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Biomedical subjects

A Ferro-Luzzi

Publications and source records attributed to A Ferro-Luzzi.

99 records · Page 6Linked to original sources
PubMedDate not supplied

The estimation of body density in men: are general equations general?

Regression equations for estimating body density and fatness from anthropometric measurements are usually specific to the populations from which they are derived, owing to methodological and biological factors. Some equations are, however, regarded as having general validity for subjects of different ages, levels of fatness and fitness. In this study, five such general equations were tested by comparing estimated body density (Dest) with measured body density (Dmeas) in 138 European men employed in an Italian shipyard. Body density was measured by underwater weighing with the simultaneous determination of lung residual volume. Measurements were also made of height, weight, eight skinfolds, four circumferences and seven diameters by standard techniques. Dest from the five general equations were significantly different from Dmeas (P less than 0.001). New prediction equations for estimating D were drawn up by simple and multiple regression of various combinations of skinfolds expressed as individual skinfolds, sums, log sums and the quadratic form. Equations were drawn up on a validation sample (N = 92) and tested on a cross-validation sample (N = 46). The form of skinfolds and the combination selected made little difference to the SEEs and R2 but the inclusion of age resulted in lower SEEs. Stepwise multiple regression produced an equation incorporating thorax and triceps skinfolds and age with an SEE of 6 kg/m3 and R2 of 79%. The derived equations were successfully cross-validated, Dmeas and Dest were not significantly different, ryy' and SEE were similar to those of the validation sample. When the cross-validation sample was divided into two according to age, density or VO2 max, the derived equations were applicable to the upper and lower groups for age or physical fitness but not to the groups differing in fatness. These equations should be validated further on other samples by studies performed with due regard to the methodological factors, both technical and statistical, that may result in specificity. However, the poor performance of the general equations tested and the specificity for fatness of the derived equations suggest that biological factors may preclude the development of general prediction equations for body density.

Adult↗
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Body composition and body hydration in old age estimated by means of skinfold thickness and deuterium dilution.

In this study a group of 30 women and 30 men aged 60-90 years was examined. Body density was predicted from the sum of four skinfold thickness (SFT) as described by Durnin and Womersley (1974). Body composition, expressed as a percentage of total body weight as fat mass (FM) and fat free mass (FFM) was calculated by means of Siri's formula (Siri 1961). Total body water (TBW) was measured from the dilution of an oral deuterium dose and FFM calculated assuming a hydration of 73.2%. The FM% predicted from SFT showed a slight but not significant decreasing age trend from 28.3% to 25.4% in men, and from 40.3% to 37.8% in women. Body hydration (about 50% of body weight in men and 44% in women) remained constant throughout the age range. FFM obtained from TBW assuming a constant hydration of FFM, was found to be unchanged with age. FM% predicted from SFT was correlated with values obtained from TBW on an individual basis (R2 = 0.38; p less than 0.0001 in men and R2 = 0.31; p less than 0.002 in women), but the scatter was large. The Bland and Altman statistical analysis (Bland and Altman 1986) suggests that the discrepancy between the two estimates tends to be significantly more positive with increasing fatness of the subject. The assumption of a constant hydration of FFM between individuals and with advancing age was tested. The hydration of FFM was calculated as the ratio between TBW (from deuterium dilution) and FFM (estimated from SFT). The wide range of values (50% to 90%) suggests large inter-individual differences. The mean values were lower than commonly reported, and differed with age and sex. In men, FFM hydration steadily decreases with age from the 7th decade (70.2 +/- 7.7%) to the 10th decade (65.9 +/- 8.2%). Women showed higher average figures than those of men and a lower age-associated decline (72.5% and 68.5% respectively). Our results suggest that FFM hydration decreases with age, and this indicates the need to develop age-related correction factors in order to derive FFM from TBW in an elderly population.

Aged↗
PubMedDate not supplied

Determinants of nutritional status in hospital patients in Italy.

The prevalence of protein-calorie malnutrition (PCM) and micronutrient deficiency (MND) at the time of admission and discharge from hospital was evaluated in 91 patients consecutively admitted to the Surgery Clinic of the University Hospital of Rome. Anthropometric parameters and circulating levels of vitamins (A, E, C, B1, and B2) and visceral proteins [retinol-binding protein (RBP, prealbumin (PA), and transferrin] were measured. Twenty-one patients (23%) had moderate to severe PCM, and 70 patients (77%) had normal nutritional status (NNS) at admission. Two patients with PCM died in the hospital. At discharge, the prevalence of PCM was unchanged in the remaining 19 patients. Single or multiple MND was observed initially in 71% of patients with PCM and in 36% with apparently normal nutritional status. Despite vitamin supplementation, MND was present at the time of discharge in 73% of patients with PCM and 44% with NNS. Nutritional status at the time of admission was assessed in hospitals in six different Italian cities. The criterion for admission to the study was the diagnosis of chronic (greater than 1 yr duration) illness (excluding cancer and multiple organ disorders). Two hundred eighty-four patients (145 males, 139 females), ages 25-88 yr, were selected. The findings indicated a high prevalence of MND (64%). Also, in disorders that usually do not have significant alterations of digestion or absorption, such as uncomplicated cardiorespiratory disease, the prevalence of MND was high (9-38%). The prevalence of MND was not related to body mass index (BMI). PCM was more common among patients with chronic gastrointestinal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[A study of N/H2O ratios in Sprague-Dawley rats under variable conditions and its use for routine NPU determinations (author's transl)].

