摘要:

The pre-imaginal development ofDrosophilamushroom bodies is under the influence of an unknown variable which causes populations of wild-type flies at eclosion to differ in the average number of Kenyon cell fibers. During the first week of adult life the number adjusts to an intermediate level which depends upon the experience of the flies. Under olfactory deprivation or social isolation it reaches a lower level than under favorable rearing conditions (J. Neurogenet., 1 (1984) 113-126). The biochemical learning mutantsdunceandrutabagashow no experience-dependent modulation of fiber number (Fig. 2). In both strains the mushroom bodies of young adults seem to develop abnormally: induncea loss of about 600 fibers is observed, inrutabagafiber number is low at eclosion and does not increase (Fig. 1a). The following model for long-term memory is proposed: in mushroom bodies outgrowth and decay of Kenyon cell fibers occur simultaneously. The fibers randomly form transient synapses onto extrinsic output neurons of the mushroom bodies and receive synapses from modulating neurons. Experience consolidates certain synapses, thus prolonging survival of the respective Kenyon cell fibers and increasing the steady state level of fiber number (Fig. 3).

ISSN:0167-7063    

DOI:10.3109/01677068709167218

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

We used the hippocampal slice to examine extracellular electrophysiological responses to nicotine and the difference in sensitivity to nicotine-induced electrophysiological effects between the DBA and C3H mouse strains. Nicotine enhanced CA1population spikes (PS) evoked by Schaffer collateral stimulation in a concentration-dependent manner (100μM to 3.2 mM). This enhancement was slow to appear, achieving a maximum after 15 min. The enhanced PS was accompanied by the development of epileptiform activity (multiple PS's) at nicotine concentrations≥400μM. Slices from DBA mice were significantly more sensitive than those from the C3H strain to these electrophysiological effects of nicotine. Mecamylamine (400μM) blocked both the nicotine-induced PS enhancement and secondary population spikes in both strains, suggesting the involvement of nicotinic cholinergic receptors.

ISSN:0167-7063    

DOI:10.3109/01677068709167219

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

An infant with propionic acidemia presented at one month of age with hyperammonemic coma. Treatment by two double-volume exchange transfusions did not have an appreciable effect, but hemodialysis led to a substantial reduction of the serum concentration of ammonia on two occasions. Nevertheless, continued therapy with sodium benzoate, arginine-HCl, carnitine and lactulose did not have any observable effect on the blood concentration of ammonia. Treatment with sodium phenylacetate was followed by a reduction in serum concentrations of ammonia to normal levels which were maintained. These observations demonstrate the dramatic reduction in serum concentrations of ammonia that may be obtained in patients with organic acidemia by hemodialysis. They suggest that pharmacologic acylation therapy with phenylacetate may be of lasting benefit in the management of this complication.

ISSN:0167-7063    

DOI:10.3109/01677068709167220

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

In order to identify the genetic locus responsible for familial dementia of the Alzheimer type (DAT), we are studying 10 families in which DAT appears to be inherited as an autosomal dominant trait. Genotypes for a TaqI restriction fragment length polymorphism (RFLP) at the apolipoprotein CII locus were determined for the following groups: affected and unaffected DAT family members, DAT subjects with no family history of the disease, and normal control subjects. The control group included 103 individuals from our study and 123 from the study of Wallis et al. (Hum. Genet., 68 (1984) 286). The frequency of the TaqI fast (F) allele in the affected familial DAT subjects (0.64±0.08) differed significantly from that for the control group (0.39±0.02) (Z = 2.87,P0.40). Subsequently, genotypes were determined for two other polymorphisms at the Apo CII locus: a BanI RFLP and a BglI RFLP. For these two polymorphisms, the allele frequencies for the familial DAT subjects differed from the unaffected control groups but the differences were smaller and not statistically significant. These data suggest a previously unrecognized association between the Apo CII TaqI F-allele and familial DAT.

ISSN:0167-7063    

DOI:10.3109/01677068709167221

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

ISSN:0167-7063    

DOI:10.3109/01677068709167222

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor