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Biomedical subjects

F De Luca

Publications and source records attributed to F De Luca.

At least 19 recordsLinked to original sources
PubMed2002

Three-year prospective evaluation of glucose tolerance, beta-cell function and peripheral insulin sensitivity in non-diabetic patients with thalassemia major.

The aim of this prospective study was to evaluate the evolution of glucose tolerance (GT), insulin secretion and peripheral insulin sensitivity during a 3-yr follow-up in a homogenous population consisting of fourteen non-diabetic adults with thalassemia major (TM). All the patients underwent 2 OGTTs with a 3-yr interval and random measurements of fasting glycemia during the entire follow-up. At the time of both OGTTs, peripheral insulin sensitivity was assessed by both homeostatic model assessment (HOMA) index and a novel index derived from the OGTT. At the second OGTT patients exhibited both significantly higher fasting glucose concentrations and enhanced glycemic responses, with greater average glucose areas. GT deterioration over time was accompanied by a reduction of insulin sensitivity, with no concomitant change of insulin secretion. No patient developed diabetes mellitus (DM) during follow-up. To conclude, the natural history of glycometabolic status in TM adults seems to be characterized by a GT deterioration over time, which may probably reflect an increase of insulin resistance. GT deterioration is more evident in patients with the highest responses to the 1st OGTT and particularly in those with pre-existing impaired GT.

Adult↗
PubMed2002

Italian cross-sectional growth charts for height, weight and BMI (6-20 y).

OBJECTIVE: To trace growth charts for height, weight and body mass index (BMI) that apply to the whole Italian population. Different charts were drawn for central-north and south Italy since children in central-north regions are known to be taller and leaner. DESIGN: Cross-sectional study. SETTING: A sample of schoolchildren covering 16 of the 20 Italian regions, with data collected between 1994 and 2000. SUBJECTS: A total of 27 421 girls and 27 374 boys, aged 6-20 y. METHODS: Height and weight were measured using portable Harpenden stadiometers and properly calibrated scales, respectively. SIEDP references are presented both as centiles and as LMS curves for the calculation of standard deviation scores. According to International Obesity Task Force, SIEDP charts for BMI include the limits for overweight and obesity, ie the centiles having, at 18 y of age, the value of 25 and 30 kg/m(2), respectively. RESULTS: The comparison between SIEDP and Tanner et al's charts for height, still in use among most Italian paediatricians, shows that before puberty Italian children are 2-4 cm taller than their English peers. Because of these differences, Tanner's charts fail to detect, when applied to Italian children, 50-90% of short children aged 6-11 y, ie with stature below the 3rd centile of their reference population. Rolland-Cachera et al's centiles for BMI are lower than those of SIEDP standards, mainly during adolescence (up to 6.6 kg/m(2) for the 97th centile), and apply poorly to Italian children. The prevalence of overweight is 27 (boys) and 19% (girls) in south Italy vs 17 (boys) and 10% (girls) in central-north Italy. CONCLUSIONS: These references intend to supply Italian paediatricians with a tool that avoids the use of outdated or inadequate charts, and thus should be suitable for monitoring their patients' growth. SPONSORSHIP: Italian Society for Pediatric Endocrinology and Diabetes (SIEDP).

Adolescent↗
PubMed2002

TSH secretory pattern and thyroid function in children with growth hormone neurosecretory dysfunction.

We evaluated the TSH secretory pattern and free T4 in 10 prepubertal children with short stature, normal response to GH provocative tests, and reduced GH integrated concentration (IC-GH) (GH neurosecretory dysfunction). Although their nadir TSH, peak TSH, TSH surge, and free T4 were lower than those of 12 children with short stature and normal IC-GH, none of the differences reached statistical significance. Thus, our results suggest that children with low IC-GH (GH neurosecretory dysfunction) exhibit a TSH secretory pattern and thyroid function similar to those with normal IC-GH.

Bone Development↗
PubMed2001

Hydrodynamic radii and lipid transfer in prostasome self-fusion.

The characteristics of human prostasomal vesicles have been investigated by three methods, namely, dynamic light scattering, transfer of a lipophylic fluorescent dye (R18), and electron microscope appearance. The vesicle preparations were stable for a long time and their diameters were in the range of 200 nm. The exposure to acidic pH values (about 5) increased both particle radii and the transfer of R18. The microscopic appearance was also affected by the pH value. We infer that these changes are due to a self-fusion of prostasome vesicles; this fusion is protein-dependent since various methods used by us and able to affect the protein component of membranes (boiling, extraction of lipid and liposome preparation, treatment with pronase) all abolished the effect seen at pH 5 on intact particles.

