摘要:

WE demonstrate that widespread programmed cell death exists in proliferative regions of chicken optic tectum during early development using a sensitive fluorescent ISEL method (FISEL+) and antibody staining for an antigen in dying cells. Several developmental stages from embryonic day (E) 3 to E18 were examined. FISEL+- positive cells were rare before E7 and between E9 to E12. However massive labeling was observed in the ventricular zone (VZ) between stages E7.5 and E8. At this time extensive cellmigration is underway and many labeled cells were found not only in the VZ (premigratory cells) but also in the intermediate zone and tectal plate (migra-tory cells). Many labeled cells were also found in upper tectal laminae at late developmental stages (E15 and E18).

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

DO the brains of men and women show similar patterns of functional organization for language, or are men more strongly lateralized? We used PET to measure cerebral blood flow (CBF) as men and women read real and nonce verbs, and produced past tense forms. While the overall patterns of reaction time, error, and brain activation were similar, there were also significant sex-related differences in CBF patterns. During the past tense generation tasks, men showed left-lateralized activation while women recruited bilateral perisylvian cortex, confirming differences in functional laterality. During all tasks, women showed higher activation in occipital and/or cerebellar regions, suggesting differences in basic reading strategies. We conclude that sex differences in functional cortical organization exist in the absence of significant behavioral differences.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

SURVIVAL of axotomized adult rat corticospinal neurons (CSN) is supported by glial cell line-derived neurotrophic factor (GDNF). We have evaluated the trophic effects of intrathecally applied GDNF on CSN survival and rat body weight. Body weight reduction is the major side effect of intracerebral neurotrophic factor treatment. GDNF was tested at total doses of 30, 100 and 300 mg over 7 days after axotomy via different application routes: intracerebroventricularly (i.c.v.) and cisternally (cis). Animals injected i.c.v. displayed severe body weight reduction at all doses tested but CSN rescueonly at the highest dose. In contrast, cis-infusion of GDNF promoted CSN survival at all doses and only the highest dose reduced the body weight. These results show that intracisternal, but not i.c.v., GDNF infusion at low doses canpromote CSN survival without negatively affecting rat body weight. This finding may have implications for the clinic use of GDNF.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE lazaroid U-74006F enhances survival of grafted ventral mesencephalic neurons. In this study the intraocular grafting model was used and survival and outgrowth from fetal ventral mesencephalic grafts treated with U-74006F was evaluated in nigrostriatal co-grafts. Fetallateral ganglionic eminence was implanted into the anterior eye chamber and left to mature. Fetal ventral mesencephalon was then implanted and the eyes were treated with U-74006F. The lazaroid treatment enhanced survival of tyrosine hydroxylase (TH)-positive neurons, but did not enhance TH-positive nerve fiber growth into the striatal portions of the co-grafts. However, a marked increasein nerve fiber formation was found within the ventral mesencephalic grafts. Inconclusion, increased cell survival enhanced nerve fiber formation within the ventral mesencephalic portion of the co-graft and not, as expected, in the striatal part.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE neuropathological and immunocytochemical changes in the sheep forebrain following 7 days of microdialysis, using a catheter approved for human use, are described. There was no behavioural dysfunction and light microscopy revealed mild astrogliosis and patchy macrophage infiltration immediately adjacent to the catheter track. The surrounding neuropil was normal. There was one small subcortical haemorrhage (10 × 1.5 mm). These findings are similar to those following microdialysis in rodents and suggest that the risk of significant damage to the human brain is low, that neuropathological changes in the brain around the catheter should not interfere with local brain metabolism, and that the catheter should be affixed in such a way as to minimize movement-induced damage to the brain.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THIS study demonstrated that hyperalgesia resulting from an intraneural injection of the cytokine tumor necrosis factor-alpha (TNF) was prevented by preemptive administration of a single dose of the prosaptide TX14(A) (200 μg/kg). TX14(A) is a synthetic 14-merpeptide with neurotrophic and cytoprotective activities. Efforts to elucidate TX14(A) antagonism of hyperalgesia concentrated on determining the effect of TX14(A) on the up-regulation of the 5 5 kDa TNF receptor (TNFR1) at the nerve injury site. It has been previously shown that TNFR1 expression is upregulated following nerve injury and parallels the display of nociceptive behavior. In our experiments, TNFR1 was decreased at the TNF nerve injection site in TX14(A)-treated rats when compared to vehicle-treated or control peptide-treated rats. Light microscopic evaluation of nerve injury site tissue displayed qualitatively similar neuropathology in both treatment groups during the time of peak hyperalgesia (day 3), but appeared more normal than untreated nerves at day 7 (histological scoring, mean ± s.d., 3.7 ± 0.57 for TX14(A)-treated and 5.67 ± 0.5 for control peptide-treated). These results suggest that TX14(A) decreased nociceptive behavior by attenuating both TNFR1 upregulation and Schwann cell activation in response to TNF injection. This prosaptide neurotrophin may also moderate nerve degeneration or promote regeneration. It is not known whether TX14(A) also acts rostral to the lesion site

