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Biomedical subjects

A Guidi

Publications and source records attributed to A Guidi.

29 records · Page 2Linked to original sources
PubMed1989

Effects of a low-phosphorus, low-nitrogen diet supplemented with essential amino acids and ketoanalogues on serum beta-endorphin in chronic renal failure.

The effects of a vegetarian low-protein, low-phosphorus diet supplemented with essential amino acids and ketoanalogues, on the serum beta-endorphin, growth hormone, parathyroid hormone, thyroid hormones (T3 and T4), pituitary TSH and total cortisol were studied in 12 male chronic uremics. beta-Endorphin decreased, as well as growth hormone. Parathyroid hormone and T3 improved significantly, reaching almost normal values. It is hypothesized that the correction of the beta-endorphin excess may account in part for the improvement of some endocrinological and metabolic effects exerted by this dietary treatment. The possible pathophysiological mechanisms which could explain the antiendorphinic action of this treatment in uremic patients are discussed, as well as the possible beneficial endocrine and metabolic effects exerted by the fall in circulating beta-endorphin.

Adolescent↗
PubMedDate not supplied

[Perceptive and semantic selection difficulties and cognitive aging].

This work took place within tipper's negative priming paradigm. In a study with two age groups (young and older adults), Connelly and Hasher have measured the identity negative priming, the location negative priming and the "identity and location" negative priming. They used a simple material (letters). For these authors, the young people showed the negative priming effect in all the conditions, but the older people showed this effect only in location and in "identity and location" conditions, but there was no effect in identity condition. Hence, there is a dissociation between identity and location in the older adults group. Our work replicated the procedure of Connelly and Hasher using material presenting semantic (words) and perceptive selection difficulties. Our results were not consistent with the results of the authors. For the two age groups, the "location" and "identity and location" conditions were computed statistically faster than the "identity" condition, and there was no difference in the reaction times between the "location" and "identity and location" conditions. In the young adults group, even if an identity negative priming was obtained, there was no effect in the "location" and "identity and location" conditions (in comparison with a control condition). This led us to conclude is the existence of a dissociation between identity and location for the young adults. In the older adults group, we obtained positive priming in the "identity and location" condition, and no effect in the other conditions. Moreover, the reaction times in the "location" and "identity and location" conditions were faster than in the identity condition. We think about a dissociation between identity and location in the older group. Our data led us to conclude in the existence of a dissociation between identity and location, not only for the older adults, but also for the young adults. Our conclusion agrees with the explanations given by the authors regarding the neurological system; with the existence of two neuronal pathways, one for the identity and the other for the location. We explain the negative priming effect obtained in the young adults group through controlled inhibition processes, and we explain the positive priming obtained in the older adults group through automatic recuperation processes.

Adolescent↗
PubMedDate not supplied

[Determination of the blood ascorbic acid level after administration of slow-release vitamin C].

PURPOSE: The aim of the present study was to test the effects of a slow releasing form of vitamin C in smokers, because the single high dose previously proposed for smokers gave a transient increase of plasma ascorbate, being rapidly absorbed in the gastrointestinal tract and is rapidly excreted with urine. MATERIALS AND METHODS: In a double-blind placebo-controlled study 18 subjects received both Vitamin C (C-test) and placebo (P-test) in two different periods. During the test-day the subject followed a controlled diet and food Intake was assessed by semiquantitative questionnaire. Peripheral blood sample were collected in fasting conditions, in the morning, before and after 4, 8, 12 and 24 hours from the treatment. Blood sample was collected into EDTA-containing tubes, immediately centrifuged and treated for ascorbate determination, and stored at -70 degrees C until chromatographic analysis. RESULTS: Smokers and nonsmokers were similar for age, height, weight, BMI and for vegetable and fruit consumption. Ascorbic acid level was significantly (p < 0.05) lower than the references level in all subjects, however there were no differences between smokers and non smokers plasma ascorbate concentration increased significantly at T1, T2 and T3 respect to T0 during C test (p < 0.005), whenever remaining higher than T0 was not still significant in T4. CONCLUSION: Our results demonstrate that a slow releasing form of Vitamin C could be useful in clinical pharmacology to increase and to maintain to a constant rate ascorbate level, both in smokers and non smokers with a single daily administration.

Adult↗