R. Trotti

Reference values of neuroactive amino acids in the cerebrospinal fluid by high-performance liquid chromatography with electrochemical and fluorescence detection.

Sampling and HPLC analysis procedures for CSF amino acid determinations were evaluated. In order to increase sensitivity, a precolumn derivatization of amino acids by o-phthalaldehyde-mercaptoethanol reagent was used. By using fluorimetric and electrochemical detection in series, positive peak identification can be obtained in a single chromatographic run. It is recommended to analyze freshly collected CSF. Amino acids are stable for short periods over a wide range of temperature, but storage at -80 degrees C is recommended. The CSF samples for the calculation of the reference values were taken from 40 healthy subjects, hospitalized for lumbar disk herniation, placed on the same diet and kept drug-free for at least 1 week. The mean values (mumol/l) and the ranges (in parentheses) were: 0.27 (0.09-0.63), 0.62 (0.18-1.15), 5.32 (3.05-11.50), 6.16 (2.90-13.30), 0.16 (0.03-0.22) for aspartic acid, glutamic acid, glycine, taurine and gamma-aminobutyric acid respectively.

Administration of a dietary supplement (N-oleyl-phosphatidylethanolamine and epigallocatechin-3-gallate formula) enhances compliance with diet in healthy overweight subjects: a randomized controlled trial.

Many studies have found that N-oleyl-ethanolamine (NOE), a metabolite of N-oleyl-phosphatidylethanolamine (NOPE), and epigallocatechin-3-gallate (EGCG) inhibit food intake. The main aim of this study was to evaluate the efficacy of 2 months of administration of an oily NOPE-EGCG complex (85 mg NOPE and 50 mg EGCG per capsule) and its effect on compliance with diet in healthy, overweight people. Secondary end-points of the study were to compare body composition, metabolic parameters, sensation of appetite, depressive symptoms and severity of binge eating. Using a parallel-arm, double-blind, placebo-controlled design, 138 healthy, overweight women (106) and men (thirty-two) were randomly assigned to one of two groups: (1) the treatment group (seventy-one patients: fifty-three females, eighteen males) taking two capsules per day of an oral supplement or (2) the placebo group (sixty-seven patients: fifty-three females, fourteen males). Both groups observed a 3344 kJ/d energy restriction. All parameters were assessed both before onset and after 2 months on the supplement. Dropout was 6 % in the NOPE-EGCG group and 27 % in the placebo group (P < 0.001). The treatment induced a significant weight reduction in both groups ( - 3.28 kg and - 2.67 kg in NOPE-EGCG and placebo, respectively); the weight changes were not significantly different between the groups. NOPE-EGCG treatment improved insulin resistance (P < 0.001), the sensation feelings of fullness (P < 0.05), depressive symptoms (P < 0.004) and severity of binge eating (P < 0.0001).

Increased Erythrocyte Glutathione Peroxidase Activity and Serum Tumor Necrosis Factor-α in HIV-Infected Patients: Relationship to On-Going Prothrombotic State

A condition of oxidative stress, due to perturbation of oxidant/antioxidant balance, has been suggested to play a role not only in the pathogenesis of human immunodeficiency virus (HIV) infection, but also in the promotion of a thrombophilic condition. Because various hemostatic dysfunctions usually considered as risk factors for thrombotic events were reported in HIV infection, this study was undertaken to investigate whether the oxidative phenomenon could promote a prothrombotic state in such condition. Erythrocyte glutathione peroxidase (GSH-Px), the major free-radical scavenger enzyme, and serum tumor necrosis factor-alpha (TNF-alpha) were evaluated in 33 consecutive HIV-infected out-patients and 35 matched HIV-negative healthy controls at a distance of any acute episode. Thrombin generation was explored by measuring the plasma levels of prothrombin fragment 1 + 2 (F1 + 2), whereas fibrin degradation products (D-dimer) and plasminogen activator inhibitor (PAI-1) activity were evaluated as indices of plasmin activity and fibrinolytic derangement. The anticoagulant pathway was investigated by measuring the plasma levels of antithrombin and protein C. Erythrocyte GSH-Px activity and serum TNF-alpha were significantly higher in HIV-infected patients when compared to controls. F1 + 2, D-dimer, and PAI-1 activity were increased in HIV-infected patients by comparison with controls. Normal antithrombin, but decreased protein C, was instead detected in HIV-infected patients. In the latter patients, serum TNF-alpha negatively correlated with both erythrocyte GSH-Px activity and plasma D-dimer. On the other hand, a positive correlation was shown between F1 + 2 and D-dimer and between D-dimer and GSH-Px activity. Furthermore, a trend toward increasing levels of GSH-Px with increasing PAI-1 activity was reported. These findings suggest a relationship between erythrocyte oxidative stress and the hypercoagulable condition during HIV infection.

