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Biomedical subjects

G Chiumello

Publications and source records attributed to G Chiumello.

At least 19 recordsLinked to original sources
PubMed2001

Diagnosis of hypochondroplasia: the role of radiological interpretation. Italian Study Group for Hypochondroplasia.

BACKGROUND: Hypochondroplasia is characterised by phenotypic and genetic heterogeneity. Differentiation from other conditions with disproportionate short stature is often difficult. OBJECTIVE: To determine the reliability of radiological interpretation in the diagnosis of hypochondroplasia and to evaluate the most typical skeletal abnormalities. These data were correlated with molecular findings. MATERIALS AND METHODS: We enrolled 21 patients with suspected hypochondroplasia based on the radiological criteria most often reported in the literature on this disease. Height, sitting height and head circumference were measured in all patients. Radiographs of the lumbar spine, left leg, pelvis and left hand were obtained. The presence of the N540K mutation in the fibroblast growth factor receptor 3 (FGFR3) gene was verified by restriction enzyme digestion. All radiographs which enabled the selection of patients were reviewed a second time by two paediatric radiologists in a blinded examination. Their results were compared. RESULTS: Both radiologists confirmed the diagnosis in 10 out of 21 patients, while in the other 52% of cases they excluded the disease, were uncertain or they did not agree on the final interpretation of the data. The best agreement rate was obtained in the evaluation of the lumbar spine and the legs. The radiological features of the nine patients (43%) carrying the N540K substitution were not remarkably different from the ones reported in the patients without this mutation. CONCLUSION: Our study shows that the crucial skeletal regions on which to focus the diagnosis of hypochondroplasia are the lumbar spine and legs, while the pelvis and hands seem to be less characteristic. To reduce the risk of misdiagnosis, accurate radiological and clinical evaluation is needed, especially in cases without a defined genetic defect.

Achondroplasia↗
PubMed2001

Hyperplastic pituitary gland, high serum glycoprotein hormone alpha-subunit, and variable circulating thyrotropin (TSH) levels as hallmark of central hypothyroidism due to mutations of the TSH beta gene.

Inheritable isolated central hypothyroidism (ICH) due to mutations of TSH beta gene has been reported in few patients. For this reason the diagnostic criteria are vague. The disorder is usually characterized by undetectable TSH levels, although low/normal serum TSH, depending on TSH measurement methods, has been documented in some patients. Here we report an Egyptian girl with ICH due to a novel nonsense mutation of the TSH beta gene (Q49X). She was referred at 75 days of age for severe clinical signs of hypothyroidism, whose central origin was documented by normal serum TSH, low free T(4) and free T(3) levels, impaired TSH response to TRH, absence of (99)Tc thyroidal uptake, and antithyroid autoantibodies. Ultrasound revealed a hypoplastic thyroid, whereas magnetic resonance imaging showed a hyperplastic pituitary. All other pituitary hormones, including PRL, were normally secreted. A diagnosis of idiopathic ICH was made, and substitutive L-T(4) treatment was started at 81 days of age. At the age of 7 yr the patient had normal thyroid hormone levels, but was severely mentally retarded. Interestingly, the sella computed tomography scan had completely normalized. At 8 yr of age the patient was reinvestigated after 6-week L-T(4) withdrawal. TSH values were highly variable depending on the measurement method used, whereas extremely high levels of circulating free glycoprotein alpha-subunit were recorded. Despite the fact that mutant TSH beta lacks 60% of the C-terminal amino acid sequence, it forms with the alpha-subunit a heterodimer with preserved immunoreactivity in some TSH measurement methods, but the mutant heterodimer is completely devoid of bioactivity. In conclusion, high circulating free glycoprotein alpha-subunit levels, variable TSH levels, and, possibly, hyperplastic pituitary gland are the hallmark of ICH due to mutations of the TSH beta gene.

Base Sequence↗
PubMed2001

Macroamylasemia attributable to gluten-related amylase autoantibodies: a case report.

