排序方式: 共有37条查询结果,搜索用时 0 毫秒
1.
E. Benassi G. Besio A. Cupello P. Mainardi A. Patrone M. V. Rapallino L. Vignolo C. W. Loeb 《Neurochemical research》1992,17(12):1229-1233
The i.p. injection in rats of GABA (740 mg/Kg) after sonication with an equal amount of phosphatidylserine (PS) has an antiepileptic effect. The injection of plain GABA has no such an effect. Blood, brain and synaptosomal accumulation of exogenous labeled GABA under the two circumstances are evaluated. In the case of GABA/PS injection there is a higher passage of the exogenous labeled neurotransmitter into the blood and brain nerve endings (synaptosomes). A higher synaptosomal accumulation of the exogenous labeled neurotransmitter is found even when GABA and PS are injected separately. Since these accumulation increases occur at a time when there is the antiepileptic effect, they seem relevant to it. Our interpretation of the chain of the events resulting in the antiepileptic action is that the phospholipid facilitates from the beginning the first passage of the exogenous neurotransmitter form the peritoneum to the blood. Then a higher passage to the brain tissue and eventually to the GABA-ergic nerve endings ensues. The brisker accumulation of the exogenous neurotransmitter in the nerve endings could be at the basis of a more efficient GABA-ergic inhibitory control in the brain. 相似文献
2.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
3.
The modulation of intracellular GABA activated 36Cl– inout permeation across single Deiters' neuron membranes has been studied in a microchamber system. Addition of Mg2+/ATP on the membrane cytoplasmic side reduces strongly the GABA effect as does ATP alone. However, the greatest inhibition of the GABA effect is given by the addition of Mg2+ to the intracellular side buffer: a complete block of the stimulation by GABA of 36Cl– inout permeation. This is interpreted as due to the presence in this case of a constant concentration of exogenous Mg2+ acting together with endogenous ATP in the small cytoplasmic layer on the membrane inner side. The addition of ADP to Mg2+/ATP increases the inhibitory effect of the latter. This is presumably due to an extra increase of ATP, locally under the membrane, due to phosphorylation of ADP by endogenous phosphocreatine. Overall, the data confirm that phosphorylating conditions impair the intracellular GABA action on 36Cl– inout permeation. 相似文献
4.
1. Studies about the permeation of labelled chloride and GABA across single plasma membranes microdissected from vestibular Deiters' neurons have yielded two unexpected results: (a) intracellular GABA stimulates chloride permeation in an asymmetric fashion (efflux being favoured); (b) under certain conditions GABA permeates by a diffusion mechanism in the out in direction across these plasma membranes.2. These two main results have been obtained over many years together with a host of other indications about the fine mechanism of these events. Thus, a picture has emerged of their physiological meaning within the context of the functioning of the GABAA synapses between the Purkinje cells and the Deiters' neurons.3. In short, it is proposed that at these synapses GABA accumulates into the postsynaptic neuron after its release and activation of the postsynaptic receptors. GABA accumulated in the Deiters' neurons is involved in the process of chloride extrusion to build an inward directed electrochemical gradient for chloride. 相似文献
5.
Isolated squid stellate nerves and giant fiber lobes were incubated for 8 hr in Millipore filtered sea water containing [3H]uridine. The electrophoretic patterns of radioactive RNA purified from the axoplasm of the giant axon and from the giant fiber lobe (cell bodies of the giant axon) demonstrated the presence of RNA species with mobilities corresponding to tRNA and rRNA. The presence of labeled rRNAs was confirmed by the behavior of the large rRNA component (31S) which, in the squid, readily dissociates into its two constituent moyeties (17S and 20S). Comparable results were obtained with the axonal sheath and the stellate nerve. In all the electrophoretic patterns, additional species of radioactive RNA migrated between the 4S and the 20S markers, i.e. with mobilities corresponding to presumptive mRNAs. Chromatographic analysis of the purified RNAs on oligo(dT)cellulose indicated the presence of labeled poly(A)+ RNA in all tissue samples. Radioactive poly(A)+ RNA represented approximately 1% of the total labeled RNA in the axoplasm, axonal sheath and stellate nerve, but more than 2% in the giant fiber lobe. The labeled poly(A)+ RNAs of the giant fibre lobe showed a prevalence of larger species in comparison to the axonal sheath and stellate nerve. In conclusion, the axoplasmic RNAs synthesized by the isolated squid giant axon appear to include all the major classes of axoplasmic RNAs, that is rRNA, tRNA and mRNA.Special Issue dedicated to Prof. Holger Hydén. 相似文献
6.
Jane L Wagstaff Jonathan N Pruneda Stefan MV Freund David Komander 《The EMBO journal》2017,36(24):3555-3572
The Ser/Thr protein kinase PINK1 phosphorylates the well‐folded, globular protein ubiquitin (Ub) at a relatively protected site, Ser65. We previously showed that Ser65 phosphorylation results in a conformational change in which Ub adopts a dynamic equilibrium between the known, common Ub conformation and a distinct, second conformation wherein the last β‐strand is retracted to extend the Ser65 loop and shorten the C‐terminal tail. We show using chemical exchange saturation transfer (CEST) nuclear magnetic resonance experiments that a similar, C‐terminally retracted (Ub‐CR) conformation also exists at low population in wild‐type Ub. Point mutations in the moving β5 and neighbouring β‐strands shift the Ub/Ub‐CR equilibrium. This enabled functional studies of the two states, and we show that while the Ub‐CR conformation is defective for conjugation, it demonstrates improved binding to PINK1 through its extended Ser65 loop, and is a superior PINK1 substrate. Together our data suggest that PINK1 utilises a lowly populated yet more suitable Ub‐CR conformation of Ub for efficient phosphorylation. Our findings could be relevant for many kinases that phosphorylate residues in folded protein domains. 相似文献
7.