Endocrine Pancreatic Dysfunction in HIV-Infected Children: Association with Growth Alterations

BACKGROUND The pancreatic endocrine system normally guarantees a quick and efficient response to daily metabolic perturbations, but associated data for human immunodeficiency virus (HIV)-infected patients are lacking. A prospective study was performed to evaluate pancreatic endocrine secretion and its possible association with failure to thrive among HIV-infected children. METHODS Fourteen well-nourished, prepubertal, HIV-infected children (6 boys and 8 girls; age range, 5-11 years), none of whom were receiving protease inhibitors, and 16 clinically healthy sex- and age-matched children formed the patient group and the control group, respectively. At yearly follow-up examinations, insulin, glucagon, C-peptide, and glucose levels were measured; the ratio of insulin to glucose, the ratio of insulin to glucagon, and the homeostasis model assessment (HOMA) index were calculated; the glucagon test was administered; and growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, cortisol, and lipid patterns were evaluated. RESULTS Insulin, glucagon, C-peptide, glucose, and HOMA measurements were significantly higher among patients, compared with control subjects, at all 3 follow-ups performed to date. The glucagon test revealed a normal glycemic response in all the healthy control subjects and a significantly impaired response in 11 patients. A significant correlation emerged between the ratio of insulin to glucagon and the growth velocity of HIV-infected children. CONCLUSION To our knowledge, the present study provides the first evidence of altered pancreatic endocrine secretion and its association with growth failure among HIV-infected children.

Effects of weight loss on erythrocyte membrane composition and fluidity in overweight and moderately obese women.

A previous study showed chemical and physical impairment of the erythrocyte membrane of overweight and moderately obese women. The present study investigated the effects of a low-calorie diet (800 kcal/day deficit for 8 weeks) on erythrocyte membrane properties in 70 overweight and moderately obese (body mass index, 25-33 kg/m(2)) normotensive, nondiabetic women. At the end of dietary intervention, 24.3% of women dropped out, 45.7% lost less than 5% of their initial weight (Group I) and only 30% of patients lost at least 5% of their initial body weight (Group II). Group I showed no significant changes in erythrocyte membrane composition and function. The erythrocyte membranes of Group II showed significant reductions in malondialdehyde, lipofuscin, cholesterol, sphingomyelin, palmitic acid and nervonic acid and an increase in di-homo-γ-linolenic acid, arachidonic acid and membrane fluidity. Moreover, Group II showed an improvement in total cholesterol, low-density lipoprotein cholesterol, glycemia and insulin resistance. These changes in erythrocyte membrane composition could reflect a virtuous cycle resulting from the reduction in insulin resistance associated with increased membrane fluidity that, in turn, results in a sequence of metabolic events that concur to further improve membrane fluidity.

Circadian temporal organization of lipidic fractions in elderly people. Entrainment to the dietary schedule