BACKGROUND: Macroamylasemia (MA) is a benign condition caused by circulating macroamylase complexes of pancreatic or salivary amylase bound to plasma proteins, which cannot be cleared by the renal glomeruli. In most cases, the macromolecular amylase represents a complex of normal amylase and either immunoglobulin A or G and may be a specific antigen-antibody complex. Celiac disease (CD) is a permanent intolerance to ingested gluten that results in immunologically mediated inflammatory damage of the small intestinal mucosa. Several recent population-based serologic surveys have shown CD to be a common disorder, possibly affecting 1 in 200 to 250 individuals in most countries studied, including the United States, where overt CD is rare, indicating a high proportion of subclinical disease. The diagnosis of CD currently rests on the histological demonstration of the characteristic lesion in the small intestine and the subsequent clinical response to the introduction of a gluten-free diet. MA associated with CD has been described in adult patients, and in a few cases, MA decreased or resolved after a strict gluten-free diet. A few single cases of MA have been described in childhood, but no association with CD has been reported so far. We report a girl with CD, autoimmune thyroiditis, and MA, in whom CD-related antibodies to amylase and to exocrine pancreas tissue resolved with a gluten-free diet. CASE REPORT: An 11-year-old girl was referred for chronic abdominal pain and growth retardation associated with persistent hyperamylasemia and suspected chronic pancreatitis. We confirmed elevated serum amylase, normal serum lipase, and very low 24-hour urine amylase and amylase clearance/creatinine clearance ratio, consistent with MA. Serologic tests for CD were positive, and the diagnosis was confirmed by small bowel biopsy showing subtotal villous atrophy. Thyroid function tests showed a pronounced hypothyroidism, associated with high titers of thyroid microsomal and thyroglobulin antibodies. Screening for other autoantibodies-including antinuclear, islet cell, glutamic acid decarboxylase, protein tyrosine phosphatase islet antigen 512, adrenal gland, and cytoplasmic neutrophil granulocyte antibodies-was negative. A diagnosis of CD, MA, and hypothyroidism attributable to autoimmune thyroiditis was made. A gluten-free diet and oral replacement with L-thyroxine was started with clinical improvement. Serum amylase and amylase clearance/creatinine clearance ratio normalized, consistent with resolution of MA. STUDY DESIGN AND METHODS: The patient's serum samples were obtained at the time of CD diagnosis and at 3 and 12 months after instituting a gluten-free diet. Serum samples from 10 consecutive untreated celiac children were disease controls, and 39 participants with no gastrointestinal symptoms and no family history of CD served as healthy controls. The origin of MA as determined by complexes of amylase with circulating immunoglobulins was tested by the measurement of amylase on supernatants after precipitation of immune complexes with either protein A Sepharose or polyethylene glycol. The precipitation of >60% of amylase activity was consistent with the presence of MA. Immunoglobulin G (IgG) and immunoglobulin A (IgA) circulating autoantibodies to amylase were measured using recently developed enzyme-linked immunosorbent assay (ELISA), using porcine amylase as antigen. Results were expressed as arbitrary units (AUs). Statistical analysis was performed by Student's t test for unpaired data. IgA and IgG antibodies to exocrine pancreas tissue were detected by indirect immunofluorescence on human pancreas cryosections. RESULTS: Serum immunoprecipitation with either protein A Sepharose or polyethylene glycol reduced amylase activity from 1698 to 89 U/L (94.8%) and to 75 U/L (95.6%), with only marginal reduction in control serum samples. The ELISA for autoantibodies to amylase detected high values, both IgA (3531 AU) and IgG (1855 AU), in the serum sample from the patient at CD diagnosis. IgA autoantibodies (mean +/- standard deviation) were 3.4 +/- 2.5 AU in healthy controls, and 2.1 +/- 1.2 AU in celiac controls; IgG autoantibodies were 10 +/- 4.8 AU in healthy controls and 8.5 +/- 3.2 AU, respectively. Autoantibodies to exocrine pancreas tissue were documented in patient sera at the time of CD diagnosis, both IgA and IgG, but not in control groups. Preincubation of patient's serum with excess of alpha-amylase specifically inhibited antibody binding to coated amylase in the ELISA, and partially inhibited immunoreactivity to exocrine pancreas. Autoantibodies to alpha-amylase and to exocrine pancreas declined in CD patients after institution of a gluten-free diet. CONCLUSIONS: Few cases of MA have been described in children, and in all amylase determination was part of the clinical investigation for abdominal pain or trauma. (ABSTRACT TRUNCATED)

Amylases↗
PubMed2000

Cognitive function and neurophysiological evaluation in early-treated hypothyroid children.