Tal Burt Savita Dhillon Pooja Sharma Danish Khan Deepa MV Sazid Alam Sarika Jain Bhavana Alapati Sanjay Mittal Padam Singh 《PloS one》2013,8(7)
Background
A public that is an informed partner in clinical research is important for ethical, methodological, and operational reasons. There are indications that the public is unaware or misinformed, and not sufficiently engaged in clinical research but studies on the topic are lacking. PARTAKE – Public Awareness of Research for Therapeutic Advancements through Knowledge and Empowerment is a program aimed at increasing public awareness and partnership in clinical research. The PARTAKE Survey is a component of the program.Objective
To study public knowledge and perceptions of clinical research.Methods
A 40-item questionnaire combining multiple-choice and open-ended questions was administered to 175 English- or Hindi-speaking individuals in 8 public locations representing various socioeconomic strata in New Delhi, India.Results
Interviewees were 18–84 old (mean: 39.6, SD±16.6), 23.6% female, 68.6% employed, 7.3% illiterate, 26.3% had heard of research, 2.9% had participated and 58.9% expressed willingness to participate in clinical research. The following perceptions were reported (% true/% false/% not aware): ‘research benefits society’ (94.1%/3.5%/2.3%), ‘the government protects against unethical clinical research’ (56.7%/26.3%/16.9%), ‘research hospitals provide better care’ (67.2%/8.7%/23.9%), ‘confidentiality is adequately protected’ (54.1%/12.3%/33.5%), ‘participation in research is voluntary’ (85.3%/5.8%/8.7%); ‘participants treated like ‘guinea pigs’’ (20.7%/53.2%/26.0%), and ‘compensation for participation is adequate’ (24.7%/12.9%/62.3%).Conclusions
Results suggest the Indian public is aware of some key features of clinical research (e.g., purpose, value, voluntary nature of participation), and supports clinical research in general but is unaware of other key features (e.g., compensation, confidentiality, protection of human participants) and exhibits some distrust in the conduct and reporting of clinical trials. Larger, cross-cultural surveys are required to inform educational programs addressing these issues. 相似文献8.
9.
Background
The Evidence-Based Practice (EBP) Project has been investigating the implementation of evidence-based mental health practices (Assertive Community Treatment, Family Psychoeducation, Integrated Dual Diagnosis Treatment, Illness Management and Recovery, and Supported Employment) in state public mental health systems in the United States since 2001. To date, Project findings have yielded valuable insights into implementation strategy characteristics and effectiveness. This paper reports results of an effort to identify and classify state-level implementation activities and strategies employed across the eight states participating in the Project.Methods
Content analysis and Greenhalgh et al's (2004) definition of innovation were used to identify and classify state-level activities employed during three phases of EBP implementation: Pre-Implementation, Initial Implementation and Sustainability Planning. Activities were coded from site visit reports created from documents and notes from key informant interviews conducted during two periods, Fall 2002 – Spring 2003, and Spring 2004. Frequency counts and rank-order analyses were used to examine patterns of implementation activities and strategies employed across the three phases of implementation.Results
One hundred and six discreet implementation activities and strategies were identified as innovative and were classified into five categories: 1) state infrastructure building and commitment, 2) stakeholder relationship building and communications, 3) financing, 4) continuous quality management, and 5) service delivery practices and training. Implementation activities from different categories were employed at different phases of implementation.Conclusion
Insights into effective strategies for implementing EBPs in mental health and other health sectors require qualitative and quantitative research that seeks to: a) empirically test the effects of tools and methods used to implement EBPs, and b) establish a stronger evidence-base from which to plan, implement and sustain such efforts. This paper offers a classification scheme and list of innovative implementation activities and strategies. The classification scheme offers potential value for future studies that seek to assess the effects of various implementation processes, and helps establish widely accepted standards and criteria that can be used to assess the value of innovative activities and strategies. 相似文献10.
L. Rönnback E. Hansson A. Cupello M. V. Rapallino J. Zeuchner L. Rosengren 《Neurochemical research》1986,11(2):317-326
Rats were long-term morphine-intoxicated by a fluid-diet model ensuring an equal nutrient intake in morphinized and control rats. Uptake of neurotransmitters and D-ala2-met5-enkephalinamide (Enk) was studied in the particulate fractions (obtained at 10,000g) from well defined brain regions of long-term intoxicated and morphine withdrawn rats. In control animals the accumulation of [3H]glutamate and [3H]-aminobutyric acid (GABA) reached the highest tissue/medium (T/M) ratio values, 30–120, in the regions studied while monoamine T/M values were 2–10. No active uptake of [3H]Enk could be demonstrated. Striatum showed the most evident modifications in neurotransmitter uptake. In this region the equilibrium T/M ratio for [3H]glutamate and [3H]GABA was significantly lower in intoxicated rats versus controls. Moreover, the T/M ratio for [3H]5-hydroxytryptamine (5-HT) was lower, while that for [3H]dopamine (DA) was higher in abstinent rats in comparison with the controls. [3H]glutamate and [3H]GABA uptakes were also significantly lower, respectively, in frontal cortex, hippocampus and brain stem in intoxicated rats, while [3H]5-HT uptake was significantly lower in hypothalamus after morphine withdrawal. The possible involvement of the endogenous opioid system in the etiology of the alterations is discussed. 相似文献