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Biomedical subjects

M Zaccaria

Publications and source records attributed to M Zaccaria.

At least 19 recordsLinked to original sources
PubMed2005

Completion of screening for latent tuberculosis infection among immigrants.

The objective of our study was to evaluate the sociodemographic factors associated with completion of screening for latent tuberculosis infection (LTBI) among undocumented immigrants in Brescia, Italy. Screening for LTBI was offered to 649 immigrants; 213 (33%) immigrants completed the first step of screening; only 44% (55/124) of individuals with a positive tuberculin skin test result started treatment for LTBI. The univariate analysis showed that being unmarried, of Senegalese nationality and being interviewed by a health-care worker with the same native language as the immigrant were significantly associated with completion of screening for LTBI. In the multiple logistic regression, being interviewed in the native language of the health-care worker (OR 2.5, 95% CI 1.3-4.8, P = 0.004) and being of Senegalese origin (OR 2.3, 95% CI 1.4-3.6, P = 0.0005) were independently associated with adherence to LTBI screening. Our results suggest that knowledge of the sociodemographic characteristics of immigrants, and the participation of health-care workers of the same cultural origin as the immigrant during the visits, can be an important tool to improve completion of screening for LTBI.

Adult↗
PubMed2005

Zinc intake and status in middle-aged and older European subjects: the ZENITH study.

OBJECTIVE: Inadequate intakes of micronutrients in elderly negatively affect the nutritional status. Zinc is an essential micronutrient in the elderly, especially in relation to its impact on immune function, bone mass, cognitive function and oxidative stress. However, data are lacking on zinc intake and status during normal ageing. In this study, we evaluate the intake and status of zinc in late middle-aged and older free-living subjects. DESIGN: Dietary zinc intake and zinc status in 188 middle-aged subjects from Clermont-Ferrand (Fr) and Coleraine (UK), and in 199 older subjects from Grenoble (Fr) and Roma (It) were assessed at the entry in the ZENITH study. RESULTS: In relation to the zinc RDA for people older than 55 y, zinc intakes in most of the middle-aged and older subjects (more than 96%) in the present study were adequate. Older people had significantly lower (P < 0.01) energy intakes as compared to middle-aged. Zinc intake expressed per MJ was also significantly (P < 0.01) higher in older people compared to middle-aged. Erythrocyte and urinary zinc concentrations were significantly (P < 0.001) higher in middle-aged subjects compared to older ones. The prevalence of biological Zn deficiency in free-living ageing European people was low (<5%). CONCLUSION: The results of the present study showed a relatively low prevalence of zinc deficiencies in healthy free-living late middle-age and older subjects. These results should be useful for health professionals to have reference data on zinc intake and status for a healthy ageing.

Age Factors↗
PubMed2003

Effect of licorice on the reduction of body fat mass in healthy subjects.

The history of licorice, as a medicinal plant, is very old and has been used in many societies throughout the millennia. The active principle, glycyrrhetinic acid, is responsible for sodium retention and hypertension, which is the most common side-effect. We show an effect of licorice in reducing body fat mass. We studied 15 normal-weight subjects (7 males, age 22-26 yr, and 8 females, age 21-26 yr), who consumed for 2 months 3.5 g a day of a commercial preparation of licorice. Body fat mass (BFM, expressed as percentage of total body weight, by skinfold thickness and by bioelectrical impedance analysis, BIA) and extracellular water (ECW, percentage of total body water, by BIA) were measured. Body mass index (BMI) did not change. ECW increased (males: 41.8+/-2.0 before vs 47.0+/-2.3 after, p<0.001; females: 48.2+/-1.4 before vs 49.4+/-2.1 after, p<0.05). BFM was reduced by licorice: (male: before 12.0+/-2.1 vs after 10.8+/-2.9%, p<0.02; female: before 24.9+/-5.1 vs after 22.1+/-5.4, p<0.02); plasma renin activity (PRA) and aldosterone were suppressed. Licorice was able to reduce body fat mass and to suppress aldosterone, without any change in BMI. Since the subjects were consuming the same amount of calories during the study, we suggest that licorice can reduce fat by inhibiting 11beta-hydroxysteroid dehydrogenase Type 1 at the level of fat cells.

Adipose Tissue↗
PubMed2000

Effects of prolonged high-altitude exposure on peripheral adrenergic receptors in young healthy volunteers.

