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Biomedical subjects

L Tatò

Publications and source records attributed to L Tatò.

At least 55 records · Page 3Linked to original sources
PubMed1999

Leptin concentration in newborns' cord blood: relationship to gender and growth-regulating hormones.

AIMS: To verify if plasma leptin concentrations of newborns at birth differ significantly between sexes; and to investigate the potential interactions between plasma leptin and growth-regulating hormones at birth. SUBJECTS: 98 healthy newborns (48 male, 50 female) were studied. Leptin, insulin, cortisol, insulin-like growth factor-1 (IGF-1), testosterone, and sex hormone binding globulin (SHBG) concentrations were measured from venous blood collected from the umbilical cord vein immediately after birth. RESULTS: The serum leptin concentration of newborns averaged 8.05(0.5) ng/ml. Females had significantly (P<0.005) higher serum leptin values than males [9. 6(0.8) vs 6.0(0.6) ng/ml]. IGF-1 was significantly (P<0.05) higher in females than in males [87(4) vs 74(5) microg/l], whereas SHBG was slightly lower [29(1) vs 33(2) nmol/l]. Insulin, cortisol, and testosterone serum concentrations were not statistically different between the sexes. Among the variables examined, birth weight (expressed as Z-score of weight) and insulin showed the highest degree of relationship with serum leptin in newborns (r=0.48 and r=0.31 respectively, P<0.001). Multiple regression analysis showed that Z-score of birth weight, gender and cortisol were able to account for approximately 44% of inter-individual variability of serum leptin concentrations in newborns. CONCLUSIONS: Female newborns have significantly higher serum leptin concentrations than males. Insulin, IGF-1, testosterone, and SHBG did not independently affect leptin inter-individual variability when gender, Z-score of body weight, and cortisol were taken into account. Other factors may be involved in the differences in circulating leptin concentrations between the sexes in newborns.

Female↗
PubMed1999

Fat oxidation and adiposity in prepubertal children: exogenous versus endogenous fat utilization.

Fat balance plays an important role in fat mass regulation. The mechanisms by which fat intake and fat oxidation are controlled are poorly understood. In particular, no data are available on the origin, i.e. exogenous (meal intake) or endogenous (adipose tissue lipolysis), of fat oxidized during the postprandial period in children and the proportion between these two components. In this study we tested the hypothesis that there is a relationship between adiposity and the oxidative fate of fat taken with a mixed meal in a group of 15 children with a wide range of fat mass (9-64%). The combination of stable isotope analysis ([13C] enriched fatty acids added to a mixed meal) and indirect calorimetry allowed us to differentiate between the exogenous and endogenous resting fat oxidation rate over the 9-h postprandial period. During the 9 hours of the postprandial period, the children oxidized an amount of fat comparable to that ingested with the meal [26.8 (+/-2.31) g vs. 26.4 (+/-2.3) g, respectively, P = ns]. On average, exogenous fat oxidation [2.99 (+/-3.0) g/9 h] represented 10.8% (+/-0.9) of total fat oxidation. Endogenous fat oxidation, calculated as the difference between total fat oxidation and exogenous fat oxidation, averaged 23.4 (+/-1.9) g/9 h and represented 88.2% (+/-0.9) of total fat oxidation. Endogenous fat oxidation as well as exogenous fat oxidation were highly correlated to total fat oxidation (r = 0.83, P < 0.001; r = 0.84, P < 0.001, respectively). Exogenous fat oxidation expressed as a proportion of total fat oxidation was directly related to fat mass (r = 0.56, P < 0.03), while endogenous fat oxidation expressed as a proportion of total fat oxidation was inversely related (r = -0.57, P < 0.03) to the degree of adiposity. The enhanced exogenous fat oxidation observed when adiposity increases in the dynamic phase of obesity may be viewed as a protective mechanism to prevent further increase in fat mass and hence to maintain fat oxidation at a sufficient rate when the body is exposed to a high amount of dietary fat, as typically encountered in obese children.

