Biomedical subjects

G Pastori

Publications and source records attributed to G Pastori.

10 recordsLinked to original sources

PubMed2005

Advanced glycation end products/peptides: an in vivo investigation.

Advanced glycation end products/peptides (AGE/peptides) originate by in vivo enzymatic digestion of nonenzymatically glycated proteins, which are produced by reaction of glucose with primary amino groups present in the protein chain following the Maillard pattern. AGE/peptides are highly reactive species and can interact with tissue and circulating proteins, leading to tissue modification and impaired protein functionality. Serum levels of AGE/peptides are reported to be particularly high in diabetes (in terms of higher production) or in end-stage renal disease (in terms of accumulation). For these reasons, their structural identification is of high interest, giving information on their relationship with the pathological state and allowing the design of possible therapeutic interventions. We report here some preliminary results obtained by liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) and matrix-assisted laser desorption ionization MS (MALDI-MS) investigations carried out on the low-molecular-weight serum peptide fraction from 10 healthy subjects, 10 patients with poorly controlled diabetes, and 10 patients with end-stage nephropathy.

Amines↗

PubMed2000

Diet and overall survival in a cohort of very elderly people.

We conducted a 5-year cohort study among 162 self-sufficient residents in a public home for the elderly in Rome, Italy, to evaluate the association between the consumption of specific food groups and nutrients and overall 5-year survival. We used a validated, semiquantitative food-frequency questionnaire to assess diet at baseline. Individuals consuming citrus fruit at least twice a week had an adjusted risk of dying that was half that of individuals who consumed citrus fruit less than once a week [relative risk (RR) = 0.52; 95% confidence interval (CI) = 0.28-0.95] (with adjustment for gender, age, education, body mass index, smoking status, cognitive function, and chronic diseases). The adjusted RRs of mortality were 0.38 (95% CI = 0.14-1.01) for consumption of milk and yogurt at least three times a week vs less than once a week; 0.21 (95% CI = 0.08-0.35) for moderate consumption of espresso coffee (1-2 cups weekly) vs less than once a week; and 0.35 (95% CI = 0.17-0.69) for > 2 cups a week of espresso coffee vs less than once a week. High levels of intake of ascorbic acid, riboflavin, and linoleic acid were associated with 50-60% decreases in mortality risk. High consumption of meat was associated with a higher risk of mortality (RR = 9.72; 95% CI = 2.68-35.1) among subjects with chronic diseases. Our findings indicate that frequent consumption of citrus fruit, milk, and yogurt; low consumption of meat; and high intake of vitamin C, riboflavin, and linoleic acid are associated with longevity.

Aged↗

PubMed2000

Low temperature-induced changes in the distribution of H2O2 and antioxidants between the bundle sheath and mesophyll cells of maize leaves.

The distribution of antioxidants between bundle sheath and mesophyll cells of maize leaves was analysed in plants grown at 20 degrees C, 18 degrees C and 15 degrees C. The purity of the isolated bundle sheath and mesophyll fractions was determined using compartment-specific marker enzymes. In plants grown at 15 degrees C, ascorbate peroxidase, CuZn-superoxide dismutase (CuZn-SOD) and monodehydroascorbate reductase activities were increased in the bundle sheath cells, and glutathione reductase, dehydroascorbate reductase and monodehydroascorbate reductase activities were enhanced in the mesophyll cells. SOD was absent from the mesophyll of plants grown at 20 degrees C but an Fe-SOD activity was found in the mesophyll of plants grown at 15 degrees C. Foliar Mn-SOD activities were decreased at 15 degrees C compared to 20 degrees C. Catalase was undetectable in the mesophyll extracts of plants grown at 15 degrees C. Ascorbate and glutathione contents were considerably higher in the mesophyll than the bundle sheath fractions of plants grown at 20 degrees C. The ratios of reduced to oxidized forms of these antioxidants were significantly decreased in the bundle sheath, but increased in the mesophyll of leaves grown at 15 degrees C. Foliar H2O2 accumulated at 15 degrees C compared to 20 degrees C. Most of the foliar H2O2 was localized in the mesophyll tissues at all growth temperatures. The differential distribution of antioxidants between leaf bundle sheath and mesophyll tissues, observed at 20 degrees C, is even more pronounced when plants are grown at 15 degrees C and may contribute to the extreme sensitivity of maize to low temperatures.

Antioxidants↗

PubMed1999

Elevated glutathione biosynthetic capacity in the chloroplasts of transgenic tobacco plants paradoxically causes increased oxidative stress

Glutathione (GSH), a major antioxidant in most aerobic organisms, is perceived to be particularly important in plant chloroplasts because it helps to protect the photosynthetic apparatus from oxidative damage. In transgenic tobacco plants overexpressing a chloroplast-targeted gamma-glutamylcysteine synthetase (gamma-ECS), foliar levels of GSH were raised threefold. Paradoxically, increased GSH biosynthetic capacity in the chloroplast resulted in greatly enhanced oxidative stress, which was manifested as light intensity-dependent chlorosis or necrosis. This phenotype was associated with foliar pools of both GSH and gamma-glutamylcysteine (the immediate precursor to GSH) being in a more oxidized state. Further manipulations of both the content and redox state of the foliar thiol pools were achieved using hybrid transgenic plants with enhanced glutathione synthetase or glutathione reductase activity in addition to elevated levels of gamma-ECS. Given the results of these experiments, we suggest that gamma-ECS-transformed plants suffered continuous oxidative damage caused by a failure of the redox-sensing process in the chloroplast.

Journal Article↗

PubMed1998

Spatial resolution threshold in pseudophakic patients with monofocal and multifocal intraocular lenses.

PURPOSE: To compare the spatial resolution threshold in the central visual field of pseudophakic patients with monofocal and multifocal intraocular lenses (IOLs). SETTING: Eye Clinic, University of Trieste, Italy. METHODS: Twenty phakic normal subjects and four groups of 20 pseudophakic patients each, implanted with refractive and diffractive multifocal IOLs (Domilens Progress 1, AMO Array MPC25NB, or Pharmacia 811X) or with monofocal IOLs (Allergan PC43NB), were studied. The spatial resolution threshold in the central visual field was assessed using high-pass resolution perimetry. Measurements were performed adding spherical correction to test the different foci of the IOL. RESULTS: No significant differences between phakic subjects and pseudophakic patients with monofocal IOLs were found. In distance vision, no significant differences between patients with refractive multifocal IOLs and those with monofocal IOLs were found. The group with the diffractive multifocal IOL showed a significantly higher spatial resolution threshold (P = .003). In intermediate vision, the AMO Array group showed a significantly lower spatial resolution threshold than the other groups (P < .01). The best performance at near distance was in the diffractive group, which was statistically significantly different from the other groups (P < .001). CONCLUSION: In the diffractive group, the high spatial resolution threshold in distance vision could be explained by the lower brightness of the principal focus, related to a different light energy division between the foci. In the Domilens group, the high spatial resolution threshold in near vision could be related to the light energy scattered in a large number of foci.

Aged↗

PubMed1998

Role of the ascorbate-glutathione cycle of mitochondria and peroxisomes in the senescence of pea leaves

We investigated the relationship between H2O2 metabolism and the senescence process using soluble fractions, mitochondria, and peroxisomes from senescent pea (Pisum sativum L.) leaves. After 11 d of senescence the activities of Mn-superoxide dismutase, dehydroascorbate reductase (DHAR), and glutathione reductase (GR) present in the matrix, and ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDHAR) activities localized in the mitochondrial membrane, were all substantially decreased in mitochondria. The mitochondrial ascorbate and dehydroascorbate pools were reduced, whereas the oxidized glutathione levels were maintained. In senescent leaves the H2O2 content in isolated mitochondria and the NADH- and succinate-dependent production of superoxide (O2.-) radicals by submitochondrial particles increased significantly. However, in peroxisomes from senescent leaves both membrane-bound APX and MDHAR activities were reduced. In the matrix the DHAR activity was enhanced and the GR activity remained unchanged. As a result of senescence, the reduced and the oxidized glutathione pools were considerably increased in peroxisomes. A large increase in the glutathione pool and DHAR activity were also found in soluble fractions of senescent pea leaves, together with a decrease in GR, APX, and MDHAR activities. The differential response to senescence of the mitochondrial and peroxisomal ascorbate-glutathione cycle suggests that mitochondria could be affected by oxidative damage earlier than peroxisomes, which may participate in the cellular oxidative mechanism of leaf senescence longer than mitochondria.

