摘要:

AbstractSedimentation velocity analyses of the isolated subunits of mouse 7S nerve growth factor (NGF) and their binary complexes have been performed. The 2.5S (β) form of NGF binds 2 α subunits independent of the presence of γ subunits. Two γ subunits are also complexed by 2.5S NGF; however, this interaction is dependent on the presence of a carboxyl terminal arginine residue on the β polypeptide chain. The partial loss of this residue in 2.5S NGF preparations results in a ternary complex(es) with a reduced sedimentation coefficient(s). The two binary complexes formed (α2‐β and β‐γ2) show markedly different pH stability profiles. The α and γ subunits do not form a demonstrable complex, but apparently can interact in the ternary complex to render it more stable than the sum of the α‐β an

ISSN:0360-4012    

DOI:10.1002/jnr.490080204

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe nerve growth factor protein (NGF) isolated from mouse submaxillary gland has been shown to be necessary to the development of vertebrate sensory and sympathetic ganglia. Also, wide ranging alterations in the levels of NGF in the peripheral circulation of humans suffering from a variety of neuropathies have been reported. Many of these reports relied on the use of antibodies directed to the mouse β‐NGF subunit for their quantitation of human NGF antigen. We report here on the lack of crossreaction between antibodies directed to mouse β‐NGF and its human counterpart isolated from placenta at

ISSN:0360-4012    

DOI:10.1002/jnr.490080205

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

年代:1982

数据来源: WILEY

摘要:

AbstractBioassays of factors promoting nerve growth in embryonic ganglia are described. Chick embryo extract evokes fiber outgrowth in both sympathetic and ciliary ganglia explanted into a collagen gel. The response is not suppressed by antibodies directed against mouse nerve growth factor (NGF). Chick embryo extract also supported survival of neurons in both intact and dissociated ganglia. In addition to these non‐NGF activities, preliminary evidence is presented for the release of a NGF‐like factor from cultured iris of the adult ch

ISSN:0360-4012    

DOI:10.1002/jnr.490080206

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe responses of chick embryo retina neurons to the substratum‐bound, neurite‐promoting factor “PNPF” were studied using glia‐free, purified neuronal monolayers. Polyornithine‐coated dishes were exposed before cell seeding to either serum‐containing culture medium (PNPF(−) substratum) or to the same medium supplemented with 25% rat schwannoma conditioned medium, a source of PNPF (PNPF(+) substratum). The dishes were thoroughly rinsed before receiving a suspension of 8 day chick embryo neural retina cells in serum‐free medium.The presence of PNPF on the substratum determined a dramatic increase in the relative frequency of neurite‐bearing cells in the cultures. After 6 hours in vitro PNPF(+) cultures contained 45% neurite‐bearing cells, as compared with 5–7% on PNPN(−) substrata. At 72 hours those values increased to 60% on PNPF(+) and to 40% on PNPF(−) substrata. PNPF(+) cultures also showed longer and/or more highly branched neurites, resulting in the formation of complex neurite networks. Moreover, a cell type characterized by the presence of a very long neurite could be seen on PNPF(+) but not on PNPF(−) substrata.Six hour cultures were used to analyze in more detail the response of retinal neurons to PNPF. Addition of fetal calf serum to the medium determined a concentration‐dependent inhibition of neurite formation on PNPF(+) substrata. On the other hand, pretreatment of PNPF(+) substrata with concanavalin A also blocked the neurite‐promoting effect of the factor. This concentration‐dependent inhibitory effect of concanavalin A could be eliminated by the specific sugar α‐methyl‐D‐mannoside. Wheat germ agglutinin, another lectin known to react with PNPF, did not cause any reduction in the neurite‐promoting activity of this factor. Wheat germ agglutinin showed neurite‐promoting properties of its own in control experiments using PNPF(−) substrata.The results indicate that the target spectrum of PNPF is broader than it was originally thought. Together with other reports from the literature, they also support the perception of neurite development as a cellular a

ISSN:0360-4012    

DOI:10.1002/jnr.490080207

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe effect of mouse nerve growth factor (NGF) on cultured human fetal sensory neurons was assayed by measuring neurite length, density and rate of growth. Addition of NGF increased adhesion of dissociated sensory neurons cultured on collagen coated surfaces. Almost all neurons of 9 to 10 week old fetuses are postmitotic, contain neuron‐specific enolase, (an enzyme linked to differentiation), and require NGF for optimal neurite growth. Sensory ganglia re‐explanted on collagen showed maximal neurite length and density when treated with 1 ng/ml of NGF. Neurite density was reduced considerably in the absence of mouse NGF and was almost abolished by addition of antimouse NGF antibodies. Surfaces coated with the matrix glycoproteins laminin or fibronectin further stimulated neurite growth of ganglia in the presence of NGF. Increasing amounts of matrix proteins could partly compensate for the absence of mouse NGF or the inhibition of NGF activity by antibodies. Stimulation of neurite growth by matrix proteins was time‐dependent, and neurites showed maximum length at 10 days (2 to 3 mm). Neurite growth was more pronounced with laminin than with fibronectin and collagen, and antibodies to laminin suppressed all neurite growth. In the presence of a constant amount of NGF, mean neurite growth reached 26 μm/hr (at 1 day), and was 2.1 and 1.7 times faster on laminin and fibronectin (respectively) than on collagen. Thus, laminin, and to a lesser degree fibronectin, may enhance neurite growth of human sensory neurons in synergy wi

