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Biomedical subjects

S Andreoni

Publications and source records attributed to S Andreoni.

At least 19 recordsLinked to original sources
PubMed2000

Oxygen cost for cycling as related to leg mass in males and females, aged 20 to 80.

In order to evaluate the determinants of the metabolic cost for cycle ergometry, we analyzed the relationship between VO2 and leg mass (LM) and total body mass (TBM) in 71 randomly-selected sedentary subjects (34 men), aged 20 to 80. Participants performed constant work rate (WR) tests at 0, 25, and 50 W (at 60 rpm) for 6 minutes in a randomized sequence: gross VO2, gross efficiency, and work efficiency were related to TBM and LM as assessed by dual energy x-ray absorptiometry. We found that gross VO2 and gross efficiency were more strongly related to LM than TBM but work efficiency values were independent of both (P>0.05). Significantly higher values of VO2TBM were found in subjects with large LM/TBM ratios and vice-versa; VO2/LM, however, did not change with anthropometric characteristics. Gross VO2 (mL/min) was predicted by a LM-based equation (10.6 [WR, W] + 16.8 [LM, kg] +75) with a mean error below 5%: this equation predicted the cost more accurately than previous TBM-based formulations (P<0.01). We conclude that leg mass actually provides the preferred frame of reference for predicting the oxygen cost for cycle ergometry at 60 rpm in sedentary subjects, independent of age or gender.

Absorptiometry, Photon↗
PubMed1999

Maximal aerobic power and leg muscle mass and strength related to age in non-athlethic males and females.

To investigate the relationships between the age-associated decline in peak oxygen uptake (peak VO2), leg muscle mass (LMM) and leg strength (LS) under the modulating effect of gender and level of physical activity (LPA, as assessed by questionnaire), we evaluated 71 sedentary subjects [males(M):females(F), 34:37], aged 20-80 years. Peak VO2 at maximum cycle ergometry was related to LMM (dual energy X-ray absorptiometry) and LS (isokinetic dynamometry) using both standard (y x x(-1)) and power function ratios (allometry). Absolute values of all variables were higher in males and declined with age (P < 0.01). Differences between the genders disappeared after peak VO2 x LS(-1.46(M)or -1.62(F)) adjustment but remained significant between peak VO2 LMM-(-0.51 (M)or -0.45(F)) and LS LMM- (-091(M) or -1.10(F)) corrected values. Allometric correction of peak VO2 and LS by LMM slowed their age-related declines; the flattening effect however, was more evident in the females. Interestingly, while no age-related decrement in peak VO2 LS(-1) was found, power function ratio values also declined with age, and at a slower rate in females. These findings are consistent with those obtained following a multiple regression analysis using LPA as an independent covariate (P < 0.01). We conclude that using adequate scaling methods and controlling by LPA: (1) no gender differences are observed in peak VO2 adjusted for LS, (2) loss of LS and LMM are important determinants of the age-associated reduction in physical fitness in both genders but (3) age per se has an LS- and LMM-independent influence on the functional decline, although this intrinsic effect of senescence is less pronounced in females.

Adult↗
PubMed1999

The effect of unmodified or prestorage white cell-reduced allogeneic red cell transfusions on the immune responsiveness in orthopedic surgery patients.

BACKGROUND: The immunomodulatory effects of allogeneic blood transfusions have been attributed to the white cells (WBCs) present in the cellular blood components transfused to patients. STUDY DESIGN AND METHODS: The effect of the transfusion of allogeneic red cells (RBCs) or allogeneic prestorage WBC-reduced RBCs (WBC-reduced RBCs) on host immune responsiveness was evaluated by measuring the lymphocyte subsets and the in-vitro cytokine production in response to phytohemagglutinin stimulation of WBCs of orthopedic surgery patients. Forty-seven patients undergoing hip replacement surgery were randomly assigned to receive allogeneic RBCs (n = 17) or WBC-reduced RBCs (n = 14; 99.95% WBC removal). Sixteen patients were not transfused. Patient blood samples taken before surgery and on Days 1 and 4 after surgery were tested for complete blood count, lymphocyte subset analysis, and measurement of cytokine levels. RESULTS: After surgery, the lymphocyte count was significantly decreased in patients transfused with > or = 3 units of allogeneic RBCs (2.0 +/- 0.5 vs. 1.3 +/- 0.3 x 10(9)/L; p = 0.017), but not in patients transfused with > or = 3 units of WBC-reduced RBCs (2.0 +/- 0.9 vs. 1.7 +/- 0.8 x 10(9)/L). Compared with preoperative levels, on Day 4 after surgery, patients transfused with > or = 3 units of allogeneic RBCs also had a decrease in the number of natural killer cells (0.07 +/- 0.05 vs. 0.04 +/- 0.03 x 10(9)/L; p = 0.018). Postoperatively, interleukin-2 was decreased in one patient who received WBC-reduced RBCs compared with that in four patients transfused with allogeneic RBCs (p = 0.32), and eight untransfused patients (p = 0.01). On Day 4, about 70 percent of patients transfused with allogeneic RBCs showed a 20-percent decrease in the interferon gamma level. CONCLUSION: Taken together, these data support the hypothesis that transfusion of > or = 3 units of allogeneic RBCs is associated with early postoperative lymphopenia in otherwise healthy individuals undergoing surgery. These findings were not observed in those individuals transfused with RBCs that had undergone prestorage WBC reduction.

