Purification, primary structure, and properties of Euphorbia characias latex purple acid phosphatase.

A purple acid phosphatase was purified to homogeneity from Euphorbia characias latex. The native protein has a molecular mass of 130 ± 10 kDa and is formed by two apparently identical subunits, each containing one Fe(III) and one Zn(II) ion. The two subunits are connected by a disulfide bridge. The enzyme has an absorbance maximum at 540 nm, conferring a characteristic purple color due to a charge-transfer transition caused by a tyrosine residue (Tyr172) coordinated to the ferric ion. The cDNA nucleotide sequence contains an open reading frame of 1392 bp, and the deduced sequence of 463 amino acids shares a very high degree of identity (92-99%) to other purple acid phosphatases isolated from several higher plants. The enzyme hydrolyzes well p-nitrophenyl phosphate, a typical artificial substrate, and a broad range of natural phosphorylated substrates, such as ATP, ADP, glucose-6-phosphate, and phosphoenolpyruvate. The enzyme displays a pH optimum of 5.75 and is inhibited by molybdate, vanadate, and Zn2+, which are typical acid phosphatase inhibitors.

Intracardiac echocardiography in electrophysiology.

Intracardiac echocardiography (ICE) is a recent, invaluable tool which can provide real-time anatomical guidance in electrophysiological procedures. By inserting intravenously an ultrasound probe and advancing it into the heart, various different views can be obtained which allow to better visualize patient anatomy, to guide the placement of electrophysiological catheters, and to detect immediately procedural complications as they occur. In atrial fibrillation ablation, ICE proves particularly useful to achieve a safer trans-septal puncture (especially in the presence of anatomical anomalies of the interatrial septum) and to help to monitor the visualization of the mapping catheters (circular, high density), or the monitoring of the balloons catheter (Cryo, Laser) position. In ventricular tachycardia ablation, on the other hand, ICE allows for continuous correlation between electrophysiological and structural findings (such as wall motion anomalies or changes in echodensity), and helps to ensure correct catheter contact and to position it, particularly around delicate structures such as the aortic cusps. In any procedure, ICE is also useful to immediately detect procedural complications, such as thrombus formation along catheters, or pericardial effusion. Thanks to its real-time morphological information, ICE provides an ideal complement to simple fluoroscopy or to more complex electroanatomic mapping techniques and is set to gain a wider role in a broad range of electrophysiological procedures.

Structural changes and aggregation process of Cu/containing amine oxidase in the presence of 2,2,2'-trifluoroethanol.

Conformational and structural changes of lentil seedlings amine oxidase (LSAO) were studied in the presence of trifluoroethanol (TFE) by spectroscopic and analytical techniques. At TFE concentrations up to 5%, the induction of a structural transition from beta-sheet to alpha-helix and up to 10% TFE a structural transition from alpha-helix to beta-sheet as well as inactivation of the enzyme are observed. At TFE concentrations between 10-35%, LSAO proves to be prone to aggregation and beyond 35% TFE leads to a non-native protein structure with a high alpha-helix content. The obtained results revealed that the aggregation of LSAO is strongly linked to the nature of secondary structures.

Activity and structural changes of Euphorbia characias peroxidase in the presence of trifluoroethanol.

Activity assays, conformational changes and transitional switches between secondary structures of a peroxidase from Euphorbia characias were studied in the presence of trifluoroethanol and in the presence or absence of calcium ions. The addition of trifluoroethanol up to 10-20% first induced a drastic decrease of alpha-helix content followed by an increase of tryptophan fluorescence emission intensity, a progressive re-induction of the formation of alpha-helical elements concomitant with loss of enzyme activity. In the presence of calcium ions, the fluorescence of the enzyme almost remained unchanged in the trifluoroethanol concentration range 5-20%. Further increase in trifluoroethanol concentration led to a protein structure characterized by a progressive re-induction of alpha-helical elements, a remarkable increase of the tryptophan fluorescence and a loss of enzyme activity. These results indicate that calcium ions in Euphorbia peroxidase play an essential role in maintaining the hydrophobic interactions on the protein structure preserving enzymatic activity.

MAO inhibitory activity of bromo-2-phenylbenzofurans: synthesis, in vitro study, and docking calculations.