Background and aims: Changes in some rhythmometric parameters have been reported in the elderly as a consequence of both structural and neurochemical changes occurring in the central nervous system. Since alterations of lipid and lipoprotein metabolism are directly involved in several age-related disorders, the aim of this study was to investigate the circadian temporal organization of some important lipidic fractions (total cholesterol, triacylglycerol, apolipoprotein A1 and B) in physiological aging. Methods: Thirty old hospitalized subjects were synchronized for daily activities, sleeping/waking habits, and time/quality of meals. Twenty-four healthy young individuals served as controls. After an overnight fast, samples were taken beginning at 08:00 every 4 hours until 20:00, and every 2 hours from 20:00 to 04:00. Rhythmometric data were analyzed by single and population mean Cosinor analysis, and by ANOVA; the comparison of the rhythm’s parameters between elderly and young subjects was carried out by the Mesor test and the amplitude-acrophase using Hotelling’s test. Results: Elderly subjects exhibited statistically significant circadian rhythms for total cholesterol (p<0.00002), triacylglycerol (p<0.000001), apo A-1 (p<0.0013), and apo B (p<0.0104). Young subjects also exhibited statistically significant daily fluctuations for total cholesterol (p<0.0003), triacylglycerol (p<0.03), apo A-1 (p<0.002) and apo B (p<0.003). The mean level of apo B rhythm was higher in old subjects than in controls. Conclusions: These data suggest that the circadian temporal organization of lipidic fractions is maintained in physiological aging and underline the importance of the feeding schedule as a powerful synchronizer of the daily lipidic profile.

Biological variability of myoglobin in healthy elderly and younger subjects

To study the effect of age on serum myoglobin more clearly, the analytical, intra-individual and inter-individual components of variation were estimated from duplicate analyses of specimens collected from 18 healthy elderly subjects [ages 74–97 years; 9 men (EM)], and 14 healthy younger subjects [ages 25–31 years; 7 men (YM)] over a period of 6 weeks. The mean values (μg/L) were EM: 53.7; EW: 44.9; YM: 34.2; YW:24.8. Estimated analytical (CVA), intra- (CVI) and inter-individual (CVG) variations as CV% were: CVA: 2.2. CVI: EM: 13; EW: 9.9; YM: 12.4; YW: 9.6. CVG: EM: 37.6; EW: 28; YM: 18.5; YW: 13.4. The data obtained were used to derive the desirable analytical goal for imprecision (i.e., ≤6.5% in EM; ≤4.9% in EW and ≤6.2% in YM; ≤4.8% in YW); inaccuracy (i.e., ≤9.9% in EM; ≤7.7 in EW and ≤5.5% in YM; ≤4.12% in YW); the change required for serial results to be significantly different (i.e., 36% in EM; 28% in EW and 34% in YM; 27.2% in YW), the numbers of specimen collections required to produce a more precise estimate of the homeostatic set point of an individual within 5% (i.e., 26 in EM; 16 in EW and 24 in YM; 15 in YW), and the index of individuality (i.e., 0.34 in EM; 0.35 in EW and 0.67 in YM; 0.71 in YW). This study shows that intra-individual biological variation of myoglobin in healthy elderly subjects is not different from that in young subjects. Inter-individual variation, instead, is greatly influenced by differences in age and sex.

Activation of coagulation and fibrinolysis in HIV-infected patients: relationship to oxidative stress

Abstract Various hemostatic dysfunctions usually considered as risk factors for thrombotic events were reported in HIV infection, even in the absence of clinically-apparent thrombosis and correlation to the progression of the disease. Since oxidative stress has been suggested to promote a procoagulant activity, we carried out a study to investigate whether the apparently perturbed oxidative/antioxidant balance could contribute to an activation of the hemostatic system in HIV infection. For that purpose, 49 consecutive HIV-infected outpatients and 43 matched HIV-negative healthy controls were studied at distance for any acute episode. Plasma levels of prothrombin fragment 1+2 (F1+2), plasminogen activator inhibitor (PAI-1) activity and fibrin degradation products (D-dimer) were evaluated to investigate the degree of the activation of the hemostatic system. Plasma levels of malondialdehyde (MDA), the main end product of lipid peroxidation, and erythrocyte glutathione peroxidase (GSH-Px), a key enzyme for protecting cells against hydroperoxides derivates, were measured to investigate the oxidative/antioxidant balance. Plasma levels of F1+2 and D-dimer well correlated and were shown significantly higher in HIV-infected patients when compared with the controls as was a PAI-activity. The index of peroxidation MDA and the antioxidant molecule GSH-Px was significantly higher in HIV-infected patients when compared to controls. Furthermore, GSH-Px activity correlated with both F1+2 and D-dimer in HIV-infected patients, suggesting a relationship between pertubed antioxidant defenses and activation of the hemostatic system.