The regulation of adrenergic receptors during hypoxia is complex, and the results of published reports have not been consistent. In the present study blood cell adrenoceptor characteristics at sea level (SL) before and after prolonged exposure to high altitude (HA) were measured in seven trained young male lowlanders. Sympathoadrenal activity and clinical haemodynamic parameters were also evaluated before departure (SLB), after 1 week (HA1) and 4 weeks (HA4) at HA and 1 week after return to sea level (SLA). As compared to pre-departure sea level values, urinary norepinephrine excretion increased significantly during altitude exposure [SLB: 10.26 (3.04) microg x 3 h(-1); HA1: 23.2 (4.19) microg x 3 h(-1); HA4: 20.3 (8.68) microg x 3 h(-1)] and fell to pre-ascent values 1 week after return to sea level [SLA: 9 (2.91) microg x 3 h(-1)]. In contrast, mean urinary epinephrine levels did not increase over time at HA. Both systolic and diastolic blood pressures, as well as heart rate, were increased during HA exposure. The circadian blood pressure and heart rate rhythms were preserved during all phases of altitude exposure. Mean maximal binding (Bmax) of the alpha2-adrenoceptor antagonist [3H]rauwolscine to platelet membranes was significantly reduced (P < 0.001) after exposure to chronic hypoxia [SLB: 172.6 (48.5) fmol x mg(-1) protein versus SLA: 136.8 (56.1) fmol x mg(-1) protein] without change in the dissociation constant (K(D)). Neither the lymphomonocyte beta2-adrenoceptor Bmax [SLB: 38.5 (13.6) fmol x mg(-1) protein, versus SLA: 32.4 (12.1) fmol mg(-1) protein] nor the K(D) for [3H]dihydroalprenolol was affected by chronic hypoxia. Cyclic AMP (adenosine 3',5'-cyclic monophoshate) generation in lymphomonocytes by maximal isoproterenol stimulation was not modified after prolonged HA exposure. In conclusion, the down-regulation of alpha2-adrenoceptors appears to be an important component of the adrenergic system response to HA exposure.

Adenylyl Cyclases↗
PubMed1999

Blunted growth hormone response to maximal exercise in middle-aged versus young subjects and no effect of endurance training.

The purpose of this study was to evaluate the GH response to exercise and the effects of endurance training on this response in early middle-aged men. Seven healthy middle-aged [M; 42.0+/-2.4 (+/-SD) yr old] and five young (Y; 21.2+/-1.1 yr old) competition cyclists were investigated before and after 4 months of intensive endurance training. Subjects performed an exhaustive incremental exercise test (50 watts for 3 min) with gas exchange measurement, and blood samples for lactate, glucose, and GH determinations were drawn before exercise, at the end of the exercise, and in the recovery phase (1, 3, 5, 10, 15, 20, and 30 min). Basal insulin-like growth factor I was also determined. At exhaustion no differences were found in relative maximal heart rate or blood lactate and glucose peaks. On the contrary, the two groups had markedly different GH responses; in fact, the peak GH response to exhaustive exercise was much lower in M than in Y (8.1+/-1.3 vs. 57.1+/-15.5 microg/L; P<0.01). The training, similar in subjects of the same group, increased progressively from 182 to 300 km/week (+64.8%) in M and from 350 to 600 km/week (+71.4%) in Y. After the training, the percent increase in maximal oxygen consumption was similar in the two groups (M, +15.2%; Y, +17.5%), confirming that the efficiency of the training performed was comparable. In neither group did training have any effect on the GH peak response to exercise, confirming the blunted GH response in M compared to Y (6.7+/-1.0 vs. 61.0+/-12.9 microg/L; P<0.01). Similarly, insulin-like growth factor I concentrations were not significantly affected by training. In conclusion, active middle-aged subjects, compared with the young, showed a blunted GH response to a physiological stimulus such as exercise, indicating that the age-related decline in GH secretion appears in early middle age. This response was not modified by training in either early middle-aged or young subjects.

Adult↗
PubMed1998

Sodium regulating hormones at high altitude: basal and post-exercise levels.