Adipose Tissue↗
PubMed1999

Prevention of bone demineralization by calcium supplementation in precocious puberty during gonadotropin-releasing hormone agonist treatment.

We have previously demonstrated a negative impact on peak bone mass in girls with precocious puberty treated with GnRH agonist (GnRHa). Several studies have shown that a high calcium intake positively influences bone mass in prepubertal girls and leads to a higher peak bone mass. The aim of this study was to evaluate the effect of calcium supplementation in girls with precocious puberty during GnRHa treatment. Forty girls affected by true central precocious puberty and treated with the GnRHa triptorelin were studied for 2 yr. After diagnosis, the patients were randomly assigned to three groups: group A, treated only with GnRHa; group B, treated for 12 months solely with GnRHa and then supplemented with calcium gluconolactate/carbonate (1 g calcium/day in two doses) for 12 months; and group C, treated from the beginning with combined GnRHa and calcium. Bone mineral density (BMD) at the lumbar spine was measured by dual energy x-ray absorptiometry at the beginning of the study and after 12 and 24 months and was expressed as the calculated true volumetric density (BMDv) in milligrams per cm3. Group A showed a decrease in absolute BMDv levels, in SD score for chronological age (CA), and even more in SD score for bone age (BA). Group B showed the same behavior during the first year, but this trend was reversed in the second year, when calcium supplementation was added to GnRHa treatment. Group C showed an increase in absolute BMDv levels and in SD score for CA and BA. BMDv variations (expressed as absolute values, SD score for CA, and SD score for BA) became statistically significant at 24 months between groups C and A (P = 0.036, P = 0.032, and P = 0.025, respectively). The behavior of the lumbar spine BMDv in the three groups is consistent with a positive effect of calcium supplementation during GnRHa treatment. In calcium-supplemented patients, the normal process of bone mass accretion at puberty is preserved despite GnRHa treatment. Therefore, the reduction in BMD during GnRHa treatment in girls with precocious puberty is at least completely reversible and preventable if calcium supplementation is associated from the beginning.

Body Height↗
PubMed1998

Determination of thyroxine in the hair of newborns by radioimmunoassay with high-performance liquid chromatographic confirmation.

Hair analysis is often used in forensic toxicology to study, retrospectively, chronic exposure of individuals to drugs, and consequently newborn hair may become an ideal sample to study intrauterine exposure to xenobiotics as well as to endogenous compounds. As a tool to investigate a supposed maternal thyroxine (T4) supply to the congenital hypothyroid fetus, we devised to use the analysis of T4 extracted from newborn hair. In the present paper, the analytical method based on T4 extraction from hair followed by a radioimmunoassay is described. To verify the nature of the T4-like immunoreactive material present in newborn hair, it was further studied by HPLC fractionation with radioimmunoassay of the eluted fractions. On the basis of a clear correspondence between retention times of T4 standard and T4-immunoreactive compound extracted from hair, we assigned this immunoreactive material to T4. Then, we determined T4 hair concentrations in 19 control newborns at birth and 12 congenital hypothyroid infants at 22 days of life. Values obtained from hypothyroid infants (31.47+/-8.8 pg/mg(hair), mean+/-S.D.) were not significantly lower than those obtained from healthy newborns at birth (36.10+/-13.2 pg/mg(hair)). Such results are in agreement with the hypothesis of a maternal supply of thyroxine to the fetus through placental crossing.

Chromatography, High Pressure Liquid↗
PubMed1998

Evaluation of growth hormone bioactivity using the Nb2 cell bioassay in children with growth disorders.