Journal Article↗

PubMed1997

Pulsatile ocular blood flow variations with axial length and refractive error.

Ocular pulse amplitude (PA) and pulsatile ocular blood flow (POBF) were studied in 80 eyes from 80 subjects with a refractive error between +3.00 and -28.00 dpt using the Langham Ocular Blood Flow System. PA and POBF were correlated with axial length and refractive error using linear regression analysis. A significant correlation (p < 0.001) was found between PA and axial length (r = -0.787), PA and refractive error (r = 0.775), POBF and axial length (r = -0.655) and POBF and refractive error (r = 0.650). Myopic eyes were further divided into subgroups according to axial length, refractive error and fundus oculi characteristics. Each subgroup exhibited a significant reduction in PA (p < 0.001) compared to the control group. POBF reduction was significant in every subgroup except the subgroup with a refractive error lower than 6 dpt and the subgroup with an axial length shorter than 26 mm.

Adult↗

PubMed1996

Age-related ocular blood flow changes.

PURPOSE: Pulsatile ocular blood flow (POBF is influenced by well-known parameters, such as intraocular pressure (IOP), heart rate, scleral rigidity, blood pressure, and posture. Age is also likely to influence POBF strongly. The purpose of this study was to evaluate POBF in relation to age in normal subjects. METHODS: Relevant data were collected from a sample of 105 normal subjects, ranging in age from 10 to 80 years. To measure the effect of age on POBF, the subjects were divided into seven groups of 15 subjects each; the age range of each group spanned one decade, beginning with age 10. POBF and pulse amplitude (PA) were measured in sitting and supine positions and after suction cup application. RESULTS: Using linear regression analysis, there was a significant correlation between PA and age in the supine position (P = 0.012) and after suction cup application (P = 0.002); in the sitting position, there was a borderline level of statistical significance (P = 0.053). In the sitting position, POBF was 819 +/- 212 microliters/minute in the second decade and 630 +/- 194 microliters/minute in the eighth decade. In the sitting position and after suction cup application, but not in the supine position, a statistically significant correlation between POBF decrease and age was found with linear regression analysis (P < 0.001 and P = 0.004, respectively). Using multiple regression analysis, POBF values revealed a significant correlation with age (P < 0.001), but not with systolic and diastolic brachial pressure. Considering all the subjects, analysis of variance for repeated measures highlighted a significant decrease of POBF from the sitting to the supine position and associated with an IOP increase (P < 0.001) without significant changes of PA. After suction cup application, there was a significant reduction of both PA and POBF (P < 0.001). CONCLUSIONS: The data revealed that as age increased, PA decreased in all three series of measurements. POBF decreased with age, and in subjects older than 50 years, the decrease was more evident. These findings are especially noticeable after IOP increase with suction cup. It must be considered that the age-related value of POBF is a fundamental parameter to evaluate correctly the hemodynamic aspects of the pathologies affecting the eye.

Adolescent↗

PubMed1994

Visual and blood flow responses in low-tension glaucoma.

Low or normal-tension glaucoma (NTG) is a rare clinical condition characterized by a glaucomatous cupping of the optic disk associated with the appearance of typical visual field defects, without ocular hypertension. According to several authors, NTG accounts for 5-15% of primary open angle glaucomas (POAG). In our open study we obtained a complete documentation of clinical and instrumental data-tonometric curve, computerized perimetry, pattern electroretinogram, pulsatile ocular blood flow (POBF) and retinography--on 10 consecutive patients (18 eyes) affected by NTG. We found that the NTG patients were similar to the controls as regards arterial systemic pressure and heart rate, but that POBF values were lower in the NTG patients.

Aged↗

PubMed1990

Considerations upon a non-typical anterior ischemic optic neuropathy.

The authors report the clinical history of a patient with bilateral oedema of the optic nerve head, visual field implication, fluorescein-angiographic and electrofunctional result disturbances, but with maintenance of a normal visual acuity. The etiopathogenetic hypothesis are prospected.

Aged↗