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P Preziosi

Publications and source records attributed to P Preziosi.

At least 91 records · Page 5Linked to original sources
PubMed1997

The release of immunoreactive interleukin-1 beta from rat hypothalamic explants is modulated by neurotransmitters and corticotropin-releasing hormone.

Both constitutive and inducible interleukin-1 (IL-1) gene expressions have been described in the central nervous system, the former being associated with immunoreactive IL-1 neurons in human and rat hypothalami. While most studies have focused on the role of IL-1 as a mediator of pathological events in the brain, the cytokine of neuronal origin might also be involved in the regulation of physiological processes. In this study we used a previously validated technique to investigate the effects of classical neurotransmitters and the hypophysiotropic peptide corticotropin-releasing hormone (CRH) on the release of immunoreactive (ir) IL-1 beta from acute rat hypothalamic explants. We found that basal irIL-1 beta secretion is significantly inhibited by acetylcholine and histamine and increased by dopamine, while dexamethasone, IL-4 and IL-10 have no effect. Moreover, cytokine release is dose-dependently increased by CRH. Such effects of the neurotransmitters and CRH are observed in short-term incubation experiments, indicating that a pre-formed pool of hypothalamic IL-1 beta is involved. These findings also suggest that the interaction between IL-1, neurotransmitters and neuropeptides might play a role in the physiological regulation of such processes as body temperature, food intake and the control of hypothalamic-hypophyseal axes.

Acetylcholine↗
PubMed1997

Prevalence of vitamin D insufficiency in an adult normal population.

The vitamin D status of a general adult urban population was estimated between November and April in 1569 subjects selected from 20 French cities grouped in nine geographical regions (between latitude 43 degrees and 51 degrees N). Major differences in 25-hydroxyvitamin D (25(OH)D) concentration were found between regions, the lowest values being seen in the North and the greatest in the South, with a significant 'sun' effect (r = 0.72; p = 0.03) and latitude effect (r = -0.79; p = 0.01). In this healthy adult population, 14% of subjects exhibited 25(OH)D values < or = 30 nmol/l (12 ng/ml), which represents the lower limit (< 2 SD) for a normal adult population measured in winter with the same method (RIA Incstar). A significant negative correlation was found between serum intact parathyroid hormone (iPTH) and serum 25(OH)D values (p < 0.01). Serum iPTH held a stable plateau level at 36 pg/ml as long as serum 25(OH)D values were higher than 78 nmol/l (31 ng/ml), but increased when the serum 25(OH)D value fell below this. When the 25(OH)D concentration became equal to or lower than 11.3 nmol/l (4.6 ng/ml), the PTH values reached the upper limit of normal values (55 pg/ml) found in vitamin D replete subjects. These results showed that in French normal adults living in an urban environment with a lack of direct exposure to sunshine, diet failed to provide an adequate amount of vitamin D. It is important to pay attention to this rather high prevalence of vitamin D insufficiency in the general adult population and to discuss the clinical utility of winter supplementation with low doses of vitamin D.

Adult↗
PubMed1997

Evidence that carbon monoxide stimulates prostaglandin endoperoxide synthase activity in rat hypothalamic explants and in primary cultures of rat hypothalamic astrocytes.