Nitrogen to body-water ratios were determined in a colony of rats of the Sprague-Dawley strain in order to investigate variations under variable conditions of age and diet. The study was conducted in order to verify the accuracy of body Nitrogen calculation from body-water determinations for the given colony under different experimental conditions. Only male animals were studied. The effect of age was studied for the intevals of 21, 28, 31, 42, 51, 84, and 126 days. N/H2O ratios were shown to increase exponentially with age within the range taken in consideration. Separate regression equations are given for 21 to 31 and for 31 to 51 day old animals relating the N/H2O ratio with age. The relationship between quality and quantity of protein of diets and the N/H2O ratio was investigated in 21 to 31 day old animals only. The N/H2O ratio was significantly higher in the animals fed the protein-free diet and diets with NPU less than 40. For these groups the factor 4.12 was obtained. Animals fed diets with NPU's ranging between 50 and 80 gave a factor of 3.94. For diets with NPU ranging from 50 to 80, the variation of the dietary protein level between 10 and 18% did not appear to influence the N/H2O ratio. NPU values calculated from analitically determined body Nitrogen were compared with NPU value calculated from body Nitrogen estimated using the established N/H2O ratios. The two sets of values are in good agreement supporting the use of the short-cut method for routine NPU determinations, given the appropriate factors are applied. It is recommended that such factors be experimentally determined for each own colony of rats.

Animals↗
PubMedDate not supplied

Pattern of thyroid hormones in mildly protein-deficient women in area endemic for goiter.

This study refers to 23 nonpregnant and 5 pregnant Ethiopian women living in a severely iodine-deficient area exposed to marginal chronic protein malnutrition. About half the study group exhibited goiter. The components of retinol circulating complex have been measured: transthyretin, retinol, and retinol-binding protein were 31 +/- 8 mg/dl, 36 +/- 6 micrograms/dl, and 3.1 +/- 0.6 mg/dl, respectively. No differences in circulating thyroid hormone pattern were found among goitrous and nongoitrous subjects. In nonpregnant women, the circulating thyroid hormone pattern was characterized by a low total T4 (TT4, 53 ng/ml), whereas free T4 (FT4, 0.5 ng/dl) was below the lower level of the range. Thyroid-stimulating hormone and FT3 were in the normal range, and TT3 was at the upper level of the range. The pregnant women exhibited the expected increase in total thyroid hormones (TT3 3.0 ng/ml, TT4 96 ng/ml), whereas the free fractions were equal to those of the nonpregnant subjects (FT3 2.5 pg/ml, FT4 0.6 ng/dl). In the whole group, the T3-T4 ratio was 3.4 x 10(-2), i.e., twice the normal ratio. No antibodies against thyroid structures were detected. These results indicate that the circulating thyroid hormone pattern of these marginally malnourished women differs from that reported for subjects with pure protein-calorie malnutrition or exposed to chronic iodine deficiency only. The main difference is that, even in the presence of low TT4 and FT4, the hypophysis-thyroid axis has apparently remained unchanged. The normal levels of TT3 and FT3, may account for the normal thyroid-hypophysis feedback.

Adult↗
PubMedDate not supplied

Use of PABA test to check completeness of 24-h urine collections in elderly subjects.

The p-aminobenzoic acid (PABA) test has been successfully used as an indicator of completeness of 24-h urine collection in field studies of the general population. Our study was designed to investigate its validity for elderly people. Urinary excretion of fractionated oral doses of PABA was measured in 21 young control subjects (19-39 yr old) and 356 elderly (60-89 yr old) men and women. PABA excretion over 24 h was lower in elderly than in control subjects. Subjects aged greater than or equal to 70 yr had a lower recovery of the PABA dose than subjects aged 60-69 yr over the first 24 h, followed by a higher recovery over the next 24-48 h. The cumulative 48-h recovery was similar in all age classes of elderly subjects. However, 48% of the elderly subjects had a cumulative PABA recovery below the conventional cutoff for completeness (85%). These subjects also had consistently lower creatinine output and urinary volume. The lower 24-h urinary PABA recovery over 70 yr of age is interpreted to reflect the delayed renal clearance of the marker substance and indicates that the PABA test is unsuitable for this age group. The low 48-h cumulative recoveries found in all age classes of the elderly are thought to be caused by small unreported losses, which are recurrent in free-living populations.

4-Aminobenzoic Acid↗