In this study, we assessed cognitive function and neurophysiological development in congenitally hypothyroid (CH) children. We performed a cross-sectional study at the outpatient Pediatric Clinic and Department of Neurophysiology at San Raffaele Hospital, Milan. The study enrolled 25 CH patients (6.00-10.83 years of age) detected by neonatal screening, and 34 healthy control children (4-11 years of age). Patients and controls had comparable scores at neuropsychological tests (WISC-R), and at auditory P300 tests. In contrast, we found significantly longer LLSEP latencies in CH patients (p < 0.03). CH patients treated 30 days after birth showed lower scores at neuropsychological tests, but not at neurophysiological tests, compared to patients who started the replacement therapy earlier. Patients with more severe fetal hypothyroidism (T4 levels at diagnosis < or = 2 micrograms/dl) had lower neuropsychological scores, and similar neurophysiological results, compared with patients with moderate fetal hypothyroidism. The severity of fetal hypothyroidism and early treatment influence the mental outcome of CH patients. Neurophysiological results show that central nervous system damage occurs in some patients despite early treatment.

Child↗
PubMed2000

Vasopressin and thirst in patients with posterior pituitary ectopia and hypopituitarism.

OBJECTIVE: Partial diabetes insipidus has been documented in patients with congenital hypopituitarism and posterior pituitary ectopia, some cases being clinically silent except for enuresis. The objective of our study was to evaluate vasopressin (AVP) secretion and thirst appreciation in hypopituitary patients with posterior pituitary ectopia. PATIENTS: Twelve males and three females, aged between 13 and 38 years (median 19 years). Eleven had multiple pituitary deficiencies, adequately replaced at the time of the study, and four were only growth hormone deficient. None of the patients suffered from polyuria, polydipsia or nocturnal enuresis. We tested the patients with a 5% NaCl infusion. Five patients with abnormal vasopressin production were also tested with nitroprusside, which affects baroceptor vasopressin secretion. RESULTS: We found that only two out of 12 patients had normal AVP secretion. Thirst assessment showed severe hypodipsia in one patient, hyperdipsia in three out of 15 and more subtle abnormalities in two out of 15 patients. Concordance was found between osmotically and baroceptor-stimulated vasopressin. CONCLUSIONS: Patients with posterior pituitary ectopia showed a high prevalence of subclinical subnormal vasopressin response to the osmolar stimulus and moreover an impairment of thirst appreciation. Our data on nonosmotically stimulated AVP release suggest the existence of a damage in the hypothalamic vasopressin secreting centres.

Adolescent↗
PubMed2000

Dual-energy X-ray absorptiometry: analysis of pediatric fat estimate errors due to tissue hydration effects.

Dual-energy X-ray absorptiometry (DXA) percent (%) fat estimates may be inaccurate in young children, who typically have high tissue hydration levels. This study was designed to provide a comprehensive analysis of pediatric tissue hydration effects on DXA %fat estimates. Phase 1 was experimental and included three in vitro studies to establish the physical basis of DXA %fat-estimation models. Phase 2 extended phase 1 models and consisted of theoretical calculations to estimate the %fat errors emanating from previously reported pediatric hydration effects. Phase 1 experiments supported the two-compartment DXA soft tissue model and established that pixel ratio of low to high energy (R values) are a predictable function of tissue elemental content. In phase 2, modeling of reference body composition values from birth to age 120 mo revealed that %fat errors will arise if a "constant" adult lean soft tissue R value is applied to the pediatric population; the maximum %fat error, approximately 0.8%, would be present at birth. High tissue hydration, as observed in infants and young children, leads to errors in DXA %fat estimates. The magnitude of these errors based on theoretical calculations is small and may not be of clinical or research significance.

Absorptiometry, Photon↗
PubMed2000

Growth and insulin-like growth factors (IGFs) in children with insulin-dependent diabetes mellitus at the onset of disease: evidence for normal growth, age dependency of the IGF system alterations, and presence of a small (approximately 18-kilodalton) IGF-binding protein-3 fragment in serum.