Carbon monoxide (CO) shares with nitric oxide (NO) the ability to modulate the release of hypophysiotropic peptides from rat hypothalamic explants. While both gases are believed to act as neural messengers in the brain via the activation of soluble guanylyl cyclase, the latter is almost undetectable in the rat hypothalamus. NO has been shown to exert some of its biological actions through the modulation of prostaglandin endoperoxide synthase (PGHS) activity. We have, therefore, investigated whether CO also can use PGHS as a signaling pathway in the hypothalamus. Endogenous CO is produced in equimolar amounts with biliverdin (BV) by the catabolism of hemin through heme oxygenase (HO). Hemin, two inhibitors of HO, zinc-protoporphyrin-9 (ZnPP9) and tin-mesoporphyrin-9 (SnMP9), ferrous hemoglobin (Hb), indomethacin and dexamethasone (DEX) were used as pharmacological tools. Prostaglandin E2 (PGE2) released from rat hypothalamic explants or primary cultures of hypothalamic astrocytes was taken as a marker of PGHS activity. It was found that: (1) hemin evokes an increase in PGE2 release from hypothalamic explants; (2) this effect is counteracted by ZnPP9, SnMP9, Hb and indomethacin; (3) the metallo-porphyrins and indomethacin, but not Hb, are also able to inhibit basal PGE2 release from hypothalamic explants; and (4) dexamethasone does not inhibit, and even potentiates, the stimulatory effect of hemin on PGE2 release from hypothalamic astrocytes. The evidence presented here suggests that the catabolism of endogenous or exogenously added hemin is associated with an increase in PGE2 production in the rat hypothalamus. This effect can be attributed to the formation of CO, since the other end-product of HO, BV, does not enhance PGE2 release. Thus, at least some of the biological effects of CO at the hypothalamic level might be mediated by the activation of the PGHS pathway.

Animals↗
PubMed1997

Involvement of vasoactive intestinal polypeptide in nicotine-induced relaxation of the rat gastric fundus.

1. Nicotine-induced relaxation and release of vasoactive intestinal polypeptide (VIP)- and peptide histidine isoleucine (PHI)-like immunoreactivity (LI) were measured in longitudinal muscle strips from the rat gastric fundus. 2. Under non-cholinergic conditions (0.3 microM atropine), nicotine (3-300 microM) produced concentration-dependent relaxations of the 5-hydroxytryptamine (3 microM)-precontracted strips. Under non-adrenergic non-cholinergic (NANC) conditions (0.3 microM atropine + 1 microM phentolamine + 1 microM nadolol), relaxations induced by sub-maximal nicotine concentrations (10 and 30 microM) were significantly smaller, while that produced by the highest concentration used (300 microM) was similar to that seen under non-cholinergic conditions. 3. Re-exposure to the same nicotine concentration 1 h later induced smaller relaxations, indicating desensitization. The reductions seen in the second responses were proportional to the concentration used. 4. Under non-cholinergic conditions, the relaxant response to 30 microM nicotine was abolished by hexamethonium (100 microM) and significantly reduced by tetrodotoxin (TTX, 3 microM). The TTX-resistant component was not observed under NANC conditions. 5. NANC relaxation induced by 30 microM nicotine was significantly reduced by a specific anti-VIP serum (approximately 35% less than that seen with normal rabbit serum). 6. Nicotine (30-300 microM) caused significant, concentration-dependent increases in the outflow of VIP- and PHI-LI from the strips; these effects were also diminished with re-exposure. The increases in both types of immunoreactivity evoked by nicotine (300 microM) were abolished by hexamethonium (300 microM), TTX (3 microM) and a calcium-free medium. 7. These findings indicate that VIP and possibly PHI are involved in NANC relaxation of the rat gastric fundus induced by nicotine.

Animals↗
PubMed1997

Serum beta-carotene and vitamin C as biomarkers of vegetable and fruit intakes in a community-based sample of French adults.

Relatively high intakes of vegetables and fruit and relatively low intakes of fat are associated with lower rates of heart disease and many types of cancer. Biomarkers for vegetable and fruit consumption are most useful when applicable across different ages, body weights, diets, and varying patterns of fat intake. This study examined two biomarkers, serum concentrations of beta-carotene and vitamin C, as a function of anthropometric, dietary, and lifestyle factors in a community-based sample of French adults. The interview-based dietary-history method was used to assess dietary intakes of 361 males and 476 females aged 18-94 y resident in the Val-de-Marne district southeast of Paris. Serum beta-carotene was quantified by HPLC and vitamin C was measured by using an automated method. Serum beta-carotene and vitamin C concentrations were positively associated with vegetable and fruit intakes and were negatively linked to the consumption of energy, alcohol, and fat. Multiple-regression analyses showed that serum beta-carotene concentration was predicted by fruit and vegetable intakes but was inversely associated with body mass, energy and alcohol intakes, and tobacco use. Serum vitamin C concentration was positively associated with fruit consumption but was negatively associated with age, body mass, and tobacco use. Serum beta-carotene and vitamin C concentrations are useful biomarkers of vegetable and fruit consumption in the French diet. However, other dietary and lifestyle factors also have a significant effect on circulating concentrations of these antioxidant micronutrients.

