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Biomedical subjects

G Chiumello

Publications and source records attributed to G Chiumello.

At least 73 records · Page 4Linked to original sources
PubMed1997

Body composition assessed on the basis of arm circumference and triceps skinfold thickness: a new index validated in children by magnetic resonance imaging.

Fat and muscle areas can be calculated from equations on the basis of upper arm circumference (C) and triceps skinfold thickness (TS). These equations assume a circular limb and muscle compartment and a symmetrically distributed fat rim: total upper arm area (TUA) = C2/(4 pi), upper arm muscle area (UMA) = [C - (TS x pi)2]/(4 pi), and upper arm fat area (UFA) = TUA - UMA. This traditional method underestimates the degree of adiposity. We propose that the unrolled fat rim is a rectangle whose length = C and width = TS/2. The following new indexes are based on this assumption: upper arm fat area estimate (UFE) = C x (TS/2), and upper arm muscle area estimate (UME) = TUA - UFE. To validate these equations, areas were measured with magnetic resonance imaging (MRI) in 28 children aged 9-15 y (17 control subjects and 11 obese subjects). Correlations between MRI and UFA and MRI and UFE were similar (r = 0.96 for both correlations in the control group and r = 0.84 and 0.82, respectively, in the obese group), but the areas assessed by MRI (13.8 cm2) were closer to UFE (12.4 cm2) than to UFA (11.2 cm2) in the control group as well as in the obese group (MRI = 48.7 cm2, UFE = 46.6 cm2, and UFA = 38.5 cm2). The limits of agreement between MRI and anthropometry were 5.7 +/- 5.8 cm2 for UFA and 0.6 +/- 5.0 cm2 for UFE, showing that UFA is not acceptable in most cases, whereas UFE measurements are close to MRI measurements. In conclusion, UFE and UME are simple and accurate indexes to assess body composition. French reference values are available from 1 mo to 17 y of age.

Adipose Tissue↗
PubMed1996

Human growth hormone treatment in prepubertal children with achondroplasia.

We studied the effects of recombinant human growth hormone (GH) treatment in 6 prepubertal children with achondroplasia. The patients' age ranged from 2 11/12 to 8 5/12 years and the GH dose was of 0.1 IU/kg/day subcutaneously. Auxological assessments and bone age determinations were performed 6 months before, at the beginning, and after 6 and 12 months of therapy. The growth velocity increase during the whole year of treatment ranged from 1.1 to 2.6 cm/year in 3 patients while in the others no variation was detected. No side effects were observed during the trial apart from a slight advancement of bone age in two patients. MRI at the cervicomedullary junction and CT scan of the base of the skull did not show any variation of the dimensions of the foramen magnum at the end of the trial compared to baseline. Our study shows that r-hGH can safely increase short-term growth velocity in some but not all prepubertal children with achondroplasia. Our data confirm the individual variability in the response to the GH treatment.

Achondroplasia↗
PubMed1996

Association of IA-2 autoantibodies with HLA DR4 phenotypes in IDDM.

Insulin, glutamate decarboxylase (GAD) and the protein tyrosine phosphatase-like molecule IA-2 are major targets of humoral autoimmunity in insulin-dependent diabetes mellitus (IDDM). These autoantibodies are heterogeneous with respect to age and patient human leukocyte antigen (HLA) phenotype. We have previously demonstrated that GAD and IA-2 antibodies potentially identify different subsets of IDDM patients. The aim of this study was to determine whether GAD and IA-2 autoantibodies were associated with different HLA DR phenotypes. We studied 160 patients with IDDM onset before age 16 years. At disease onset serum was tested for GAD and IA-2 antibodies by immunoprecipitation by in vitro-translated 35S-methionine labelled recombinant proteins. IA-2 antibodies were significantly associated with HLA DR4: 67 (86%) of 78 patients with HLA DR4 vs 31 (38%) of 82 non-DR4 patients had IA-2 antibodies (Pc < 0.0001) and IA-2 antibody levels were higher in patients with HLA DR4 (Pc < 0.0001). In contrast, GAD antibodies were more prevalent (Pc < 0.05) and antibody levels highest (Pc < 0.01) in patients with HLA DR3 phenotypes. These data provide further evidence that, in IDDM, production and titre of major autoantibody specificities are associated with HLA class II alleles.

Alleles↗
PubMed1996

Impairment of growth hormone responsiveness to growth hormone releasing hormone and pyridostigmine in patients affected by Prader-Labhardt-Willi syndrome.