High altitude (HA)-induced diuresis is associated with marked changes in sodium and water regulating hormones, particularly the renin-angiotensin-aldosterone system (RAAS) and atrial natriuretic hormone (ANH). These hormones are also strongly stimulated by physical exercise, which is a major component of daily activity at HA. In spite of the numerous studies in literature, a clear relationship between hormonal changes, HA diuresis, and physical exercise has not yet been established. We therefore evaluated the response of sodium regulating hormones to exhaustive exercise in a group of seven males exposed to prolonged HA hypoxia. The study was divided into four phases: sea level (SL1), after 7 (P1) and after 21 (P2) days at 5050 m (Italian National Research Council Pyramid Laboratory, Nepal), and back at sea level (SL2). At each phase plasma hematocrit (Ht), total body water (TBW), 24-hr sodium excretion (uNa), and urinary volume (uV) were evaluated together with PRA, plasma aldosterone, and ANH, in samples drawn basally from patients in upright position, and at the end of graded step-wise (30 W/2 min) maximal exercise. Levels of uNa and uV were raised at P1 and then declined at P2, with a parallel decrease in TBW and an increase in Ht. Basal PRA and aldosterone levels were suppressed both at P1 and P2 (from 1.9 +/- 0.4 to 0.08 +/- 0.03 and 0.5 +/- 0.1 ng/mL/3 h, and from 7.9 +/- 1.8 to 3.9 +/- 0.4 and 4.5 +/- 0.4 ng/dL, respectively; P < .05). Exhaustive exercise at HA did not induce any significant response in PRA and aldosterone, unlike SL1. Otherwise at P1 ANH levels remained unchanged both basally and during exercise, while at P2 they decreased significantly vs. SL1, both basally and after exercise (from 13.3 +/- 5.7 to 3.5 +/- 1.2 and from 40.2 +/- 10.2 to 17.5 +/- 8.3, respectively; P < .05). Our data show that PRA and aldosterone levels were constantly suppressed at HA and were unresponsive to exercise, whereas the ANH response was significantly stimulated during acute HA exposure, but not during chronic exposure. This suggests that hypoxia-induced chemoreceptor stimulation may cause the natriuretic phenomenon through direct suppression of the RAAS.

Adrenocorticotropic Hormone↗
PubMed1997

Effects of high-altitude chronic hypoxia on platelet alpha 2-receptors in man.

During chronic high-altitude (HA) exposure, basal and exercise-induced noradrenaline (NA) increases do not parallel blood pressure (BP) changes observed; unlike beta-adrenergic receptors, to our knowledge no data are available on alpha-receptors. We studied platelet alpha 2- and leucocyte beta-receptors and basal catecholamine levels in 11 trained climbers before and after they had spent a 15-day period at a height of over 4400 m. In six of the climbers we also evaluated catecholamines after maximal bicycle ergometer exercise. After chronic high-altitude exposure, a significant decrease was found in platelet alpha 2-receptor density and affinity [Bmax from 92.6 +/- 6.7 to 54.6 +/- 4.2 fmol mg-1 protein (P < 0.001) and KD from 1.271 +/- 0.034 to 1.724 +/- 0.077 nmol L-1 (P < 0.05)], although no changes to beta-receptors were observed. No changes were found in basal pre- and post-expedition NA and adrenaline (A), and there was only a slight decrease in post-expedition NA after maximal exercise. Our results suggest that prolonged exposure to hypoxia induces a down-regulation of alpha 2-receptors, which may be a contributory factor in the regulation of the physiological vascular response to acclimatization.

Adult↗
PubMed1996

A new method for monitoring hydration at high altitude by bioimpedance analysis.

Our study evaluated the performance of a graphical method for monitoring the fluid variation at high altitude in seven adult Caucasian male subjects (average age 25 yr, average height 177 cm). The graphical approach is called the Resistance-Reactance (RXc) graph method and is based on standard bioimpedance analysis (tetrapolar, 50 kHz frequency). Measurements were taken at sea level before the expedition, at 5050 m after 1 wk and 3 wk, and again at sea level after descent. Plasma and urine electrolytes, osmolalities, and the free-water clearance were determined by standard methods. All climbers had baseline impedance vectors within the reference 95% tolerance ellipse for the Italian male population. The high altitude dehydration caused a significant lengthening of vectors, which after descent underwent a significant shortening and returned close to the baseline values. Average urine volume increased by 1.4 l.d-1 in the first week and average body weight decreased by 4.4 kg after 3 wk. The RXc graph method could be useful in the planning of the individual climber's appropriate dehydration and fluid intake at altitude since a feedback control of the hydration is allowed without any assumption of body composition.

Acclimatization↗
PubMed1994

Cardiovascular neural regulation during and after prolonged high altitude exposure.

