunocytochemically for MAG on paraffin‐embedded sections. Periaxonal immunostaining for MAG was observed in all the regions and the highest concentrations were in the corpus callosum, in the central cores of cerebellar folia, and in the medulla. Patterns of distribution were similar in +/+ and Shi/Shi mice, although the density of immunostaining around individual axons and the number of immunostained axons were significantly reduced in Shi/Shi mice. In addition, the three brain regions of Shi/Shi mice exhibited oligodendrocyte‐like cells that contained immunostaining for MAG in the cytoplasm and periphery of their perikarya. This type of immunostained cell was not observed in +/+ mice. In this study, immunoblotting with brain fractions and immunocytochemistry revealed strong evidence for reduced concentrations of MAG in the CNS of Shi/Shi mice compared to control mice. In addition, there is immunocytochemical evidence for abnormal accumulation of MAG in perikarya of oligodendroglial‐like cells, suggesting the possibility of a transport block for myelin proteins in

ISSN:0360-4012    

DOI:10.1002/jnr.490160405

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

年代:1986

数据来源: WILEY

摘要:

AbstractExperimental autoimmune encephalomyelitis (EAE) in the Lewis rat is characteristically a monophasic paralytic disorder. Recovered rats are thereafter immune to EAE induced by injection of guinea pig basic protein (GP‐BP) in complete Freund's adjuvant (CFA), but they are still susceptible to EAE induced by an encephalitogenic T‐lymphocyte line (BP‐1). Induction of active EAE or injection of a sublethal dose of activated BP‐1 cells resulted in a monophasic episode of EAE, followed by recovery of normal neurologic function. Repeated challenges with activated BP‐1 cells, however, induced unremitting neurologic signs marked by loss of tail tonicity and incontinence, which persisted for more than 6 months. Histologically, the spinal cord of affected rats revealed attenuation of MBP staining (demyelination) and moderate‐to‐extensive gliosis associated with increased size of intervening spaces. Inflammatory cell lesions, however, were notably absent. Biophysical analysis of isolated spinal cord myelin from affected rats demonstrated a distorted distribution in subfraction densities and the appearance of extra‐myelin proteins in the light myelin subfraction. Immunologically, chronically affected animals were unresponsive to the encephalitogenic determinant on GP‐BP, although other BP determinants elicited strong delayed type hypersensitivity (DTH) reactions in rats immunized initially with GP‐BP in CFA. These data show that ongoing neurologic dysfunction can be induced in the Lewis rat by a GP‐BP specific T‐lymphocyte line; they suggest that unremitting clinical signs can persist in the absence both of inflammatory lesions in the CNS and of pronounced immunologic responsiveness to the encephalitogen

ISSN:0360-4012    

DOI:10.1002/jnr.490160406

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe mutant mouse, wobbler, possesses a recessively inherited degeneration of motoneurons and other ventral horn cells in the cervical spinal cord, and therefore it has been proposed as an animal model of human motoneuron disease. Affected mice have been identified by behavioral tests that also determined the extent of the motor deficit. The results from these tests were combined and used to define distinct stages of the disease process that could then be correlated histochemically with the amount of acetylcholinesterase (AChE) staining in the cervical spinal cord. AChE is used as a marker for cholinergic neurons and is known to hydrolyze the neuropeptide modulator substance P (SP). SP, a peptide neuromodulator of primary afferent transmission in the dorsal horn, excites motoneurons in the ventral horn, and may posses secondary frnctions in neuronal maintenance. Therefore, the levels of immunoreactive (IR) SP and AChE were examined in an attempt to determine the possible interaction between these factors in motoneuron degeneration.By enzyme histochemistry, the cervical spinal cord, taken from wobbler mice at behaviorally identified stages of the motor deficit, exhibited decreased levels of AChE throughout the ventral horn. The decrease detected in the AChE staining intensity was linear and correlated with the decrease in the number of AChE‐positive cells in the ventral cervical spinal cord, as the motor deficit progressed. Presumably, the continual decrease in AChE staining represents the degeneration of cholinergic perikarya and neuronal processes in the ventral horn as the motoneuron disease proceeds.At two well‐established stages of the motor deficit, the amount of immunoreactive SP increased in the ventral horn compared with the control mice. The elevated levels of immunoreactive SP suggest sprouting may have occurred preceding, or in response to, the motoneuron degeneration. Several additional hypotheses are discussed in respect to phenomena that might contribute to the increase of immunoreactive SP in the degnerating ventral horn of the wobbler mo

ISSN:0360-4012    

DOI:10.1002/jnr.490160407

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe cytopathic effects caused by Theiler viruses to myelinated organotypic spinal cord cultures was studied by light and electron microscopy. Heavily myelinated cultures, 2–3 weeks in vitro were infected with WW and GD VII viruses. Mock infection served as control. On light microscopy cytopathic effects and demyelination become evident about 16–17 hr after infection. Demyelination observed in WW virus‐infected cultures was much more pronounced than in cultures infected with GD VII viruses. The myelin in mock‐infected cultures remained undamaged.Electron microscopy revealed that in control cultures cells were intact, exhibiting numerous synapses and a network of axons enwrapped by multilayered myelin sheaths. Virus‐infected spinal cord slices showed that a more severe cytotoxicity was caused by GD VII virus than by WW virus. The cytopathology included accumulation of cytoplasmatic vacuoles, margination of chromatin, synapse and cell disintegration, and various degrees of demyelination. Several GD VII virions were observed, arranged in crystalline arrays, mainly in electron‐opaqe cells, but not within axons. WW virions on the other hand were only occasionally

ISSN:0360-4012    

DOI:10.1002/jnr.490160408

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

年代:1986

数据来源: WILEY

摘要:

AbstractA therapeutic role for naloxone during stroke has been suggested, but a neurochemical site of action remains to be determined. Previous work with the geerbil cerebral cortex has shown that either bilateral secondary ischemia (60‐min occlusion of the carotid arteries followed by 40‐min reflow) or unilateral primary ischemia (permanent ligation of one carotid artery for 6 hr in symptomatic animals) produced deficits in both Na+, K+‐ATPase (EC 3.6.1.3) activity and various parameters of activation of adenylate cyclase (EC 4.6.1.1). Pretreatment of gerbils with either naloxone or morphine failed to ameliorate or exacerbate, respectively, the neurological signs of ischemia; however, morphine did reduce mortality. Infusion of naloxone prior to ischemia afforded varying degrees of protection to forskolin, GTP analogs, and NE (norepinephrine) activation of adenylate cyclase, as well as to Na+, K+‐ATPase (bilateral ischemia only). Similarly, morphine inhibited damage to basal activity of adenylate cyclase and to stimulation by NE, forskolin, and Gpp (NH)p (5′‐guanylyl imidodiphosphate). Under in vitro conditions morphine increased the basal activity of adenylate cyclase but reduced responses to NE and forskolin. Furthermore, morphine injected into control gerbils elevated basal‐ and forskolin‐elicited activities but reduced the activation of adenylat

ISSN:0360-4012    

DOI:10.1002/jnr.490160409

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe coupling ratio betwen sodium and GABA or the GABA analog, (RS)‐nipecotic acid, in neuronal and glial uptake of GABA or nipecotic acid was investigated as a function of the morphological differentiation of these cell types in primary cultures. Both in neurons and astrocytes a high‐affinity uptake of GABA and nipecotic acid was observed ragardless of the degree of differentiation. The values of Kmwere essentially identical in undifferentiated and differentiated cells. On the other hand, Vmaxwas significantly increased both in 10‐day‐old neurons compared to 1‐ and 3‐day‐old neurons and in astrocytes treated with dBcAMP compared to untreated cells, i.e., Vmaxincreased as a function of differentiation in both cell types. In neurons as well as in astrocytes the morphological differentation resulted in an alteration in the coupling ratio between sodium and GABA. From calculated Hill coefficients it could be deduced that the coupling ratio between sodium and GABA was changed from 1 to 2 during differentiation. Similar results were obtained for (RS)

ISSN:0360-4012    

DOI:10.1002/jnr.490160410

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

年代:1986

数据来源: WILEY

摘要:

AbstractExperimental alteration in the restricted permeability of the blood‐brain barrier to polar, blood‐borne molecules is often quantitated in the rat with use of14C‐sucrose or3H‐mannitol delivered as a test substance into the circulation. The underlying principle is to relate the quantity of saccharide that has permeated into brain parenchyma, after an arbitary time period, to some index of the circulating tracer level. This study indicates that to correct the radioactivity level in the brain tissue for intravascular tracer, it is an erroneous practive to estimae the latter as the poduct of tissue blood volume and the tracer concentration measured in a systematic blood sample. Dissected brain tissue was found to have a lower hematocrit and thereby larger plasma/tracer compartment per unit blood volume than femoral arterial blood. It is further shown that, although commercially supplied stocks of14C‐sucrose or3H‐mannitol may contain only small quantities of radioactive impurities, their inclusion in injectates and preferential uptake into brain may cause significant overestimation of permeability to the parent tracer. It is also confirmed that magnitude of permeability‐area (PA) products for permeation of purified sucrose or mannitol into brain varies inversely with the length of time allotted for tracer circulation in the bloodstream. This finding is at variance with the assumptions of a two‐compartment (plasma/brain) diffusion model underlying such measurements and supports a recently published model for blood‐to‐brain transfer based on multiple uptake compartments in brain parenchyma. The factors compromising PA values published from several laboratories that had been attributed to genetic differences

ISSN:0360-4012    

DOI:10.1002/jnr.490160411

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

年代:1986

数据来源: WILEY