In order to evaluate the impairment of GH response in patients affected by Prader-Labhardt-Willi (PLW) syndrome, in 18 patients we studied GH response to clonidine and to GHRH + pyridostigmine, a cholinergic drug which enhances GHRH induced GH responsiveness in obese patients. After clonidine GH response was abnormal in 14/18 subjects (mean GH peak: 4.1 +/- 1.3 micrograms/l; area under curve: 208.1 +/- 74.2 micrograms/l.h) while all but 5 patients showed an inadequate GH response to GHRH + pyridostigmine (mean GH peak: 13.4 +/- 2.5 micrograms/l; area under curve: 903.4 +/- 171.0 micrograms/l.h). However, in the three patients with low adiposity index, GH response to GHRH + pyridostigmine was significantly higher than that observed in fatter subjects. In addition, GH response to GHRH + pyridostigmine was negatively correlated to age and adiposity index. In conclusion, our data are consistent with the hypothesis of the existence of a complex derangement of GH neuroendocrine regulation in these subjects.

Adolescent↗
PubMed1996

Congenital hypothyroidism: auxological retrospective study during the first six years of age.

We examined length, height and weight from birth to six years of age and head circumference during the first two years in 89 children with congenital hypothyroidism (CH). The patients were divided in two groups: children diagnosed by clinical criteria during the first year of life (group A) and children detected by neonatal screening (group B). Group A showed a complete catch up growth for height and weight 10 months after the beginning of the replacement therapy; to the contrary, group B did not show any difference for height and weight compared to normal standards. Head circumference, evaluated only in group B, was significantly higher in comparison with normal standards. When etiology of CH was taken into consideration, children with athyreosis showed a significantly lower length at birth and at three months of age and their growths curves normalized after institution of replacement therapy. In conclusion our data suggest a direct relationship between severity and duration of hormone deficiency and growth retardation and confirm that replacement therapy started within the first year of live in CH patients clinically diagnosed allows a catch up growth.

Body Height↗
PubMed1996

Point mutations in Italian patients with classic, non-classic, and cryptic forms of steroid 21-hydroxylase deficiency.

Seventy-three Italian patients affected by steroid 21-hydroxylase deficiency were studied by a PCR-allele-specific oligonucleotide protocol in order to evaluate the presence of eight known point mutations. The majority of chromosomes were found to carry point gene conversions normally present in the pseudogene. Within the classic form, the most common mutations were the splicing mutation A/C-655 to G in intron 2 (34.2%), the nonsense mutation C-1993 to T in exon 8 (10.8%), and the missense mutation T-999 to A in exon 4 (10%). Within the non-classic form, the missense mutation G-1683 to T was the most common (57.7%). Other mutations were either absent, such as the three clustered missense mutations T-1380, T-1383, T-1389 to A in exon 6, or very rare, like the 1761 + T in exon 7 and the C-2108 to T in exon 8. Family genotyping revealed the presence of ten asymptomatic parents carrying mutations in both chromosomes, thus identifying the gene defect in cryptic subjects. Interestingly, the same mutations were found in both symptomatic and asymptomatic forms.

Adrenal Hyperplasia, Congenital↗
PubMed1996

Bone density in young patients with congenital adrenal hyperplasia.

One of the major complications of glucocorticoid treatment is bone loss. 21-Hydroxylase deficiency is the most frequent inborn error of steroidogenesis, leading to congenital adrenal hyperplasia (CAH): synthesis of cortisol is impaired and replacement therapy is therefore mandatory. We studied the bone mineral density in a group of patients with congenital adrenal hyperplasia (CAH) on long-term glucocorticoid replacement therapy. We selected 30 Caucasian patients with CAH due to 21-hydroxylase deficiency (mean +/- SD age = 17.45 +/- 2.49 years). 22 patients had the classical CAH form and the remaining 8 had the nonclassical (late-onset) form. The mean duration of therapy was 15.20 +/- 4.04 years. Bone mineral density (BMD) was evaluated with a dual-energy X-ray absorptiometer. BMD was also measured in 73 healthy white volunteers of comparable age (17.35 +/- 2.99 years). BMD values of the spine (sBMD), total body (TBBMD), legs, and arms of CAH patients, adjusted for confounding variables (age, gender, body mass index), did not differ from those of control subjects (p = 0.86; p = 0.17; p = 0.06 and p = 0.26, respectively). sBMD and TBBMD values did not show relationships with the duration of treatment and the dose of corticosteroids. Patients with the classical form of CAH had bone density values comparable with those of patients with the nonclassical form (sBMD: p = 0.33; TBBMD: p = 0.97). Our data show that, despite long-term treatment with glucocorticoids, CAH patients have bone density values comparable with controls.

Absorptiometry, Photon↗
PubMed1996

Sleep and upper airway obstruction in children with achondroplasia.