Adolescent↗
PubMed1997

Effect of iron supplementation on the iron status of pregnant women: consequences for newborns.

We studied the effect of iron supplementation on the iron status of mothers and on biochemical iron status and clinical and anthropometric measures in their infants. The subjects were 197 pregnant women selected at 28 wk +/- 21 d of gestation at a mother-and-child health center in Niamey, Niger. Ninety-nine women received 100 mg elemental Fe/d throughout the remainder of their pregnancies and 98 received placebo. The prevalence of anemia and iron deficiency decreased markedly during the last trimester of pregnancy in the iron-supplemented group but remained constant in the placebo group. Three months after delivery, the prevalence of anemia was significantly higher in the placebo group. At delivery, there were no differences between the two groups in cord blood iron variables. Three months after delivery, serum ferritin concentrations were significantly higher in infants of women in the iron-supplemented group. Mean length and Apgar scores were significantly higher in infants with mothers in the iron group than in those with mothers in the placebo group.

Adolescent↗
PubMed1997

Effect of micronutrient supplementation on infection in institutionalized elderly subjects: a controlled trial.

To determine the impact of a trace element and vitamin supplementation on infectious morbidity, a double-blind controlled trial was performed on 81 elderly subjects in a geriatric center during a 2-year period. Subjects were randomly assigned to one of four treatment groups, and received daily: placebo; trace elements/zinc 20 mg; selenium 100 micrograms); vitamins (vitamin C 120 mg; beta-carotene 6 mg; alpha-tocopherol 15 mg); or a combination of trace elements and vitamins at equal doses. (1) Before supplementation, low serum values in vitamin C, folate, zinc and selenium were observed in more than two thirds of the patients. (2) After 6 months of supplementation, a significant increase in vitamin and trace element serum levels was obtained in the corresponding treatment groups: a plateau was then observed for the whole study. (3) Subjects who received trace elements (zinc and selenium) alone or associated with vitamins had significantly less infectious events during the 2 years of supplementation. These results indicate that supplementation with low doses of vitamins and trace elements is able to rapidly correct corresponding deficiencies in the institutionalized elderly. Moreover, zinc and selenium reduced infectious events.

Aged↗
PubMed1997

Hydroxyurea induces the gene expression and synthesis of proinflammatory cytokines in vivo.

The anticancer agent hydroxyurea (HU) was previously found to cause dose-dependent adrenal activation in the rat. The increased secretion of corticosterone (CORT) that results appeared to protect animals against HU toxicity, which was dramatically enhanced in adrenalectomized (ADX) rats. Similarities with the endocrine and toxicological profiles of proinflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF) led us to suggest that these effects of HU might be mediated by an increased synthesis of these cytokines. The goal of this study was therefore to demonstrate that HU induces the gene expression and synthesis of proinflammatory cytokines in vivo. Intact and ADX rats were treated with HU, mRNA was extracted from spleen cells 2 and 24 hr after treatment and message levels for IL-1 alpha, IL-2, IL-4, IL-6, TNF alpha and interferon-gamma were evaluated using the reverse transcriptase-polymerase chain reaction technique. In some experiments, circulating levels of CORT and TNF were also measured. We found that transcripts of the proinflammatory cytokines, TNF, IL-6 and (though less clearly) IL-1 alpha, were expressed in the majority of intact rats treated with HU but were absent or less evident in most controls. In contrast, gene expression of IL-2, IL-4 and interferon-gamma was not influenced by drug treatment. Adrenalectomy markedly enhanced the effects of HU. Twenty-four hours after administration of the drug, the expression of TNF and IL-6 mRNAs was still higher in ADX rats compared with intact animals. Parallel measurements of plasma CORT levels revealed that gene expression of IL-1 alpha and, to a lesser extent, TNF was inversely related to levels of circulating CORT. Adrenalectomy per se caused a significant increase in plasma TNF levels compared with intact controls. Hydroxyurea elicited significant increases in circulating TNF in both ADX and intact rats. These findings lend support to our working hypothesis and provide an explanation for both the rise in glucocorticoid secretion induced by HU in intact rats and the increase in lethality observed in animals with disruptions of the hypothalamo-pituitary-adrenal axis.