Monoamine oxidase (MAO) is an enzyme responsible for metabolism of monoamine neurotransmitters which play an important role in brain development and function. This enzyme exists in two isoforms, and it has been demonstrated that MAO-B activity, but not MAO-A activity, increases with aging. MAO inhibitors show clinical value because besides the monoamine level regulation they reduce the formation of by-products of the MAO catalytic cycle, which are toxic to the brain. A series of 2-phenylbenzofuran derivatives was designed, synthesized and evaluated against hMAO-A and hMAO-B enzymes. A bromine substituent was introduced in the 2-phenyl ring, whereas position 5 or 7 of the benzofuran moiety was substituted with a methyl group. Most of the tested compounds inhibited preferentially MAO-B in a reversible manner, with IC50 values in the low micro or nanomolar range. The 2-(2'-bromophenyl)-5-methylbenzofuran (5) was the most active compound identified (IC50 = 0.20 µM). In addition, none of the studied compounds showed cytotoxic activity against the human neuroblastoma cell line SH-SY5Y. Molecular docking simulations were used to explain the observed hMAO-B structure-activity relationship for this type of compounds.

Catalase and antiquitin from Euphorbia characias: two proteins involved in plant defense?

Here we report the cDNA nucleotide sequences of a calmodulin-binding catalase and an antiquitin from the latex of the Mediterranean shrub Euphorbia characias. Present findings suggest that catalase and antiquitin might represent additional nodes in the Euphorbia defense systems, and a multi-enzymatic interaction contributing to plant's protection against biotic and abiotic stresses is proposed to occur in E. characias laticifers.

Distribution and population determinants of gamma-glutamyltransferase in a random sample of Sardinian inhabitants. 'ATS-SARDEGNA' Research Group.

The relation of a number of determinants to serum gamma-glutamyltransferase (GGT) was studied in a random sample of Sardinian inhabitants of 2283 males and 2520 females aged 20-59 years. The aim of the study was to assess the influence of environmental, behavioural and biochemical factors on GGT levels. Mean values were higher in males than in females and increased with age in both sexes. In sex-specific multiple regression analysis, GGT showed a positive association with body mass index (BMI), alcohol use, total serum cholesterol (T-C), HDL cholesterol (HDL-C), triglycerides (TG), apolipoprotein B (ApoB) and age, and a negative one with coffee consumption and physical activity in males, while in females the enzyme was positively associated with BMI, alcohol use, age, T-C, ApoB, TG and cigarette smoking. The negative association between coffee drinking and serum GGT observed in males suggests that coffee may inhibit the inducing effects of other factors, particularly alcohol use, on GGT in the liver. No biological mechanism has been suggested to explain the association of GGT with BMI, age or physical activity. This study confirms the importance of GGT as a strong marker for alcohol use; but a number of variables, ranging from life-style to biological characteristics, are also important determinants of its plasma values in the 'normal' population.

Hypokalaemia after pneumoencephalography.

The changes in plasma electrolytes and blood pH and gases following the insufflation of air into the subarachnoid space for pneumoencephalography were investigated. The only significant change observed was a rapid fall of plasma potassium most evident at 60 minutes. A concomitant reduction of the urinary Na/K ratio supports the possibility that the change observed may be due to the stimulation of aldosterone secretion caused by this procedure, though its rapid occurrence and reversibility indicate that other influences might at least in part be responsible.

Mean levels and distribution of some risk factors for atherosclerosis in Sardinia: the ATS-Sardegna Survey.

Six population samples of randomly chosen men and women aged 20-59 years in the four provinces of the island of Sardinia, for a total of 5,697 individuals (overall participation 55%), were examined to determine the mean levels and distribution of some risk factors for atherosclerosis. A remarkable uniformity of such levels, with some minor exceptions, was found throughout the island. The overall, age-standardized mean levels for the factors considered are as follows (men and women, respectively): total cholesterol (TC) (mg/dl) 204 and 196; LDL-cholesterol (LDL-C) (mg/dl) 131 and 125; apolipoprotein B (ApoB) (mg/dl) (five out of six areas) 112 and 104; HDL-cholesterol (HDL-C) (mg/dl) 48 and 53; triglyceride (TG) (mg/dl) 117 and 89; systolic blood pressure (mmHg) 129 and 128; diastolic blood pressure (mmHg) 81 and 80; body mass index (BMI) [kg/(m)2] 26 and 25; prevalence of smokers (%) 48 and 15; cigarettes per day among smokers 19 and 11. A regular increase with increasing age exists for TC, LDL-C, ApoB, blood pressure (systolic and diastolic) and BMI. Compared to the results of a previous survey eight years earlier, an unfavorable trend is in progress, particularly for TC levels in both sexes and smoking among women.