ISSN:0360-4012    

DOI:10.1002/jnr.490080208

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

年代:1982

数据来源: WILEY

摘要:

AbstractA nearly pure neuronal culture from embryonic rat brain (hippocampus) has been established in order to observe individual neurons during their in vitro development. This neuronal culture has been used as a test system for a neurotrophic factor (NTF) which is released into a serum‐free defined medium, presumably by astrocytes, the dominant cell type in a primary glial culture from rat brain. NTF is essential for the development of the hippocampal neurons in cell culture. The number of neurons responding to NTF by neurite extension is highly dependent on the concentration of the factor in the culture medium. The amount of factor in serum‐free glial conditioned medium can be estimated in a rapid (20‐hour) bio

ISSN:0360-4012    

DOI:10.1002/jnr.490080209

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

年代:1982

数据来源: WILEY

摘要:

AbstractSeveral areas of mouse brain (cerebellum, brain stem, and hemispheres) contain levels of nerve growth factor (NGF) detectable by radioimmunoassay. However, this immunoactive NGF is not biologically active in the chick embryo sensory ganglia bioassay. Cerebellum from pcd mice, in which neuronal degeneration elicits a glial response, contains increased amounts of NGF immunoactivity. These results suggest that CNS glia may produce a NGF‐like protein for CNS neuron

ISSN:0360-4012    

DOI:10.1002/jnr.490080210

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

年代:1982

数据来源: WILEY

摘要:

AbstractLong‐term primary cultures of rat sympathetic neurons require NGF for survival and development. The kinetics of the interaction of125I‐NGF with sympathetic neuron cultures suggests the presence of diffusional barriers preventing a determination of true dissociation and association rate constants. Although the observed rate constants do not accurately reflect the microscopic interaction of NGF with receptor, the ratio of the observed rate constants does provide a good estimate of the KD. This value (1 × 10−9M) agrees with earlier steady state measurements of the KD. The association of125I‐NGF with neuronal cultures is temperature‐dependent with internalization and retrograde transport occurring at 37°C. The retrograde transport of125I‐NGF in compartmentalized neuronal cultures is concentration dependent and saturates at about 100 ng/ml (4 × 10−9M). The amount of125I‐NGF accumulated by retrograde transport appears to be increased subsequent to a period of NGF‐starvation. The increase in uptake does not appear to be due to an increase in NGF receptor number since the number of binding sites is not greatly increased

ISSN:0360-4012    

DOI:10.1002/jnr.490080211

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

年代:1982

数据来源: WILEY

摘要:

AbstractSensory neurons isolated from 8‐day chick embryo dorsal root ganglia are shown to be capable of surviving in tissue culture and extending neurites in the absence of nerve growth factor. Survival and formation of neurites by cells cultured in medium supplemented with 2% fetal calf serum is stimulated by insulin, proinsulin or somatemedin MSA. MSA is effective at much lower concentrations (50 ng/ml) than insulin or proinsulin and is suggested to be a physiological regulator of sensory neuronal development. It is demonstrated that at least part of the neuronal population is responsive to both nerve growth factor and insulin homolog

ISSN:0360-4012    

DOI:10.1002/jnr.490080212

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

年代:1982

数据来源: WILEY

摘要:

AbstractA procedure is presented in which a crude extract from selected chick embryo intraocular tissues is submitted to analytical polyacrylamide slab gel isoelectric focusing. The extract contains a protein, ciliary neuronotrophic factor (CNTF) which can be eluted in active form from focused gels in a region occupied by only two protein bands. A “slot” technique is presented in which we demonstrate that the eluted CNTF activity focuses in the very restricted regionbetweenthe two visible bands and is not associated with either band. Silver stain‐densitometry is used to correlate staining intensity with protein concentration and from such an analysis it is concluded that the CNTF protein represents an extremely low proportion of total extract protein and that the minimum CNTF specific activity eluted from gel slices is 106trophic units per mg protein. This one‐step procedure will be used in the future to prepare highly purified CNTF for antibody gen

ISSN:0360-4012    

DOI:10.1002/jnr.490080213

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

年代:1982

数据来源: WILEY