The Nb2 cell bioassay could be a useful tool for evaluating human growth hormone (hGH) bioactivity, but is not specific for hGH since it relies on the ability of the hormone to produce effects by cross-reacting with the lactogenic receptor on Nb2 cells. We studied the biological activity of both endogenous and exogenous hGH in short patients using the Nb2 bioassay after inhibiting the mitogenic effect of the other lactogenic hormone, that is human prolactin (hPRL), by adding a specific antibody against hPRL to each assay. The in vitro study showed a significant (p<0.0001) increase in Nb2 cell proliferation when increasing concentrations of highly purified hGH were added to the cell culture. A complete inhibition of Nb2 cell replication was observed after adding a specific antibody against hGH. The in vivo study showed a significantly (p<0.0001) lower hGH bioactivity (4.90+/-0.28 ng/ml) evaluated during stimulation tests in 9 children with total idiopathic GH deficiency, mean age 9.25+/-1.99 years, in comparison with that found in 11 short children with normal growth velocity, mean age 8.22+/-1.41 years (12.25+/-1.19 ng/ml). Likewise, serum GH levels measured by immunofluorometric assay IFMA in the same serum samples were significantly (p<0.001) lower in the 9 GH-deficient (1.97+/-0.37 ng/ml) than in the 11 short children (21.85+/-2.71 ng/ml). Moreover, we evaluated GH concentrations using both IFMA and the Nb2 cell bioassay in serum samples collected from another 11 idiopathic GH-deficient children, mean age 10.71+/-1.18 years, before and then, 6 and 24 hours following the 1 st injection of r-hGH (0.1 IU/kg sc). Serum GH values measured by both IFMA and Nb2 bioassay significantly (p<0.0001) increased 6 hours after r-hGH administration and decreased to reach basal levels after 24 hours. In conclusion, the Nb2 cell bioassay with minor modifications seems to provide a specific and sensitive assessment of hGH bioactivity.

Animals↗
PubMed1998

[Growth hormone deficiency. Treatment with growth hormone and body composition].

Increased fat mass, decreased lean mass, muscular mass and bone mineral density are characteristic of the body composition in GH deficiency, GH treatment reverses these abnormalities. Body composition was determined in 20 young adults with GHD diagnosed in childhood, whose GH treatment was stopped 1 year earlier. Reevaluation of GH secretion in these patients showed that 12 remained GH deficient (confirmed GHD) while eight recovered normal GH secretion (transient GHD). One year after stopping the GH treatment, patients with confirmed GHD showed an increased fat mass as compared with value at the end of the treatment; in addition a decreased bone mineral content was observed in the patients with low physical activity. There was no increased fat mass in transient GHD; however, these patients presented with low bone mineral content, as previously reported in adults with history of delayed growth and adolescence.

Adolescent↗
PubMed1998

[Somatotropin function in term and premature newborns during the first month of life].

Neonatal somatotropic function is characterized by a discrepancy between elevated growth hormone (GH) levels and low IGF I levels. This study aimed at explaining this discrepancy, particularly to examining if it could result from low GH bioactivity. Serum concentrations of bioactive GH (bio GH), GH measured by radioimmunoassay (riGH), GH binding protein (GHBP), IGF I and IGF binding proteins (IGFBP) were determined in 27 premature and term newborns during the first month of life. At day 4, riGH and bio GH concentrations were elevated in both premature and term newborns as compared with normal prepubertal children; GHBP and IGF I levels were low, with a positive correlation with gestational age (P < 0.001). There was a positive correlation between GHBP and IGF I levels. IGFBP-1 and IGFBP-2 levels were elevated and negatively correlated with gestational age (P < 0.005). IGFBP-3 levels were within the range of prepubertal children values and positively correlated with gestational age (P < 0.005). During the first month, riGH and bio GH levels decreased in all infants, while IGFI levels increased in premature infants only, and GHBP levels in term infants only. The elevated levels of bio GH during the first days of life appear to be related to the low levels of IGF I due to a reduced number or function of GH receptors. In premature infants the decrease in GH levels observed afterwards appears to be secondary to the increase in IGF I levels. In term infants, in the absence of increase in IGFI levels other(s) factor(s) seem(s) to be involved.

Age Factors↗
PubMed1998

Influence of diet, physical activity and parents' obesity on children's adiposity: a four-year longitudinal study.