OBJECTIVE: The features of achondroplasia, the most common form of dwarfism, includes short cranial base and midface hypoplasia; both abnormalities increased the risk of upper airway obstruction during sleep. The aim of our study was to evaluate sleep and respiratory function of children with achondroplasia and to differentiate central from obstructive apnea. We also wanted to correlate apneic events with foramen magnum stenosis. STUDY DESIGN: Sixteen children with achondroplasia (mean age, 4.7 years) were studied by noctumal polysomnography and brain computed tomography or magnetic resonance imaging. A comparison of sleep and respiratory findings was made between the study group and 25 children with adenotonsillar hypertrophy. RESULTS: The study revealed no significant difference between groups with respect to sleep architecture. We also found no relationship between apnea type and foramen magnum stenosis. Twelve children (75%) with achondroplasia had significant upper airway obstruction during sleep, with symptoms of continuous snoring and periods of brief obstructive apnea, hypopnea, or both. The mean apneahypopnea index (per hour of sleep) did not differ significantly between the two groups. However, the breathing rate during sleep was increased in children with achondroplasia. These findings indicate that the most important breathing disorder during sleep in children with achondroplasia is upper airway obstruction. CONCLUSION: We conclude that polysomnography with detailed scoring of breathing abnormalities is a useful tool in evaluating sleep-disordered breathing in children with achondroplasia.

Achondroplasia↗
PubMed1996

Influence of body composition on bone mineral content in children and adolescents.

Excess fat and fat-free mass have been extensively described in obese children, whereas few data about bone mineral content (BMC) variations are available in children. Dual-energy X-ray absorptiometry (DXA) allows a direct and accurate measurement of three body compartments (fat, lean, and BMC), subdivided into three regions (arms, trunk, and legs). The aim of our study was to evaluate the influence of body compartments on total BMC (TBMC) and regional BMC (RBMC) in obese and normal-weight subjects. Sixty-five obese and 50 normal-weight children and adolescents (age range: 5-18 y relative body weight: 160 +/- 23% and 101 +/- 12%, respectively), matched for sex and pubertal stage underwent a DXA total-body analysis. Obese subjects had significantly greater fat and lean compartments than normal-weight subjects (P < 0.0001). TBMC was larger in obese children (1930 +/- 670 g compared with 1480 +/- 490 g, P < 0.0001) as was RBMC (arms: 182 +/- 81 g compared with 151 +/- 65 g; trunk: 560 +/- 223 g compared with 433 +/- 169 g; legs: 788 +/- 341 g compared with 539 +/- 231 g, P < 0.0001). We found lean mass to be the best correlate with TBMC (r = 0.91 in obese and 0.94 in normal-weight children). Multiple-regression analysis confirmed lean mass as one of the major determinants of TBMC and RBMC in children. However, differences in TBMC and RBMC were no longer present after correction for age, sex, and body-composition variables. There were no differences in TBMC and RBMC between obese and normal-weight children after correction for the confounding variables age and sex.

Absorptiometry, Photon↗
PubMed1996

Urinary growth hormone excretion in children and adolescents with insulin-dependent diabetes mellitus.

Urinary growth hormone (uGH) excretion was evaluated in 96 type-1 insulin-dependent diabetic patients and 37 age-matched healthy subjects. The growth hormone concentration was measured by a solid-phase immunoradiometric assay on 3 consecutive overnight urine collections. uGH excretion was comparable between diabetic patients and healthy subjects: 10.9 (0.1-34.8) vs. 9.1 (2.6-34.5) pg/min. In both groups uGH excretion was lower in prepubertal than in pubescent or pubertal individuals (diabetic patients, H = 29.7, p = 0.001; healthy subjects, H = 10.4, p = 0.006). In diabetic patients uGH excretion was related to beta 2-microglobulin excretion (r = 0.308; p = 0.005) and to urinary albumin excretion (r = 0.230; p = 0.02) but it was independent of HbA1c and overnight glycemic values. The coefficient of variation of uGH excretion was higher in diabetic patients with respect to healthy subjects: 50 (3-141) vs. 28(3-100)% (p = 0.002). Among diabetic patients it was greater in prepubertal than in pubescent or pubertal patients (H = 13.7; p = 0.002); in contrast, it was independent of pubertal stage in healthy individuals (H = 2.4; NS). The coefficient of variation of uGH was not related to HbA1c, the duration of diabetes, the coefficient of variation of urinary albumin excretion and the coefficient of variation of beta 2-microglobulin excretion. In conclusion uGH excretion is comparable among diabetic patients and healthy subjects, but its day-to-day fluctuation is greater in the former than in the latter group. Renal function but not metabolic control can influence uGH excretion. The day-to-day fluctuation in uGH excretion is independent of metabolic control and renal function.