Adult↗
PubMed1999

Prediction of metabolic and cardiopulmonary responses to maximum cycle ergometry: a randomised study.

All of the most widely-cited studies for the prediction of maximum exercise responses have utilized either volunteers or referred subjects. Therefore, selection bias, with overestimation of the reference values, is a likely consequence. In order to establish a set of predictive equations for the gas exchange, ventilatory and cardiovascular responses to maximum ramp-incremental cycle ergometry, this study prospectively evaluated 120 sedentary individuals (60 males, 60 females, aged 20-80), randomly-selected from >8,000 subjects. Regular physical activity pattern by questionnaire, body composition by anthropometry and dual energy X-ray absorptiometry (n = 75) and knee strength by isokinetic dynamometry were also assessed. Previously reported equations typically overestimated the subjects' peak oxygen uptake (p<0.05). Prediction linear equations for the main variables of clinical interest were established by backward stepwise regression analysis including: sex, age, knee extensor peak torque, bone-free lean leg mass, total and lean body mass, height, and physical activity scores. Reference intervals (95% confidence limits) were calculated: some of these values differed markedly from those formerly recommended. The results therefore might provide a more appropriate frame of reference for interpretation of the responses to symptom-limited ramp incremental cycle ergometry in sedentary subjects; i.e. those usually referred for clinical cardiopulmonary exercise tests.

Adult↗
PubMed1999

Reference values for lung function tests. I. Static volumes.

Static lung volume (LV) measurements have a number of clinical and research applications; however, no previous studies have provided reference values for such tests using a healthy sample of the adult Brazilian population. With this as our main purpose, we prospectively evaluated 100 non-smoking subjects (50 males and 50 females), 20 to 80 years old, randomly selected from more than 8,000 individuals. Gender-specific linear prediction equations were developed by multiple regression analysis with total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), RV/TLC ratio and inspiratory capacity (IC) as dependent variables, and with age, height, weight, lean body mass and indexes of physical fitness as independent ones. Simpler demographic and anthropometric variables were as useful as more complex measurements in predicting LV values, independent of gender and age (R2 values ranging from 0.49 to 0.78, P < 0.001). Interestingly, prediction equations from North American and European studies overestimated the LV at low volumes and underestimated them at high volumes (P < 0.05). Our results, therefore, provide a more appropriate frame of reference to evaluate the normalcy of static lung volume values in Brazilian males and females aged 20 to 80 years.

Adult↗
PubMed1999

Reference values for lung function tests. II. Maximal respiratory pressures and voluntary ventilation.

The strength of the respiratory muscles can be evaluated from static measurements (maximal inspiratory and expiratory pressures, MIP and MEP) or inferred from dynamic maneuvers (maximal voluntary ventilation, MVV). Although these data could be suitable for a number of clinical and research applications, no previous studies have provided reference values for such tests using a healthy, randomly selected sample of the adult Brazilian population. With this main purpose, we prospectively evaluated 100 non-smoking subjects (50 males and 50 females), 20 to 80 years old, selected from more than 8,000 individuals. Gender-specific linear prediction equations for MIP, MEP and MVV were developed by multiple regression analysis: age and, secondarily, anthropometric measurements explained up to 56% of the variability of the dependent variables. The most cited previous studies using either Caucasian or non-Caucasian samples systematically underestimated the observed values of MIP (P < 0.05). Interestingly, the self-reported level of regular physical activity and maximum aerobic power correlates strongly with both respiratory and peripheral muscular strength (knee extensor peak torque) (P < 0.01). Our results, therefore, provide a new frame of reference to evaluate the normalcy of some useful indexes of respiratory muscle strength in Brazilian males and females aged 20 to 80.