OBJECTIVE: To assess the relationships between diet, body composition, physical activity, parents' obesity and adiposity in children at the age of 8 y and four years later. STUDY DESIGN: Prospective observational study of anthropometric measures initiated in 1992, follow-up examination in 1996. METHODS: 112 prepubertal (age: 8.6 +/- 1.0 y) children were studied. Energy and nutrient intakes were assessed by diet history, body composition by anthropometry and physical activity, by a questionnaire. Obesity was defined as relative body mass index (BMI) (rel BMI) > 120%, where rel BMI = (BMI/BMI at 50th centile for age and gender) x 100. RESULTS: Prevalence of obesity was not statistically different at baseline (22.3%) than four years later (19.8%): rel BMI at the age of 8 y was positively self-related with rel BMI at the age of 12 y (r = 0.73, P < 0.001). After four years, eight (32%) obese children became non obese and five (6%) non obese children became obese. Multiple regression analysis (stepwise procedure) revealed that, in the final equation, the mother's BMI and TV viewing (independent variables) accounted for 17% of the children's rel BMI variance at the age of 8 y (R = 0.42, P < 0.001) while the parents' BMIs accounted for 13.5% of the children's rel BMI variance at the age of 12 y (R = 0.37, P < 0.001). Other variables such as total energy intake, nutrient intake percentage and amount of physical activity, were all rejected. An autoregressive unbalanced measures model regression analysis recognised the mother's and father's BMIs as the only variables able to predict rel BMI in the children (mother's BMI coeff. 2.53 (s.e.m. 0.26), P < 0.0001; father's BMI coeff. 2.07 (s.e.m. 0.23), P < 0.0001). A multivariate logistic regression analysis was also performed. The children who participated in the follow-up, were divided into two groups based on the positive or negative change in the rel BMI between final and baseline measurements. Of all the variables considered, only rel BMI at baseline was selected in the final equation. Other variables such as age, gender, energy and nutrient intake, TV viewing and amount of physical activity, as well as the parents' BMI, were all removed. CONCLUSIONS: The parents' obesity was the main risk factor for obesity in this group of children. Sedentary behaviour (TV viewing) was independently associated with overweight at the age of 8 y. Physical activity and energy and nutrient intakes did not significantly affect the change in rel BMI over the four-year period when the parents' obesity was taken into account.

Analysis of Variance↗
PubMed1997

Growth hormone bioactivity and levels of growth hormone, growth hormone-binding protein, insulinlike growth factor I, and insulinlike growth factor-binding proteins in premature and full-term newborns during the first month of life.

OBJECTIVE: To assess the pattern of growth hormone bioactivity (GH-BIO) and the levels of GH-binding protein (GH-BP), insulin-like growth factor I (IGF-I), and insulin-like growth factor-binding proteins (IGFBPs) in the first month of life in premature and full-term (FT) newborns. PATIENTS AND METHODS: Serum samples were collected from 9 premature newborns who were small for gestational age, 18 premature newborns who were of appropriate size for gestational age, and 20 FT newborns on the 4th and 30th days of life to evaluate the GH-BIO using the Nb2 cell bioassay, the GH levels using a radio-immunoassay (GH-RIA), and the levels of GH-BP, IGF-I and IGFBPs. RESULTS: On day 4, the GH-RIA and GH-BIO values were increased in all newborns (P < .05) compared with values in the prepubertal control subjects. The GH-BP levels were low in all newborns, with the lowest values (P < .05) found in the premature newborns and positively correlated with gestational age (P < .001). The IGF-I levels were also low, with lower values (than those found in the FT newborns) (P < .005) found in the premature group and positively correlated with the GH-BP levels (P < .001) and gestational age (P < .001). The levels of IGFBP-1 and IGFBP-2 were high, with higher values found in the premature newborns than in the FT newborns (P < .05) and negatively correlated with gestational age (P < .005). The IGFBP-3 level was lower in the premature (P < .05) than in the FT newborns and positively correlated with gestational age (P < .005). During the first month of life, the GH-RIA and GH-BIO values were significantly decreased in all newborns (P < .001), while the IGF-I level was increased in the premature newborns (P < .005). The GH-BP levels were increased only in the FT newborns (P < .001). CONCLUSIONS: The elevated bioactive GH level seen in the first few days of life seemed to be attributable to a low IGF-I level secondary to a decreased number and/or function of the GH receptors. The decrease in the serum GH level observed thereafter seemed to be secondary to an increase in the IGF-I level in the premature newborns; however, other factors may have been involved in the FT newborns in whom no increase in the IGF-I level was observed.