Adolescent↗
PubMed1996

Islet cell surface antibodies are more common in patients and relatives in areas and during seasons with high incidence of insulin-dependent diabetes mellitus.

Although existence of islet cell antibodies (ICA) is regarded as secondary to beta cell death, islet cell surface antibodies (ICSA) might play a role in the disease process. We have collected information from nine European clinics to determine whether ICSA are more common in diabetic children or their relatives in geographical areas or time periods of high incidence of insulin-dependent diabetes mellitus (IDDM). In Finland and Sweden ("North group") with a high incidence of IDDM during childhood, 36% of the patients were positive or weakly positive for ICSA at diagnosis compared with 24% in France (p = 0.1), 11% in Berlin-Vienna (p < 0.01), and 14% in Italy (p < 0.01). This difference was seen in all age groups but was most pronounced in the youngest (0-4 y). This geographical difference was also seen among family members of whom 46% were positive or weakly positive in the North group, 25% in France (p < 0.001), 21% in Berlin-Vienna (p < 0.001), and 16% in Italy (p < 0.001). Of several analyzed antibodies (ICA, gastric parietal cell, thyroglobulin, and thyroid microsomal), only ICSA showed simultaneous positivity in all family members (r = 0.32, p < 0.01). ICSA were most common in family members of patients with short (< 8 d) duration of symptoms (p < 0.05) and showed a similar seasonality, both in patients and relatives, as the incidence of IDDM. We conclude that the geographical difference in incidence of childhood IDDM in Europe may be associated to similar geographical differences in occurrence of ICSA both in newly diagnosed diabetic children and in their relatives. Simultaneous existence of ICSA in both patients and family members and a similar seasonality for ICSA and incidence of IDDM suggest that ICSA may reflect an ongoing disease process.

Autoantibodies↗
PubMed1996

Genetic homogeneity of autoimmune polyglandular disease type I.

Autoimmune polyglandular disease type I (APECED) is an autosomal recessive autoimmune disease (MIM 240300) characterized by hypoparathyroidism, primary adrenocortical failure, and chronic mucocutaneous candidiasis. The disease is highly prevalent in two isolated populations, the Finnish population and the Iranian Jewish one. Sporadic cases have been identified in many other countries, including almost all European countries. The APECED locus has previously been assigned to chromosome 21q22.3 by linkage analyses in 14 Finnish families. Locus heterogeneity is a highly relevant question in this disease affecting multiple tissues and with great phenotypic diversity. To solve this matter, we performed linkage and haplotype analyses on APECED families rising from different populations. Six microsatellite markers on the critical chromosomal region of 2.6 cM on 21q22.3 were analyzed. Pairwise linkage analyses revealed significant LOD scores for all these markers, maximum LOD score being 10.23. The obtained haplotype data and the geographic distribution of the great-grandparents of the Finnish APECED patients suggest the presence of one major, relatively old mutation responsible for approximately 90% of the Finnish cases. Similar evidence for one founder mutation was also found in analyses of Iranian Jewish APECED haplotypes. These haplotypes, however, differed totally from the Finnish ones. The linkage analyses in 21 non-Finnish APECED families originating from several European countries provided independent evidence for linkage to the same chromosomal region on 21q22.3 and revealed no evidence for locus heterogeneity. The haplotype analyses of APECED chromosomes suggest that in different populations APECED is due to a spectrum of mutations in a still unknown gene on chromosome 21.

Alleles↗
PubMed1995

Bone mineral metabolism and thyroid replacement therapy in congenital hypothyroid infants and young children.

Impairment of calcium metabolism and low bone density have been found in hypothyroid adults. We investigated the effect of thyroid replacement therapy on calcium metabolism and bone mineralization in congenital hypothyroid (CH) infants and children. One hundred and 16 Caucasian CH consecutive patients were studied and were grouped according to their age: 23 patients at diagnosis, 20 at 3 mo, 24 at 6 mo, 25 at 12 mo and 24 at 36 mo. Thyroid replacement therapy was started at an initial dose of 6-8 micrograms/kg/day of L-thyroxine, and then decreased progressively. Calcium, phosphorus, magnesium, alkaline phosphatase (AP), parathyroid hormone (PTH) and osteocalcin (BGP) were measured as calcium metabolism indices. Bone mineral content (BMC) was measured at the mid-portion of the right radius AP, PTH and BGP concentrations were significantly higher in subjects at 3 mo of age (p < 0.05). This rise coincided with the end of the period of maximum dosage of L-thyroxine. Mild asymptomatic hypercalcemia was observed in 20 patients. All the other indices did not differ between age groups. BMC values and BMC annual increment were not different from those calculated for age-matched controls. We found that L-thyroxine replacement therapy does not alter bone mineralization of CH infants and children. Only a transitory increase of osteoblastic function was observed after the first few months of therapy.