Adult↗
PubMed1999

Reference values for lung function tests. III. Carbon monoxide diffusing capacity (transfer factor).

Carbon monoxide diffusing capacity (DLCO) or transfer factor (TLCO) is a particularly useful test of the appropriateness of gas exchange across the lung alveolocapillary membrane. With the purpose of establishing predictive equations for DLCO using a non-smoking sample of the adult Brazilian population, we prospectively evaluated 100 subjects (50 males and 50 females aged 20 to 80 years), randomly selected from more than 8,000 individuals. Gender-specific linear prediction equations were developed by multiple regression analysis with single breath (SB) absolute and volume-corrected (VA) DLCO values as dependent variables. In the prediction equations, age (years) and height (cm) had opposite effects on DLCOSB (ml min-1 mmHg-1), independent of gender (-0.13 (age) + 0.32 (height) - 13.07 in males and -0.075 (age) + 0.18 (height) + 0.20 in females). On the other hand, height had a positive effect on DLCOSB but a negative one on DLCOSB/ VA (P < 0.01). We found that the predictive values from the most cited studies using predominantly Caucasian samples were significantly different from the actually measured values (P < 0.05). Furthermore, oxygen uptake at maximal exercise (VO2max) correlated highly to DLCOSB (R = 0.71, P < 0.001); this variable, however, did not maintain an independent role to explain the VO2max variability in the multiple regression analysis (P > 0.05). Our results therefore provide an original frame of reference for either DLCOSB or DLCOSB/VA in Brazilian males and females aged 20 to 80 years, obtained from the standardized single-breath technique.

Adult↗
PubMed1998

Vitamin D receptor gene polymorphism: correlation with bone mineral density in a Brazilian population with insulin-dependent diabetes mellitus.

Patients with insulin-dependent diabetes mellitus (IDDM) are at higher risk of developing osteoporosis. Among the genetic factors related to the development of osteoporosis, a possible association between vitamin D receptor (VDR) gene polymorphism and bone mineral density (BMD) has been described in some populations. We characterized the VDR gene polymorphism in a healthy adult Brazilian population and in a group of patients with IDDM and correlated these findings with densitometric values in both groups. The Brazilian population is characterized by an important racial heterogeneity and therefore is considered an ethnically heterogeneous population. We recruited 94 healthy adult Brazilian volunteers (63 women and 31 men), mean (+/- SD) age 32.4 +/- 6.5 years (range 18-49 years), and 78 patients with IDDM (33 women and 45 men) diagnosed before 18 years of age, mean (+/- SD) age 23.3 +/- 5.5 years (range 18-39 years). VDR genotype was assessed by polymerase chain reaction amplification followed by BsmI digestion on DNA isolated from peripheral blood leukocytes. Statistical analysis included Bonferroni t-test to compare densitometric values within different genotypes in both groups and multiple regression analysis of bone density adjusted for potential confounding factors. The IDDM group had a lower BMD compared with the control group. The VDR genotype distribution in the control group was 43 Bb (45.7%), 39 bb (41.5%) and 12 BB (12.8%). This distribution did not differ from that observed in the IDDM group: 39 Bb (50%), 26 bb (33.3%) and 13 BB (16.7%). In the IDDM group, patients with the Bb genotype had a higher body weight when compared with the BB genotype (p = 0.02). However, when diabetic patients were controlled for age, sex and body mass index, BB genotype was associated with a lower mean BMD at lumbar spine and femoral neck than in Bb and bb patients. BB patients had a shorter duration of IDDM than bb and Bb patients. These findings suggest a small influence of VDR gene polymorphism on BMD of a racially heterogeneous population with IDDM.

Adolescent↗
PubMed1998

Lp(a) in hypertensive patients.