Adrenalectomy↗
PubMed1997

Effects of trace element and/or vitamin supplementation on vitamin and mineral status, free radical metabolism and immunological markers in elderly long term-hospitalized subjects. Geriatric Network MIN. VIT. AOX.

A randomized double-blind trial was performed in order to assess the efficacity of differing combinations of antioxidant nutrients on biochemical parameters of vitamin and trace element status, immunological parameters and free radical metabolism in elderly long term hospitalized subjects. A total of 756 institutionalized elderly subjects were recruited in 26 nursing homes in different areas of France. Four groups were constituted, receiving daily, for 1 year, either vitamins (beta-carotene, 6 mg; vitamin C, 120 mg; and vitamin E, 15 mg), trace elements (zinc, 20 mg and selenium, 100 micrograms), trace elements associated with vitamins, or a placebo. Biochemical indicators of trace elements and vitamin status and free radical parameters were measured before and after 6 months and 1 year of supplementation. Some immunological markers were investigated initially and after 6 months of supplementation on a subsample of 134 subjects. Mean plasma levels of alpha-tocopherol, gamma-tocopherol, vitamin C, alpha-carotene, beta-carotene and copper increased significantly after 6 months of supplementation in groups receiving vitamins alone or associated with trace elements. Serum selenium concentrations were significantly increased at 6 months of supplementation, and serum zinc only after one year in the trace element groups. Serum lycopene levels were significantly decreased by trace element supplementation. A significant increase in Se-glutathione peroxidase (GPx) levels was observed in groups receiving trace elements alone or associated with vitamins. No effect was noted on superoxide dismutase (SOD) activity or TBARs production. No effect of supplementation was found for in vitro lymphocyte proliferative responses or most lymphocyte subsets, except for a significantly lower percentage of CD2 subsets observed in groups receiving mineral supplementation either alone or associated with vitamins. A significant difference in CD19 subsets was found in groups receiving trace elements. Mean IL-1 production was significantly higher after 6 months of supplementation in the vitamin groups.

Aged↗
PubMed1997

Dietary magnesium intake in a French adult population.

Magnesium intake was assessed using six 24-h dietary records during a 1-year period in 5,448 subjects (3,111 women 35-60 yrs old and 2,337 men 45-60 yrs old) in the SU.VI.MAX cohort, selected at a national level in France. The overall mean dietary intake was estimated at 369 +/- 106 mg/day in men and 280 +/- 84 mg/day in women. 77 per cent of women and 72 per cent of men had dietary magnesium intakes lower than recommended dietary allowances; 23 per cent of women and 18 per cent of men consumed less than 2/3 of these RDA. A strong positive correlation existed between energy and magnesium intake (r = 0.79; p < 10(-4)). Slight variations were observed according to socio-professional and educational levels and place of residence. Cereal products represented the main contribution in both men (21 per cent) and women (19.8 per cent). In men, the second source was represented by alcoholic beverages (11.7 per cent), which were a lower source of magnesium in women (5.5 per cent). Dairy products, vegetables, meat and poultry were the other main sources of dietary magnesium intake.

Adult↗
PubMed1996

Evidence for the neuronal origin of immunoreactive interleukin-1 beta released by rat hypothalamic explants.