Data on growth of children with insulin-dependent diabetes mellitus (IDDM) before the onset of disease are conflicting, and although the insulin-like growth factor (IGF) system has almost invariably been found altered at diagnosis, most of previous studies are affected by the small number of patients investigated. We studied 60 IDDM children at the onset of disease, comparing their stature with target height, normal growth standards, and height of 102 sex- and age-matched controls. Furthermore, we assessed serum IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) levels and IGFBP-3 circulating forms. IDDM children were subdivided into 2 groups according to an age above (n = 26) or below (n = 34) 6 yr. The values of endocrine variables of diabetics older than 6 yr were compared with those of 34 age-matched controls. Although the height of diabetics was higher than growth reference values (mean height +/- SD, 0.64+/-1.4 z-score) and their target height (mean target height +/- SD, 0.1+/-0.84 z-score; P < 0.005), no significant difference in height was found between IDDM children and controls (mean height +/- SD, 0.64+/-0.95 z-score) even analyzing the 2 age groups separately. Overall, IDDM children showed reduced levels of IGF-I (mean +/- SD, -0.65+/-1.9 z-score) and normal levels of IGF-II (mean +/- SD, -0.05+/-1.2 z-score) and IGFBP-3 (mean +/- SD, -0.06+/-1.2 z-score). However, whereas patients younger than 6 yr showed normal values of IGF-I, IGF-II, and IGFBP-3, these peptides were significantly reduced in older subjects compared with either younger IDDM children or controls (P < 0.01). IGFBP-3 immunoblot analysis revealed the presence of an approximately 18-kDa fragment of IGFBP-3 in addition to the major approximately 29-kDa fragment and the intact form (approximately 42-39 kDa) in 46 of 60 IDDM patients, whereas the approximately 18-kDa band was absent in all 34 control sera. No relationship was found between the endocrine variables and stature at diagnosis. In conclusion, our results indicate that IDDM children at the onset of disease are not taller than healthy peers and have increased IGFBP-3 proteolytic activity. Finally, although the IGF system is normal in younger IDDM children, older patients have reduced IGF levels.

Age of Onset↗
PubMed2000

Precocious puberty and body composition: effects of GnRH analog treatment.

INTRODUCTION: Body composition changes with age and sex differences become significant only after puberty. Boys and girls before the age of 8 yr do not differ in fat, lean or bone mineral mass. Hormonal influences during pubertal development determine the physiological adult male and female body composition phenotype. AIM: The aim of our study was to evaluate body composition changes due to central precocious puberty (PP) and the specific effects of therapy on these modifications. SUBJECTS AND METHODS: Sixteen patients (14 girls, 2 boys) were included in the study. They were diagnosed as affected by idiopathic PP according to standard hormonal and clinical criteria; anatomic alterations of hypothalamus-hypophysis region were excluded by MRI. Mean age at diagnosis was 5.9 +/- 1.9 yr. All patients received GnRH analog (Leuprolide or Triptorelin) treatment subcutaneously every 4 weeks for at least 1 yr. Mean period of treatment was 3.4 +/- 1.9 yr. Standard anthropometry and body composition analysis were performed at baseline and every 6-12 months. A group of healthy subjects with normal timing of puberty was matched (for age or for pubertal stage) served as the control group (CA or CP, respectively). RESULTS: Patients with PP showed at baseline a significant increase of BMI and relative body weight; lean and fat compartments were also increased but not significantly. During treatment, the PP group showed increased fat mass compared to CA (p<0.05), while no difference was found between PP and CP. Lean mass was similar to CA but lower than in CP (p<0.05). During treatment a significant increase in lean mass (both as total as well as limb mass) was observed. After stopping treatment there was no difference between PP and CP, except for lower lean mass (p<0.04). CONCLUSION: When puberty occurs precociously, lean and fat mass are not significantly different from age-matched control subjects. Data collected during treatment confirm a shortening of prepubertal lean mass development and the block of further lean mass development due to puberty itself, while fat mass accumulation continues. The net result of these modifications determines a typical body composition pattern in PP patients, after the end of therapy: lean mass is reduced by a shortening of the prepubertal growing period and by the "menopausal effect" of treatment itself. Fat mass is increased as a consequence of therapy and could lead to future obesity.

