1,720,965 research outputs found
Purification of bacteriocin AS-48 from an Enterococcus faecium strain and analysis of the gene cluster involved in its production
No full textThe cyclic bacteriocin AS-48 has previously been shown to be produced by Enterococcus faecalis strains. A bacteriocin has been purified from an E. faecium strain (E. faecium 7C5), and it has been found to possess molecular mass, cyclization and amino acid sequence typical of bacteriocin AS-48. In addition to the structural gene as-48A, the sequence analysis of the AS-48 gene cluster present in E. faecium 7C5 has revealed the presence of several putative coding regions presumably involved in bacteriocin production and immunity. The results of DNA hybridization assays have indicated that the AS-48 gene cluster and the gene pd78 are present on the same plasmid, possibly the pPD1 plasmid, in E. faecium 7C5
Reduced plasma levels of tyrosine, precursor of brain catecholamines, and of essential amino acids in patients with severe traumatic brain injury after rehabilitation
No full textOBJECTIVE:
To investigate whether levels of plasma tyrosine and tryptophan, precursors of brain catecholamine and serotonin neurotransmitters, respectively, and other essential amino acids (EAA) may return to normal in patients with severe traumatic brain injury (TBI) after 2 months in a hospital rehabilitation center.
DESIGN:
Peripheral plasma concentrations of tyrosine, tryptophan, and other EAAs in subjects with severe TBI, both at admission (44+/-11d postinjury) and at discharge from the center (110+/-15d after acute event) were compared with concentrations in control subjects.
SETTING:
Tertiary care rehabilitation setting in Italy.
PARTICIPANTS:
Ten men (26.6+/-12.6y) with TBI and 6 healthy subjects (controls) matched for age, sex, voluntary loss of body weight, and sedentary lifestyle.
INTERVENTIONS:
Not applicable. Main Outcome Measures: Concentrations of brain neurotransmitter precursor amino acids and of EAA.
RESULTS:
On admission, patients had lower plasma tyrosine, leucine, valine, methionine, and phenylalanine concentrations than did control subjects. The plasma concentrations of tryptophan were similar in the 2 groups. These amino acid abnormalities were still present at discharge.
CONCLUSION:
The levels of plasma tyrosine and many EAA in patients with TBI did not recover by discharge (110+/-15d) from rehabilitation. Plasma tryptophan concentrations were similar in patients and controls
DETECTION OF FRAGMENTS OF BETA2-MICROGLOBULIN IN AMYLOID FIBRILS
No full textA major controversy regarding dialysis related amyloidosis (DRA) is about the presence and the role of truncated forms of beta2-microglobulin (beta2M) in the amyloid fibrils. Whereas Linke et al have reported the presence of proteolyzed forms of beta2M in the amyloid deposits in over 12 cases, other groups have not confirmed this finding. A similar analysis conduced in our laboratory with beta2-fibrils obtained from six patients confirms Linke's data
STRUCTURE AT 1.44 A RESOLUTION OF AN N-TERMINALLY TRUNCATED FORM OF THE RAT SERUM COMPLEMENT C3d FRAGMENT
No full textComplement component C3 plays a key role in the complement-mediated immune defence, and occupies a central position within the complement cascade system. One of its degradation products, C3dg, was purified from rat serum and crystallised in two different crystal forms as N-terminally truncated fragment. Despite the truncation and the lack of a significant portion of the N-terminus as compared to C3d, the structure of the fragment is highly similar to that of recombinant human C3d (Nagar et al., Science 280 (1998) 1277-1281). Structural details of the reactive site have been obtained, suggesting a possible mode of thioester bond formation between Cys-1010 and Gln-1013 and thioester bond cleavage in the transacylation reaction involving His-1126. The truncation at the N-terminus of C3d leads to the exposure of a surface of the molecule that favours dimerisation, so that in both crystal forms, the fragment is present as a dimer, with monomers related by a two-fold axis
Plasma precursors of brain catecholaminergic and serotonergic neurotransmitters in rehabilitation patients with ischemic stroke