Bone Density↗
PubMed1995

Adrenarche does not occur in treated patients with congenital adrenal hyperplasia resulting from 21-hydroxylase deficiency.

OBJECTIVE: There have been few studies of adrenarche in patients with congenital adrenal hyperplasia (CAH). We have therefore sought to detect the onset of adrenarche in CAH patients and to investigate whether its evolution was influenced by the severity of the disease, the age at the onset of substitution therapy, or both. DESIGN AND PATIENTS: Sixteen female CAH patients were studied longitudinally for 4-11 years. They were all given substitution therapy and treatments were well controlled as judged by repeated hormonal evaluations. The patients were divided into two groups: group A consisted of 10 girls with a severe classic (congenital) form, while group B included 6 girls presenting with a non-classic form. MEASUREMENTS: Circulating levels of dehydroepiandrosterone sulphate (DHEAS), were determined as an indicator of adrenarche. Hormonal assessments included measurements of 17-hydroxyprogesterone (17-OHP), testosterone, ACTH and plasma renin activity. All were estimated by conventional specific assays. RESULTS: Mean levels were analysed in consecutive two-year age periods. In group A, DHEAS levels were significantly lower at any age than in control subjects, and lower than in patients with non-classic CAH. DHEAS levels showed no increment with age. In group B, plasma DHEAS levels were surprisingly high for the age at the time of diagnosis, declining gradually on substitution therapy, although they remained somewhat higher than in group A. CONCLUSIONS: The high DHEAS levels observed in untreated girls of group B are probably the result of chronic hypersecretion of ACTH. Under well controlled, non-suppressive substitution therapy, patients with congenital adrenal hyperplasia showed no rise in DHEAS levels at the physiological age of adrenarche whatever the degree of the enzyme defect and whatever the age at onset of therapy.

17-alpha-Hydroxyprogesterone↗
PubMed1995

Prevalence and correlates of obesity in insulin dependent diabetic patients.

The prevalence of obesity, according to sex and pubertal stage, and the correlations between obesity and metabolic data were investigated in 286 diabetic patients (164 boys, 122 girls) with mean (SD) age 15.3 (3.2) years and mean (SD) duration of diabetes 7.5 (4.1) years. Prevalence of obesity according to the body mass index (BMI) criteria was 6.3%. Girls were more often obese than boys but the prevalence approached statistical significance only for the BMI criteria, at 9.8% v 3.7% (chi 2 = 3.5; p = 0.06); obesity was independent of pubertal stage. Distribution of BMI values of diabetic girls was skewed towards the high centiles of the INSERM tables: < 25th centile, 8.6%; 25th-50th centile, 17.3%; 50th-75th centile, 25.9%; > 75th centile, 48.2% (chi 2 = 19.17, p < 0.0005). BMI values of diabetic boys were homogeneously distributed. Age, duration of diabetes, insulin requirement, daily number of insulin injections, and metabolic control (HbA1c) were comparable in obese and non-obese diabetic patients. Moreover metabolic control and insulin requirements were comparable between diabetic patients with BMI above and below the 50th centile of the INSERM tables after matching for sex. In conclusion the prevalence of obesity in diabetic children and adolescents is quite similar to the prevalence reported in their non-diabetic peers. Obesity and BMI excess correlate with female gender but are independent of insulin requirement and metabolic control.

Adolescent↗
PubMed1995

Relative expansion of extracellular water in obese vs. normal children.

This preliminary communication reports data regarding the distribution between intracellular (ICW) and extracellular (ECW) water compartments in a group of 21 prepubertal young obese children of both sexes in comparison with a group of 18 normal children weight matched for age. Our data indicate that obesity is associated with a highly significant relative expansion of extracellular water (ECW/ICW = 0.61 +/- 0.19 and 0.76 +/- 0.09 in control and obese subjects, respectively; P < 0.0015). This observation, which has been already reported in adult women, suggests that some disturbances of water homeostasis have an early onset and stress the need for an early control of energy imbalance in children. These findings are of great concern also in the field of human body composition, suggesting the opportunity for a critical reevaluation of the assumed constancy of some human body characteristics. Body composition methodologies developed for "normal" populations would require adjustment for use in the obese population, since a considerable error would be introduced.

Body Water↗