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

THE neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) is expressed in sensory neurons. Expression of several neuropeptides is up-regulated in sensory neurons following inflammation. To examine whether also PACAP expression is regulated by inflammation, PACAP expression in L5 dorsal root ganglion (DRG) was determined, usingin situhybridization, after unilateral adjuvant-induced inflammation in the rat paw. At 1 2 h and day 3, but not day 21, the percentage of neurons expressing PACAP mRNA was greater in the innervating L5 DRG. Similarly, PACAP mRNA expression in individual neurons was higher in the innervating L5 DRG at 12 h and day 3, but not day 21. Up-regulated PACAP expression following adjuvant injection suggests a role for PACAP in inflammation.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

We recently reported behavioral improvements following intrastriatal transplantation of cryopreserved cultured human neuroteratocarcinoma-derived cells (hNT neurons) in rats with cerebral ischemia induced by occlusion of the middle cerebral artery. In the present study, the viability and survival of hNT neurons were evaluated immediately prior to the transplantation surgery and at 3 months post-transplantation in ischemic rats. Cryopreserved hNT neurons were routinely thawed, and trypan blue exclusion viability counts revealed 52–95% viable hNT neurons before transplantation. Monthly behavioral tests, starting at 1 month and extending to 3 months post-transplantation, revealed that ischemic animals that were intrastriatally transplanted with hNT neurons (4000) and treated with an immunosuppressive drug displayed normalization of asymmetrical motor behavior compared with ischemic animals that received medium alone. Within subject comparisons of cell viability and subsequent behavioral changes revealed that a high cell viability just prior to transplantation surgery correlated highly with a robust and sustained functional improvement in the transplant recipient. Furthermore, histological analysis of grafted brains revealed a positive correlation between number of surviving hNT neurons and degree of functional recovery. In concert with similar reports on fetal tissue transplantation, we conclude that high cell viability is an important criterion for successful transplantation of cryopreserved neurons derived from cell lines to enhance graft-induced functional effects.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The cytokine leukemia inhibitory factor (LIF)stimulates myoblast proliferationin vitro and vivoand is neurotrophic for motor neurons. In experimentally reinnervated muscle, exogenous. LIF application increases muscle mass through myofiber hypertrophy. The goal ofthis study was to evaluate possible sources of endogenous LIF in human muscle, and whether LIF immunoreactivity (-IR) was detectable in specific myofiber types and/or re-expressed in human denervated muscle. Our study shows that LIF-IR is constitutively detectable in type I myofibers of normal human muscle. In acute and chronically denervated and reinnervated human muscle, LIF-IR is found in all type I myofibers and in addition in some atrophic and almost all angulated atrophic type II myofibers.

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

To assess the action of neurotrophin in human dopaminergic neurons, we studied the immunolocalization of neurotrophins or trks in human substantia nigra pars compacta (SNc). The neuromelanin-containing neurons in the SNc showed immunoreactivities for neurotrophins or trks, suggesting an autocrine/ paracrine regulation. Quantitative analysis revealed that the percentage of those expressing NGF-like immunoreactivity (NGF-LI), BDNF-LI, NT3-LI, trkALI, trkB-LI, or trkC-LI was 66%, 74%, 85%, 66%, 71% or 86%, respectively. The percentage of cells expressing neurotrophins or trks was higher in the medial part than in the lateral part of the SNc. The preferential expression of neurotrophin-trk systems in the medial neurons may, at least partially, explain the differential susceptibility in Parkinson's disease

ISSN:0959-4965    

出版商:OVID    

年代:1998

数据来源: OVID