No full textOBJECTIVE: To determine levels of plasma amino acid tyrosine and tryptophan, precursors of brain catecholamine and serotonin neurotransmitters, respectively, in rehabilitative patients with ischemic stroke. DESIGN: Controlled, pre-post analysis, consecutive sample. SETTING: Rehabilitation center. PARTICIPANTS: Twenty men with ischemic stroke (age, 68+/-11.3y) consecutively admitted into rehabilitation 15+/-10 days (range, 7-28d) after an acute cerebrovascular insult; 15 healthy sedentary subjects (controls 1); and 13 healthy hypoactive individuals who had recently had knee arthroplasty (controls 2). Both control groups were matched to stroke subjects for age, gender, and body weight. INTERVENTIONS: At 8:00 am, after overnight fasting, venous blood samples were drawn from patients to determine plasma tyrosine and tryptophan levels. A nutritional evaluation, including nitrogen balance, was made. The same procedures were repeated after 45 days of rehabilitation. Amino acid data were compared with those obtained from the controls. MAIN OUTCOME MEASURE: Plasma concentrations of amino acids. RESULTS: Patients with ischemic stroke, on admission, had lower plasma tyrosine concentration than did both controls 1 (P<.0005) and controls 2 (P<.001), but a similar tryptophan level. The plasma content of tyrosine was similar between the 2 control groups. After 45 days of rehabilitation, the stroke patients' tyrosine and tryptophan levels remained virtually unchanged, as did nutritional parameters. Nutritional intakes were adequate to meet body needs but insufficient to correct plasma tyrosine. CONCLUSIONS: Patients experiencing a recent stroke may have low plasma tyrosine levels and, therefore, reduced brain catecholamine formation. It is possible that an imbalance of brain neurotransmitters may occu
Branched-chain amino acids enhance the cognitive recovery of patients with severe traumatic brain injury
No full textTo investigate whether supplementation with branched-chain amino acids (BCAAs) in patients with severe traumatic brain injury (TBI) improves recovery of cognition and influences plasma concentrations of tyrosine and tryptophan, which are precursors of, respectively, catecholamine and serotonin neurotransmitters in the brain. DESIGN: Forty patients with TBI were randomly assigned to 15 days of intravenous BCAA supplementation (19.6g/d) (n=20) or an isonitrogenous placebo (n=20). SETTING: Tertiary care rehabilitation setting in Italy. PARTICIPANTS: Forty men (mean age, 32+/-15 y) with TBI and 20 healthy subjects (controls) matched for age, sex, and sedentary lifestyle. INTERVENTION: Supplementation with BCAAs. MAIN OUTCOME MEASURES: Disability Rating Scale (DRS) and plasma concentrations of BCAAs, tyrosine, and tryptophan. RESULTS: Fifteen days after admission to the rehabilitation department, the DRS score had improved significantly in both the placebo group (P<.05 vs baseline) and in the BCAA-supplemented group (P<.01 vs baseline). The difference between the 2 groups was significant (P<.004). Plasma tyrosine concentration improved in the group given BCAA supplementation, and tryptophan concentration increased in patients receiving placebo. CONCLUSIONS: Supplemental BCAAs enhance the retrieval of DRS without causing negative effects on tyrosine and tryptophan concentratio
Antidepressive-like effects and antioxidant activity of green tea and GABA green tea in a mouse model of post-stroke depression
No full textGrowing evidence suggests that oxidative stress plays a role in the development of chronic diseases such as cardiovascular disease and some psychiatric disorders. Tea consumption exerts beneficial effects against damage induced by cerebral ischemia-reperfusion in ischemic stroke and depressive symptoms in depression. The aim of this study was to evaluate, in vivo, the protective activity of green tea (GT) and GABA green tea (GGT) against post-stroke depression (PSD), a common consequence of stroke
Increased skeletal muscle amino acid release with light exercise in deconditioned patients with heart failure
No full textThis study shows that, during light exercise, untrained patients with Chronic Heart Failure (CHF) release a number of muscle amino acids, suggesting a possible abnormal muscle amino acid metabolism. It is conceivable that repeated daily-life physical activities by untrained CHF patients may contribute to a negative nitrogen balance and to muscular wastin
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
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