Adipose Tissue↗
PubMed1999

Comparison of tissue transglutaminase-specific antibody assays with established antibody measurements for coeliac disease.

Tissue transglutaminase C has recently been identified as one of the auto-antigens of endomysial antibodies found in coeliac disease. In this study we have cloned the human autoantigen and developed immunoassays measuring antibodies to transglutaminase in order to compare their diagnostic performance to that of established markers of the disease. A radiobinding assay using in vitro transcribed and translated 35S-methionine-labelled transglutaminase detected IgG antibodies in 110 and IgA antibodies in 109 of 112 patients at diagnosis of coeliac disease and in three and four of 92 control subjects, respectively. A radiobinding assay measuring both IgG and IgA transglutaminase antibodies identified 111 (99.1%) of the patients and 4 (4.3%) control subjects. Concordance of this assay with the IgA endomysial antibody test was found in 108 patients and 89 control subjects: two patients who had IgA deficiency and a third patient without IgA deficiency were only detected in the radiobinding assay; one patient had weak IgA endomysial antibodies only, and three of the control subjects with weak transglutaminase antibodies by radiobinding assay were undetectable in the IgA endomysial antibody assay. IgA and IgG ELISA using guinea pig transglutaminase and commercial ELISA measuring anti-gliadin antibodies had lower sensitivity and specificity than the radiobinding assays or the IgA endomysial antibody assay. This study confirms tissue transglutaminase C as a major autoantigen in coeliac disease and describes novel radiobinding assays for large scale testing to identify cases of coeliac disease.

Adolescent↗
PubMed1999

Antibodies to tissue transglutaminase C in type I diabetes.

AIMS/HYPOTHESIS: Silent coeliac disease is a gluten driven autoimmune disease which is relatively frequent in patients with Type I (insulin-dependent) diabetes mellitus. To determine the extent of gluten associated autoimmunity in Type I diabetes, autoantibodies to tissue transglutaminase C, a major autoantigen in coeliac disease, were measured in patients with new-onset Type I diabetes. METHODS: We measured IgG and IgA tissue transglutaminase C autoantibodies using human recombinant antigen and radio-binding assays in a cohort of 287 patients with new-onset Type I diabetes, 119 with Type II (non-insulin-dependent) diabetes mellitus and in 213 control subjects. RESULTS: We found IgA and IgG tissue transglutaminase C antibodies in 24 (8 %) patients with Type I diabetes; 97 (33 %) patients had IgG antibodies only and 1 IgA antibodies only. Antibody concentrations were highest in those with both IgA and IgG antibodies. Only 2 (2 %) patients with Type II diabetes and 2 (1 %) control subjects had either IgG or IgA tissue transglutaminase C antibodies. Patients with HLA DRB1(*)04 alleles had the highest prevalence of IgG tissue transglutaminase C antibodies. CONCLUSION/INTERPRETATION: These data show that almost 10 % of patients have autoimmunity typical of coeliac disease and that another 30 % have low level tissue transglutaminase C antibody binding. This high prevalence suggests either involvement of the gut in the pathogenesis of Type I diabetes or that transglutaminase is a secondary autoantigen resulting from beta-cell destruction. [Diabetologia (1999) 42: 1195-1198]

Adolescent↗
PubMed1999

Persisting obesity starting before puberty is associated with stable intraabdominal fat during adolescence.

OBJECTIVES: To observe the evolution of intraabdominal adipose tissue (IAT) in obese prepubertal children, who did not change their degree of obesity during adolescence and to evaluate its relationship with metabolic risk indexes (RI). DESIGN: Longitudinal study of 16 obese adolescents (eight male and eight female) in whom relative body weight (RBW) did not change significantly and pubertal development was completed during the study period. MEASUREMENTS: Magnetic resonance imaging (MRI) scan at lumbar level (L4) three times during a 4 y period. At basal and at four years biochemical assays for metabolic indexes. RESULTS: IAT did not differ significantly over the three measurement times and showed significant correlations between first and second (r = 0.66, P < 0.005), first and third (r = 0.61, P < 0.01) and second and third values (r = 0.84, P < 0.0001). Subcutaneous adipose tissue (SAT) increased significantly from basal to third evaluation (P < 0.002). At baseline, IAT correlated significantly with lipids (total and LDL cholesterol r = 0.72, P < 0.004), while at the end of the study, IAT correlated positively with insulin (fasting insulin r = 0.55, P < 0.008, insulin area after oral glucose tolerance test (OGTT) r = 0.60, P < 0.03, fasting insulin/glucose r = 0.67 P < 0.006) and negatively with high density lipoprotein (HDL) cholesterol (r = -0.55, P < 0.04). CONCLUSIONS: Obesity achieved before puberty, and stable during adolescence, showed a relatively stable amount of IAT. In post pubertal children the relationship of IAT to clinically significant risk factors resemble the pattern in obese adults.

