摘要:

The mushroom bodies are two characteristically shaped structures of the insect central brain. InDrosophila melanogasterthey contain more fibers in females than in males. Within the first week of adult life the total number of fibers increases by about 15% and decreases again in flies older than 3-4 weeks. The number of mushroom body fibers is significantly reduced in flies kept under social isolation or deprived of their antennal input, but not in flies subjected to visual deprivation.

ISSN:0167-7063    

DOI:10.3109/01677068409107077

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

Embryonic eye primordia were transplanted from the anuran,Xenopus laevis, to the urodele,Ambystoma mexicanum, in order to assess whether retinal axons of one species could grow to appropriate central targets in a distantly related species. To trace the early retinal projections,Xenopuseye primordia were removed, incubated for 20 min in a solution containing [3H]proline, washed, and then transplanted to host axolotl embryos. Genetically eyeless hosts were used in some of the experiments so that theXenopusoptic fibers would not be guided to their targets by the host's own optic nerve projections.Xenopuseyes were usually able to differentiate into small eyes in the axolotl host. Shortly after primary differentiation, the development of these eyes seemed to arrest. Autoradiography on paraffin sections of the central nervous system of the host revealed that in some casesXenopusretinal ganglion cells were indeed able to send axons to the tectum of the axolotl host. This result suggests that the mechanisms of axonal navigation for this particular central projection are evolutionarily conserved.

ISSN:0167-7063    

DOI:10.3109/01677068409107078

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

When extracts of brain from normal and dystrophic chickens were incubated at 30oC under conditions that favored microtubule assembly, the increase in turbidity of the extract from the dystrophic animal was approximately 50% less than the increase in the turbidity of the extract from the normal animal. In developmental studies using age-matched normal and dystrophic chickens this difference in turbidity was observed only with chickens 65 days ex-ovo or older. The extent of microtubule assembly, as determined by a sedimentation methodology, was a linear function of the total protein concentration in the extract and was equal in extracts from normal and dystrophic chickens. In contrast, the total increase in turbidity was much larger than could be accounted for by sedimenting microtubules and varied in a non-linear manner with the total protein concentration. There was no increase in turbidity when brain extracts that were prepared by centrifugation at 100,000gx 40 min were incubated at 30oC. The condensation reaction of the tubulin in these high speed extracts with microtubules was equal in the extracts from normal and dystrophic animals. These studies indicate that a developmentally regulated difference in brain extracts from normal and dystrophic chickens can be demonstrated by turbidimetric methods but this difference is unrelated to the formation of microtubules in these extracts. These studies support the concept that muscular dystrophy is also accompanied by a change in the central nervous system.

ISSN:0167-7063    

DOI:10.3109/01677068409107079

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

Male C57BL/6 and DBA/2 mice were intrahippocampally microinjected with muscimol (0.5μg), given 15 min prior to individual 20-min exploration tests in a novel environment, and compared to saline controls. The GABA agonist reduced various exploratory acts and locomotor activity in strain C57BL/6 and increased the scores in DBA/2. In conjunction with similar opposite effects previously found with intra-hippocampal methylscopolamine and naloxone, these findings suggest that the opioid modulation of the hippocampal cholinergic mechanism which facilitates behavioral responses to novelty in mice is effectuated indirectly through an inhibitory GABAergic system. The functioning of these regulatory systems appears to depend on genotype.

ISSN:0167-7063    

DOI:10.3109/01677068409107080

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

Neuron-specific enolase is readily detected as early as 54 days gestational age in brain extracts from human fetuses and undergoes a rapid increase with developmental maturation of the nervous system. No genetic variants of this enzyme were found among 14 fetal and 120 postnatal specimens, consistent with previous findings of highly restricted variation among glycolytic enzymes.

ISSN:0167-7063    

DOI:10.3109/01677068409107081

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

3-Hydroxy-3-methylglutaric aciduria was found in a newborn infant whose parents are first cousins. The patient presented at 5 days of life with hyperammonemia, hypoglecemia, and metabolic acidosis. There was no ketonuria. Diagnosis was made by analysis of the pattern of organic acids excreted in the urine. A profound deficiency in activity of 3-hydroxy-3-methylglutaryl-coenzyme A lyase was found in cultured skin fibroblasts. The parents had intermediate levels of enzyme activity.

ISSN:0167-7063    

DOI:10.3109/01677068409107082

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

Two Huntington disease (HD) pedigrees are presented which differ according to mean and distribution of the age at onset, the effect of paternal transmission on the age at onset, presence of manic-depressive symptoms, and type of presenting symptoms. Together with previous reports, the data suggest clinical heterogeneity between HD kindreds which may imply some kind of genetic heterogeneity, most likely subsequent mutation at a single HD locus. The possibility of genetic heterogeneity has important consequences, both in research, and in the counseling and care of families and patients with differing manifestations of the disease.

ISSN:0167-7063    

DOI:10.3109/01677068409107083

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

An American-Italian family is described as affected by an autosomal dominant inherited ataxia which meets the clinical diagnostic criteria for Machado-Joseph disease. This disorder no longer appears to be limited to individuals of known Portuguese ancestry.

ISSN:0167-7063    

DOI:10.3109/01677068409107084

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

Twenty-one families with familial Alzheimer disease were ascertained in a dementia clinic and assessed by multiple family interviews. Eight autopsies were reviewed. The age of onset varied from 25 to 85. Seven pedigrees showed evidence of 3 generation transmission. Paternal age of the founders of 4 lines which could be assessed was higher than controls.

ISSN:0167-7063    

DOI:10.3109/01677068409107085

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor