1,720,961 research outputs found
Carnitine, carnitine acyltransferases, and rat brain function
No full textThe concentrations of free, short chain, and long chain acylcarnitines and the enzyme activities of carnitine acetyltransferase (CAT) and carnitine palmityltransferase (CPT) were studied in different rat brain regions. The fate of tritium-labeled carnitine was studied in different brain regions in vivo after i.p. injection in 3-month-old Sprague-Dawley rats. The tritium counts were particularly high in the hypothalamic region. At 24 h after hydrocortisone injection, a significant increase in counts was observed in the hypothalamus (P < 0.01). A high concentration of total carnitine was found in the hypothalamus (4.00 nmol/mg noncollagen protein) and in other regions such as the spinal cord (1.29 nmol/mg noncollagen protein), cerebellum (1.19), and olfactory tracts (0.66) carnitine concentration was much lower. Carnitine content was proportional to CPT, an inner mitochondrial enzyme. The activity of the enzyme CAT was found to be high in rat hippocampus and hypothalamus. This enzyme in brain may be involved in the transport of acyl groups outside the mitochondria and in the regulation of pyruvate utilization, contributing to acetylcholine synthesis or regulation. © 1982
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Carnitine-palmityltransferase deficiency: clinical variability, carrier detection and autosomal recessive inheritance.
No full textI.F.: 5.973
CLINICAL NEUROLOG
Preliminary study on acetylcarnitine treatment of patients with mental deterioration
No full text15 demented patients aged 56-71 years, who underwent a therapeutic trial with DL or L acetyl carnitine for a period ranging from 1 to 12 months were studied. A number of clinical and electrophysiological parameters (P 300) were evaluated before and after the trial to assess the effect of the drug. In about half of our patients an improvement in intellectual performance and behavior was observed, corresponding to a decrease of P 300 latencies. The mechanisms of action of acetyl carnitine in dementia are discussed
Carnitine and acyltransferase in experimental neurogenic atrophies: changes with treatment
No full textCarnitine level and carnitine palmityl transferase (CPT) activity were investigated in muscles of patients with infantile and juvenile spinal muscular atrophy and polyneuropathies. A significant decrease of both carnitine and CPT was found in the infantile spinal muscular atrophy, but not in the other neurogenic muscle atrophies. These findings were compared with the experimental effect of denervation and reinnervation upon the lipid metabolism in soleus and extensor digitorum longus (EDL) of adult and newborn rats. Twenty-one days after denervation free and total carnitine decreased significantly in both EDL (P<0.001) and soleus (P<0.05) of adult animals. CPT activity was significantly decreased in the soleus 50 days after denervation (P<0.005). Long-term reinnervation restored the level of carnitine fraction and CPT activity. l-carnitine treatment for 21 days restored the level of free carnitine to normal in the soleus of denervated adult animals. Denervation in newborn rats influenced carnitine concentration in soleus and EDL to a lesser extent; the treatment with l-carnitine raised short-chain acylcarnitines in denervated muscles, while reinnervation restored carnitine level within 50 days. © 1984 Springer-Verlag
Myoglobinuria and carnitine palmityltransferase (CPT) deficiency: Studies with malonyl-CoA suggest absence of only CPT-II
No full textA 23-year-old man suffered since adolescence from recurrent myoglobinuria. His ketone body production during fasting was normal. Muscle, liver, and platelet carnitine palmityltransferase (CPT) ranged from 4 to 27% of control by isotope exchange and backward assays. Forward CPT activity was 34% of control in liver, whereas in muscle and platelets it was either normal or absent depending on the experimental conditions. CPT residual activity was studied with malonyl-CoA, a physiologic inhibitor of CPT-I (sensitive fraction) in rat liver mitochondria. In our patient, the insensitive fraction was missing in muscle, liver, and platelets, while the sensitive fraction was increased considerably in the same tissues. Similar results were obtained in platelets of two other patients with CPT deficiency. Increased malonyl-CoA sensitive CPT and decreased mal-onyl-CoA insensitive CPT suggest absence of only the CPT-II isoenzyme in these patients. © 1983 American Academy of Neurology
- …