Aging↗
PubMed1997

Growth deficiency in polytransfused beta-thalassaemia patients is not growth hormone dependent.

OBJECTIVE: Growth deficiency is commonly seen in polytransfused beta-thalassaemia patients, especially in adolescence. It is not completely dependent on the lack of their pubertal growth spurt. GH impairment at different levels (hypothalamic or pituitary) and/or a reduced IGF-1 synthesis have been suggested the main causes of stunted growth in these patients. We evaluated the relationship between GH reserve and growth in short beta-thalassaemia patients. PATIENTS: Twenty-nine short patients (height < -1.8 SDS for chronological age) were divided into two groups (low and normal responders) on the basis of their GH peak during insulin and clonidine tests (< or = and > 20 mU/l, respectively). All but one low responders underwent the GHRH test to exclude the impairment of somatotroph function and in eight of them an IGF-1 generation test was also performed. The two groups were compared with each other with respect to growth (height deficiency, height velocity, bone age and bone delay), haematological characteristics (serum ferritin levels, age at the start both of low (subcutaneous) s.c. infusion of desferrioxamine and of transfusional therapy) and serum IGF-1 and IGF-1 binding protein 3 levels. RESULTS: Thirteen patients (45%) (11 males, two females) were low responders, all but two having serum IGF-1 < 5th centile (< 0.1 centile in 42%); the GHRH test excluded the impairment of somatotroph function in 8/12. Height deficiency, serum ferritin levels, and age at the start of s.c. chelating therapy did not differ in low compared to normal responders. Height was negatively correlated both with the age at the start of s.c. chelating therapy and with serum ferritin levels. CONCLUSION: The reduction of GH reserve, more frequently due to a hypothalamic than to a pituitary dysfunction, is frequent in polytransfused beta-thalassaemia patients, especially in males. The height function is not related to the GH reserve, given the current methods for testing GH reserve. Late start of s.c. chelating therapy as well as haemosiderosis seem to play a role in the height deficiency, but not in GH reserve. Impairment of GH secretory reserve, therefore, cannot be considered the main cause of height deficiency in these patients.

Adolescent↗
PubMed1997

[Graves' disease].

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Antithyroid Agents↗
PubMed1996

Postnatal variations of growth hormone bioactivity and of growth hormone-dependent factors.

OBJECTIVE: To evaluate whether the low insulinlike growth factor I (IGF-I) levels that are observed in the neonate depend on the biological inactivity of the molecular forms of growth hormone (GH) or on the immaturity of the hepatic GH receptors during the early postnatal period. MATERIALS AND METHODS: Serum samples were collected from 60 normal full-term neonates on day 5 and at 1 and 4 months of age to evaluate the GH concentrations by using both an immunofluorometric assay and Nb2 cell bioassay, as well as the GH-binding protein, IGF-I, and IGF-binding protein 3 values by radioimmunoassay. RESULTS: Five-day-old neonates showed significantly higher (P < .001) mean +/- SEM GH levels that were measured by using the immunofluorometric assay (27.22 +/- 1.62 micrograms/L) and Nb2 cell bioassay (3.56 +/- 0.14 U/mL) compared with those levels in 11 prepubertal children who were studied as control subjects (1.26 +/- 0.28 micrograms/L and 0.74 +/- 0.08 U/mL, respectively). At 1 and 4 months of age, GH values that were measured by using both the immunofluorometric assay (9.15 +/- 0.89 and 2.58 +/- 0.32 micrograms/L, respectively) and Nb2 cell bioassay (2.52 +/- 0.11 and 1.71 +/- 0.15 U/mL, respectively) were decreased significantly (P < .001). In 5-day-old neonates, we observed significantly lower (P < .001) serum GH-binding protein (9.73% +/- 0.42%), IGF-I (67.63 +/- 5.20 ng/mL), and IGF-binding protein 3 (1.46 +/- 0.17 mg/L) concentrations compared with those in the prepubertal children (30.74% +/- 2.01%, 210 +/- 25 ng/mL, and 3.08 +/- 0.22 mg/L, respectively). At 1 month of age, serum GH-binding protein (16.00% +/- 0.70%) and IGF-binding protein 3 (2.96 +/- 0.30 mg/L) values were increased significantly (P < .001), while IGF-I levels (72.55 +/- 7.6 ng/mL, P = .09) were not increased. Serum IGF-I values were increased significantly (P < .005) at 4 months of age (97.94 +/- 9.68 ng/mL). CONCLUSION: The interaction of bioactive molecular forms of GH with the increased hepatic GH receptors induces the rise in postnatal IGF-I levels in early infancy.