In this study, we have investigated the release of immunoreactive interleukin-1 beta (irIL-1 beta) from the rat hypothalamus in vitro. It was found that (1) tissue explants release sizable amounts of irIL-1 beta (ranging from 0.43 to 0.52 pg/mg of wet tissue) in 20 min incubations; (2) basal release in significantly increased by depolarization induced with 56 mM KCl; (3) K(+)-induced irIL-1 beta release is inhibited by the specific blocker of N-type calcium channels, omega-conotoxin, and by verapamil, but not by nifedipine; (4) K(+)-induced release is also inhibited by the Na+ channel blockers tetrodotoxin and lidocaine; (5) irIL-1 beta release is significantly increased by noradrenalin; such increase is antagonized by verapamil and the beta-blocker propranolol, but not by the alpha-blocker phentolamine. The present evidence suggests that irIL-1 beta released by rat hypothalamic explants following KCl depolarization is neuronal in origin.

Animals↗
PubMed1996

Interleukin-1 beta specifically stimulates nitric oxide production in the hypothalamus.

In previous experiments we have shown the role of nitric oxide (NO) in basal and interleukin-1 beta (IL-1 beta)-induced CRH and ACTH release in vitro. Now, we have studied the possible production of NO from hypothalamic cell cultures, particularly after IL-1 beta stimulation or L-NOArg inhibition, by high performance liquid chromatographic (HPLC) assay of L-citrulline production, adding further evidence for a role of NO in IL-1 beta activity in the hypothalamus.

Animals↗
PubMed1996

The effects of inhibitors of cyclo-oxygenase, lipoxygenase and nitric oxide synthase pathways on the toxicity of hydroxyurea in adrenalectomized rats.

Our previous observations on the toxic effects of hydroxyurea (HU) in adrenalectomized (ADX) rats prompted us to suggest that these effects might be mediated by an increased synthesis of proinflammatory cytokines, which display similar toxicological profiles (e.g. increased lethality in adrenal-ablated animals). The present study was aimed at investigating whether some of the mediators of the biological effects of pro-inflammatory cytokines (i.e. prostaglandins, leukotrienes, and nitric oxide) are involved in the severe HU toxicity seen in ADX rats. The latter were treated over a 5-day period with HU alone or HU plus specific inhibitors of prostaglandin, leukotriene and nitric oxide synthetic pathways. Mortality was recorded throughout the experiments. Results showed that, while corticosterone and dexamethasone afford significant protection against HU toxicity, the latter is not reduced and may even be aggravated by treatments with specific inhibitors of cyclo-oxygenase, lipoxygenase or nitric oxide synthase.

Adrenalectomy↗
PubMed1996

Diet quality and dietary diversity in France: implications for the French paradox.

OBJECTIVES: Assessing the quality of the total diet is a relatively new focus of studies in nutritional epidemiology. New indexes of healthful eating patterns have been largely limited to US populations. This study used evaluative criteria developed in the United States to assess diet quality and dietary diversity of French adults. METHODS: Habitual dietary intakes of a representative sample of 837 adults (361 men and 476 women) in the Val-de-Marne Dèpartement were evaluated. Evaluative measures of diet quality included a modified diet quality index (DQI), a dietary diversity (DD) score, and a dietary variety score (DVS). The 5-point DQI assessed compliance with the key guidelines of the US Department of Agriculture (USDA) for healthy people. The DD score counted the number of major food groups consumed whereas the DVS counted the total number of foods consumed on a regular basis. RESULTS: Few French adults consumed diets consistent with the USDA dietary recommendations. Only 14% of respondents derived less than 30% of energy from fat and only 4% derived less than 10% of energy from saturated fat. As a result, 63% of the sample had DQI scores of either 0 or I. In contrast, close to 90% of respondents scored a maximum of 5 in DD. Persons whose diets met US dietary recommendations also had the lowest DVSs. CONCLUSIONS: Methodologic factors and cultural biases may account for some of the observed differences between French and US data. Nevertheless, studies of diet quality and diversity are a promising new approach to the study of the total diet and associated health outcomes and may provide new insight into the French paradox.