Eight young healthy male subjects, members of a Himalayan expedition, underwent 24 h Holter monitoring before departure, after 1 and 4 weeks at high altitude (5000 m) and after return to sea level. At high altitude, the circadian reciprocal changes in low and high frequency (LF, HF) were absent, with no significant reduction in the LF to HF ratio over the 24 h; moreover, the proportion of adjacent R-R intervals that differed by more than 50 ms (pNN50) decreased significantly and remained lower after return to sea level. Urine catecholamines increased at high altitude, but only norepinephrine, after 1 week of exposure, rose significantly. Upon return to sea level the density, but not the affinity, of [alpha]2-adrenergic receptors on platelets decreased significantly compared to pre-expedition values. At high altitude increased sympathetic activity was indicated by elevation of urine norepinephrine and by the loss of circadian rhythm in spectral components. The simultaneous reduction of HF and pNN50 demonstrated decreased vagal tone. The persistence of increased sympathetic activity could explain the downregulation of adrenergic receptors after prolonged high altitude exposure.

Adult↗
PubMed1985

Effects of pirenzepine on plasma insulin, glucagon and pancreatic polypeptide levels in normal man.

The secretion of various pancreatic hormones (insulin, glucagon and pancreatic polypeptide) is affected to a different extent by the cholinergic system. In 7 healthy subjects the effects of treatment for 1 week with pirenzepine, an anticholinergic drug selective for muscarinic receptors, on basal secretion of these hormones and on that induced by i.v. glucose (IVGTT) and arginine were evaluated. The drug did not reduce basal levels of insulin and glucagon whereas it caused an appreciable reduction in basal pancreatic polypeptide (PP). The responses of insulin and blood glucose to IVGTT and to arginine were not changed by treatment, nor was that of plasma glucagon to arginine. The infusion of arginine did induce an increase in PP level, which reached a statistically significant maximum at 90 min. This response was not particularly different after administration of pirenzepine. Thus, the results confirm the finding that arginine stimulates PP secretion in vivo and that pirenzepine reduces the basal level of the hormone, whereas it did not appear to affect the response to arginine. The findings exclude any direct action of the drug on insulin or glucagon secretion or on glucose metabolism in general.

Adult↗
PubMed1985

Lack of effect of im diazepam administration on hGH and hPRL secretion in normal and acromegalic subjects.

The usefulness of diazepam as a provocative stimulus for hGH secretion has been suggested as a simple, reliable test in clinical hGH assessment of pituitary disorders. We have investigated the effects of diazepam (10 mg im) on plasma hGH and hPRL in 5 normal and 7 acromegalic subjects. No significant variations in hGH and hPRL levels have been observed in any of the studied subjects. These findings indicate that the drug is ineffective on hGH and hPRL release and that it cannot be considered a valid provocative test either in normal or acromegalic subjects.

Acromegaly↗
PubMed1980

Effects of sodium DL-lactate on insulin secretion in anesthetized dogs.

The effect of sodium DL-lactate administration on insulin release in anesthetized dogs has been studied. Eleven mongrel dogs were infused with sodium DL-lactate for 20 min at the rate of 20 mg/kg . min. Lactate infusion produced simultaneous increases in blood glucose and plasma insulin levels in the pancreaticoduodenal vein. To determine whether lactate stimulated insulin secretion directly, sodium DL-lactate was rapidly injected into the pancreatic artery of six dogs; this pulse induced a significant increase in insulin release from pancreatic B-cells, even in the absence of a measurable change in blood glucose. Diazoxide, when infused in six dogs, blocked lactate-induced insulin secretion. These findings indicate that lactate, as do other circulating energy fuels, may play a role in the physiologic control of insulin secretion.

Animals↗
PubMed1978

The effect of propranolol on hypoglycaemia. Observations in five insulinoma patients.

Five hypoglycaemic hyperinsulinaemic patients (three with proven benign insulinoma, one with proven metastasizing insulinoma, one with probable insulinoma not found at surgery) were treated with propranolol for a variable time ranging from two weeks to one year. Three patients showed favourable clinical results and a significant increase of the mean basal blood glucose level was found while two patients showed no improvement of the frequency of neuroglycopenic episodes and no significant increase of their mean blood glucose level. No patient showed a significant decrease in mean basal IRI concentration. A decrease of insulinaemic responses was observed during oral and intravenous glucose tolerance tests, a prolonged fast, and tolbutamide and glucagon tests performed in some patients. The results suggest that propranolol may induce in certain patients an improvement of basal clinical status through not understood effects (probably hepatic), which leave the peripheral concentrations of insulin unchanged, whereas inhibition of insulin secretion may represent the main way by which the improvement of metabolic situation during physiological or pharmacological stimulation may have been achieved.

Adenoma, Islet Cell↗