Abdomen↗
PubMed1999

Bone density and bone metabolism are normal after long-term gluten-free diet in young celiac patients.

OBJECTIVES: Osteoporosis and alterations of bone metabolism are frequent complications of celiac disease. We evaluated the impact of long-term gluten-free diet (GFD) initiated during childhood and adolescence on bone mineralization and bone metabolism. METHODS: We studied 30 celiac patients on GFD for > or = 5 yr. The mean age at diagnosis was 11.4+/-5.0 yr, and the mean duration of GFD was 10.7+/-4.3 yr. Results were compared with those obtained in 240 healthy controls. Bone mineral density (BMD) was measured in the lumbar spine and in the whole skeleton by dual-energy x-ray absorptiometry. Serum levels of bone-specific alkaline phosphatase (BALP) and N-terminal propeptide of type I procollagen (PINP) were measured as bone formation indices, and urine levels of N-telopeptide of type I collagen (NTx) as bone resorption index. RESULTS: BMD measurements of celiac patients (lumbar spine: 1.131+/-0.121 g/cm2; total body: 1.145+/-0.184 g/cm2) did not differ from those of control subjects (lumbar spine: 1.131+/-0.184 g/cm2; total body: 1.159+/-0.118 g/cm2). The levels of BALP, PINP, and NTx of celiac patients did not differ from those of controls. Patients who started GFD before puberty had BMD and bone metabolism measurements comparable to those of patients who started GFD during puberty. CONCLUSIONS: Our data show that long-term dietary treatment ensures normal mineralization and bone turnover.

Absorptiometry, Photon↗
PubMed1999

Longitudinal changes of bone density and bone resorption in hyperthyroid girls during treatment.

Low bone mineral density (BMD) and increased bone turnover are common features of untreated hyperthyroidism in adult patients. The effect of treatment on BMD is still controversial. BMD and bone metabolism in hyperthyroid children have not been thoroughly investigated. In the present study, we measured spinal and whole body BMD by dual-energy X-ray absorptiometry in a group of 13 girls (aged 5.0-14.9 years) at diagnosis of hyperthyroidism. The bone resorption rate was assessed by urine measurement of N-terminal telopeptide of type I collagen (NTX). Hyperthyroid patients have been studied longitudinally during treatment. BMD values and NTX urine concentrations have been also determined in 155 healthy Caucasian girls (aged 2.4-24.2 years). Spinal and whole body bone density measurements were significantly lower compared with healthy controls in untreated hyperthyroid girls, after correction for differences in age and anthropometric measurements (p </= 0.033). Bone density measurements obtained after 12 and 24 months of treatment were no longer different from those of healthy girls. NTX urine levels at diagnosis of thyrotoxicosis were significantly higher than those found in healthy controls (p < 0.0001); 6 months after treatment, the urine levels did not show significant differences, and they remained stable after 12 and 24 months of therapy. Inverse correlations at diagnosis were found between serum-free thyroxine (FT4) serum levels and spinal (r = -0.42) and whole body bone density (r = -0.41); FT4 and free triiodothyronine serum levels directly correlated with the NTX concentration (r = 0. 77, and r = 0.71, respectively). In conclusion, the results of the present study demonstrate that low bone density values and high bone resorption rates are found in hyperthyroid children and adolescents at diagnosis of the disease. Our data also demonstrate that antithyroid treatment is able to reduce dramatically the bone resorption and to increase significantly both spinal and total body BMD, granting physiologic conditions for the achievement of the best obtainable peak bone mass.

Adolescent↗