Lipoprotein(a) (Lp(a)) is considered an important risk factor for coronary disease, cerebrovascular pathology and re-stenosis of coronary bypass. Few studies have been conducted on this lipoprotein in essential arterial hypertensive patients. The purpose of our study was to measure the serum concentrations of Lp(a) and the main parameters of the lipid profile in a group of essential hypertensive patients not receiving pharmacological treatment and with no clinical signs of associated pathologies or organ damage. A total of 123 Caucasian essential arterial hypertensive patients (47 men and 76 women) were studied and compared with 89 controls (36 men and 53 women) matched in terms of age, sex, body mass index (BMI) and smoking habits. It was found that the hypertensive patients had higher plasma concentrations of Lp(a), total cholesterol (TC), triglycerides (TG) and very low density lipoprotein (VLDL-C) than controls (P < 0.01), with no differences in the plasma concentrations of Lp(a) between the two sexes. Only 10 hypertension patients and seven controls had plasma concentrations of Lp(a) of over 30 mg/dl. Lp(a) does not correlate with the main parameters of the lipid profile. We can confirm that hypertension and dyslipidaemia, which are two of the main risk factors for vascular diseases on an atherosclerotic basis, are often associated. However, higher plasma concentrations of Lp(a), albeit within the normal range, could be an independent risk factor for atherosclerosis, and could contribute towards increasing the incidence of cardiovascular disease in people with essential arterial hypertension.

Adult↗
PubMed1997

Prediction of ozone-induced FEV1 changes. Effects of concentration, duration, and ventilation.

The purpose of this analysis of previously published data was to identify a model that accurately predicts the mean ozone-induced FEV1 response of humans as a function of concentration (C), minute ventilation (VE), duration of exposure (T), and age. Healthy young adults (n = 485) were exposed for 2 h to one of six ozone concentrations while exercising at one of three levels. Candidate models were fitted to portions of the data and evaluated on the basis of their ability to predict the mean response of independent samples. A sigmoid-shaped model that is consistent with previous observations of ozone exposure-response (E-R) characteristics was identified and found to accurately predict the mean response with independent data. This model in a more general form may allow the prediction of responses under conditions of changing C and VE. We did not find that response was more sensitive to changes in C than in VE, nor did we find convincing evidence of an effect of body size upon response. We did find that response to ozone decreases with age. In summary, we have identified a biologically plausible, predictive model that quantifies the relationship between the ozone-induced change in FEV1, and C, VE, T, and age.

Adolescent↗
PubMed1997

Basal nitric oxide production is not reduced in patients with noninsulin-dependent diabetes mellitus.

Vascular disease is the leading cause of morbidity, disability and death in patients with noninsulin-dependent diabetes mellitus. Abnormalities in endothelium-derived nitric oxide (NO) have been demonstrated to be involved in the pathogenesis of vascular disease. By measuring hemodynamic responses to a NO synthase agonist or antagonist, previous studies have shown the presence of NO deficiency in patients with noninsulin-dependent diabetes mellitus, a method of assessing bioactive NO formation. However, direct biochemical evidence that this is the case, has not been produced. In vivo NO is metabolized into nitrate, an end breakdown product of NO, which can be used as an index of endogenous NO formation. To investigate further whether decreased basal synthesis of NO may be a major cause of endothelium-mediated vascular dysfunction in patients with noninsulin-dependent diabetes mellitus, the plasma nitrite/nitrate levels of 15 patients were examined and compared with 13 normal controls. The results showed that in basal conditions plasma nitrite/nitrate levels were not reduced in diabetic patients compared with normal controls (37.3 +/- 14.7 versus 29.4 +/- 8.6 mumol/l). It was concluded that in noninsulin-dependent diabetes mellitus patients, endothelium-derived basal NO formation is not impaired. This study, taken with previous observations, suggests that factors other than diminished basal NO production, such as reduced bioavailability of NO probably due to the augmented production of superoxide anion with subsequently increased inactivation of NO, contribute to the high incidence of vascular disease in patients with noninsulin-dependent diabetes mellitus.

Aged↗
PubMed1995

Proportion of moderately exercising individuals responding to low-level, multi-hour ozone exposure.