Adolescent↗
PubMed1996

Nitric oxide synthase activity and non-adrenergic non-cholinergic relaxation in the rat gastric fundus.

1. In the presence of atropine (1 microM) and guanethidine (5 microM), electrical field stimulation (EFS, 120 mA, 1 ms, 0.5-16.0 Hz, trains of 2 min) induced frequency-dependent relaxations of 5-hydroxytryptamine (3 microM)-precontracted longitudinal muscle strips from the rat gastric fundus. 2. L-Citrulline concentrations were measured in the incubation medium of precontracted strips before and after EFS to investigate nitric-oxide (NO) synthase activity and its possible relation to non-adrenergic non-cholinergic (NANC) relaxation. 3. Basal NO synthase activity was reflected by the finding of prestimulation levels of L-citrulline of approximately 30 nM. These levels were unaffected by tetrodotoxin (3 microM) and NG-nitro-D-arginine methyl ester (D-NAME, 100 microM), slightly reduced by a calcium-free medium and halved by NG-nitro-L-arginine methyl ester (L-NAME, 100 microM). 4. EFS evoked significant, frequency-dependent increases in bath levels of L-citrulline at all frequencies tested. The increases evoked by 16-Hz EFS were abolished by tetrodotoxin (3 microM), a calcium-free medium and L-NAME (100 microM) but not by D-NAME (100 microM). 5. L-NAME (0.1 microM-1.0 mM) produced significant reduction of 4-Hz EFS-induced L-citrulline production (100% inhibition at 10 microM), but had less marked effects on basal production (approximately 50% reduction at 100 microM) and 4-Hz EFS-induced NANC relaxation (approximately 50% reduction at 1 mM). 6. L-Arginine (1 mM), but not D-arginine (1 mM), increased basal L-citrulline levels and reversed the inhibitory effect of L-NAME (10 microM). 7. These findings represent clear biochemical evidence of both basal and EFS-stimulated NO synthase activity in the rat gastric fundus.

Animals↗
PubMed1996

Interleukin-1 beta release from rat gastric fundus.

Interleukin-1 (IL-1) is known to regulate gastric functions via a central action at the hypothalamic level, and it has also been shown that this cytokine can directly modulate rat gastric motility. This study was conducted to determine whether IL-1 beta is produced and released by rat gastric fundi in vitro. IL-1 beta immunoreactivity was released in measurable amounts from explanted rat gastric tissue. This release was not affected by electrical stimulation of the gastric strips or by agents that induce IL-1 biosynthesis. It could be inhibited only by the glucocorticoid dexamethasone. Ex vivo experiments confirmed the inhibitory role of glucocorticoids and showed that IL-1 beta release can be inhibited by agents that reduce gastric acid secretion, suggesting that the latter might stimulate IL-1 beta synthesis and release. In light of the well-established gastroprotection exerted by IL-1, H(+)-induced IL-1 beta release might serve as a protection against mucosal injuries caused by acid secretion, and the inhibition of this release by glucocorticoids might be involved in the pathogenesis of gastric damage associated with severe stress or steroid therapy.

Adrenalectomy↗
PubMed1996

Micronutrient status in elderly people. Geriatrie/Min. Vit. Aux Network.

A biochemical assessment of the vitamin and trace element status of 756 institutionalized elderly men and women, 66-103 years old (average 83.5 +/- 7.6 y), was conducted in 26 nursing homes in different areas of France. Serum concentrations of beta- and alpha-carotene, beta-cryptoxanthin, lycopene, retinol, alpha- and gamma-tocopherol, vitamin C, zinc and selenium were measured. A difference in biochemical markers according to sex was observed for vitamins E and C: elderly women had higher levels of alpha-tocopherol and vitamin C than elderly men. When expressed as a ratio of cholesterol, the difference between sexes for alpha-tocopherol disappeared. Simple regression analysis showed that most vitamins and trace elements were significantly negatively correlated with age. A high prevalence of low concentrations of vitamin C, zinc and selenium was revealed.

Aged↗