Age Factors↗
PubMed1996

Epidemiological survey of goiter and iodine deficiency in Veneto region.

The aim of this paper was to determine goiter prevalence and urinary iodine excretion in the Veneto region. It is known since ancient times that goiter prevalence has affected mainly the mountainous areas in Italy. An extensive epidemiological survey was carried out in school-aged children, visiting 5,439 students and testing 1,883 urinary samples. A goiter prevalence of 8.8% was found in the Region; 7.7% of grade 1A and 1.1% of grade 1B respectively; in the pre-mountainous area the prevalence was higher than 10% (11.7% in the Treviso area and 12.7% in the Vicenza area). Urinary iodine excretion was less than 100 mcg/cr in about 45% of all examined children, with a peak of 20% under 50 mcg/cr in the Vicenza district. According to the WHO criteria, the goiter prevalence in the Veneto area can be considered under the limits of epidemic standards. Nevertheless we feel that in light of the urinary data a prophylaxis with iodine added salt should be recommended in any case.

Child↗
PubMed1996

Gonadal function and response to growth hormone (GH) in boys with isolated GH deficiency and to GH and gonadotropins in boys with multiple pituitary hormone deficiencies.

OBJECTIVE: [corrected] To evaluate spermatogenesis in patients with isolated GH deficiency and multiple pituitary hormone deficiencies. DESIGN: Treatment of isolated GH-deficient patients with recombinant human GH (weekly dose of 0.7 IU/kg) for 5.3 +/- 0.4 (mean +/- SD) years and cotreatment of multiple pituitary deficient patients with GH at the same dosage for 8.0 +/- 0.4 years and hCG (2,000 IU, three times per week) and hMG (500 IU, two times per week) for 13.7 +/- 1.1 months. SETTING: Endocrine Pediatric Unit. PATIENTS: Eight patients affected by isolated GH deficiency and seven by multiple pituitary hormone deficiencies. MAIN OUTCOME MEASURES: Serum LH, FSH, and T, testicular volume, semen volume, density, count, and motility. RESULTS: Patients with isolated GH deficiency completed their pubertal development in 19.0 +/- 3.5 months and patients with multiple pituitary hormone deficiencies in 13.7 +/- 1.1 months. At the end of puberty, the two groups of patients had similar testicular volume, penis size, sperm concentration, motility, and morphology, although T levels and seminal volume were lower in isolated GH-deficient patients than in multiple pituitary deficient patients. CONCLUSIONS: The two groups of patients, treated specifically for their identified hormonal deficiencies, in the end had similar satisfactory reproductive results.

Adolescent↗
PubMed1996

[Precocious puberty].

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Antineoplastic Agents, Hormonal↗
PubMed1995

Use of the gonadotropin-releasing hormone agonist triptorelin in the diagnosis of delayed puberty in boys.

To differentiate gonadotropin deficiency from delayed puberty in teenage boys, 0.1 mg/m2 of triptorelin, a gonadotropin-releasing hormone agonist, was administered subcutaneously at 4 AM. Serum gonadotropins and testosterone levels were determined at baseline and 4 hours after the injection. The increase in blood gonadotropin and testosterone levels was significantly greater in patients with delayed puberty than in those with gonadotropin deficiency.

Adolescent↗