The purpose of this study was to describe the proportion of moderately exercising individuals experiencing significant respiratory responses to low-level, multi-hour ozone exposure as a function of ozone concentration and exposure duration. Sixty-eight healthy, nonsmoking adults, ages 18 to 34 yr, underwent two or more 6.6-h exposures to 0.0, 0.08, 0.10, or 0.12 ppm ozone. Five hours of exercise was performed during exposure, and lung function was measured before exposure and following each hour of exposure. For each combination of concentration and duration, each individual was determined to either have or not have experienced a 10% or greater decrement in FEV1. A logistic function was used to model the proportion of individuals experiencing such a decrement as a function of concentration and exposure duration. Bootstrap 90% confidence intervals (CIs) were calculated around the predictions. The model was found to give predictions that were in good agreement with observed data. The lowest level of exposure (C x T) for which the 90% CI excluded zero was approximately 0.2 ppm-h. For exposure to 0.12 ppm ozone for 6.6 h, 47% (90% CI = 30 to 65%) of exposed individuals were predicted to experience a 10% decrement in FEV1. A greater proportion of younger adults than of older adults were found to experience a given effect for a given exposure.

Adolescent↗
PubMed1990

[Netilmicin in a single daily dose for treatment of systemic infections].

The Authors report the results obtained in 35 patients of either sex suffering from various systemic infections and treated with netilmicin. Netilmicin has been intramuscularly administered in once daily dose of 4.5 mg/kg (mean daily dose 294.3 mg) for a mean duration of 17.8 days. The clinical resolution of the infections has been achieved in 97.1% (34 patients) of the study population; only one patient showed failure. Thirty-three of the 35 baseline causative pathogens have been eradicated. The local and systemic tolerability was good. The serum pharmacokinetics showed bactericidal levels of netilmicin and no serum accumulation.

Adult↗
PubMed1986

[Isolation of Flavobacterium odoratum from human matter].

Described the most important taxonomical, bacteriological, clinical and epidemiological aspects of microorganisms of Flavobacterium genus, the author refer about 8 strains of Flavobacterium odoratum isolated from urine (6), sputum (1), surgical exudate (1). In some cases, etiopathogenetic possible correlation between isolates and clinical disease discussed, the author emphasizes the large antibiotic resistance kind of this species of microorganism non fermenter.

Bacteriuria↗
PubMed1985

In vitro antibacterial activity of ceftizoxime.

During 1983, the antibacterial activity of ceftizoxime has been tested in vitro against 325 strains of Enterobacteriaceae, Streptococcaceae, Micrococcaceae, Pseudomonaceae and Acinetobacter sp. isolated from material of human origin (blood, urine, faeces, sputum, various exudates). Except for S. faecalis and some strains of P. rettgeri, P. aeruginosa, A. calcoaceticus, Staphylococcus spp. all the strains examined were found to be sensitive to the antibiotic, whose MIC was 0.05-1.5 micrograms/ml in the great majority of cases. For 72 ceftizoxime-sensitive strains the MBC/MIC ratio was nearly always under 4:1, confirming the drug's bactericidal activity. On strains of Enterobacteriaceae (E. coli, K. pneumoniae, S. marcescens, S. typhimurium) MIC of ceftizoxime achieved a minimum bactericidal time (MBT) between 3 and 4 hours of bacteria-antibiotic contact, and bacterial survival percentages were, in any case, very low as early as the 1st hour.

Bacteria↗
PubMedDate not supplied

[Hemolytic properties of Escherichia coli strains isolated from cases of urinary tract infection and enteropathy].

Different strains of E. coli, that were isolated during years 1986-1990 from 217 urine samples in patients with asymptomatic bacteriuria, cystitis, cysto-pyelitis and pyelonephritis, appeared to be more frequently haemolytic (34.5%) than strains of E. coli isolated from faecal samples in patients with acute enteropathy. It was confirmed that the haemolysin production occurs during log -phase of bacterial growth. The degree of haemolysis can vary widely according to the strain involved. Agglutination tests, using 53 O-antiserum, showed a great variety of serogroups. Some of them (04, 018, 022) are prevalent among the haemolytic strains isolated from urine; some others (055, 0111, 075) are prevalent among the anhaemolytic strains isolated from urine and faeces.

Agglutination Tests↗
PubMedDate not supplied

[Various biotypes of Escherichia coli: their correlation with antibiotic resistance].

The antimicrobial susceptibilities of 572 strains of Escherichia coli were evaluated. The strains were divided according to the biotypes and the differences between the strains towards various antibiotics were examined. We found a correlation between biotype and antibiotype. This correlation lead us to think of a possible existence of more resistant biotypes than others. Now we are doing other studies in order to show if this correlation is constant during time and if similar differences are present for other microorganisms, as well.

Anti-Bacterial Agents↗