Acids↗
PubMed2001

Identification of novel WFS1 mutations in Italian children with Wolfram syndrome.

Six unrelated Italian children with Wolfram syndrome (WS) were analyzed for mutations in the WFS1. Four novel mutations (1387delCTCT, S443I, 1519del16, and IVS6+16g->a) were identified. In addition, we found two new, probably neutral changes (A684V and R708C). Other previously described variants were a heterozygous I333V in three alleles and the H611R in two. The 1519del16 mutation was carried by two patients whereas the CTCT deletion occurred in three subjects from two apparently unrelated families with WS. The current study expands the spectrum of mutations in WFS1 and represents the first molecular characterization of Italian WS patients.

Adolescent↗
PubMed2001

Effects of higher rank multipoles on relaxation of an I = 3 spin system.

Magnetic multipoles of rank higher than one become active in spin systems with I > 1/2 and their contribution to relaxation depends on dynamics. The appearance of multipole terms complicates the relaxation description and supports the multiexponential behavior of relaxation. In this paper the effects of high-rank multipoles on lineshape and longitudinal relaxation of I = 3 spin systems are presented. Results obtained from both numerical simulation and experimental data show that longitudinal and transverse relaxation are strongly influenced by these multipole terms, especially at lower temperature where, due to lower molecular mobility, the extreme narrowing condition is not fulfilled.

Journal Article↗
PubMed2001

Proton MRI of (13)C distribution by J and chemical shift editing.

The sensitivity of (13)C NMR imaging can be considerably favored by detecting the (1)H nuclei bound to (13)C nuclei via scalar J-interaction (X-filter). However, the J-editing approaches have difficulty in discriminating between compounds with similar J-constant as, for example, different glucose metabolites. In such cases, it is almost impossible to get J-edited images of a single-compound distribution, since the various molecules are distinguishable only via their chemical shift. In a recent application of J-editing to high-resolution spectroscopy, it has been shown that a more efficient chemical selectivity could be obtained by utilizing the larger chemical shift range of (13)C. This has been made by introducing frequency-selective (13)C pulses that allow a great capability of indirect chemical separation. Here a double-resonance imaging approach is proposed, based on both J-editing and (13)C chemical shift editing, which achieves a powerful chemical selectivity and is able to produce full maps of specific chemical compounds. Results are presented on a multicompartments sample containing solutions of glucose and lactic and glutamic acid in water.

Journal Article↗
PubMed2001

Differentiation among three species of bovine Thelazia (Nematoda: Thelaziidae) by polymerase chain reaction-restriction fragment length polymorphism of the first internal transcribed spacer ITS-1 (rDNA).

Thelazia gulosa, Thelazia rhodesi and Thelazia skrjabini are nematodes transmitted by some species of Musca (Diptera: Muscidae) which cause ocular infestations in bovines. Differences in the rDNA of these species were determined by a PCR using different sets of relatively conserved oligonucleotide primers. PCR on the first internal transcribed spacer (ITS-1) revealed differences in size in Thelazia species (437 bp for T. gulosa, 370 bp for T. rhodesi and 506 bp for T. skrjabini) while the DNA control of Musca spp. was not amplified. The ITS-1 amplicons of the three species were sequenced and then analysed. The GC contents ranged from 26 to 36% and the level of differences in the nucleotide sequences of ITS-1 was lower between T. skrjabini and T. gulosa (39%) than the latter and T. rhodesi (49-56%). Restriction fragment length polymorphism (RFLP) of ITS-1 amplicons was also carried out and the restriction profiles compared. Clear genetic differences among the three Thelazia examined were demonstrated by using the enzymes HpaII, CpoI and SspI. This PCR-RFLP for the delineation of T. gulosa, T. rhodesi and T. skrjabini offers prospects as a molecular epidemiological tool to study parasite transmission patterns and prevalence.

Amino Acid Sequence↗
PubMed2001

In vivo detection of 13C-enriched glucose metabolites in mouse brain by T-SEDOR imaging.

Protons J-coupled to 13C were selectively detected in the mouse head by in vivo 1H NMR imaging based on Twin Spin Echo DOuble Resonance (T-SEDOR) excitation. This pulse sequence combines a good chemical specificity with high sensitivity, requires no solvent pre-saturation and is well adapted to the imaging modality. 1H T-SEDOR maps of the mouse head allowed detection of areas of preferential accumulation of 13C-enriched compounds, upon repeated injections of uniformly 13C-labelled glucose, which induced hyperglycemia. The results demonstrated the feasibility, both in time scale and metabolite concentration, of applying T-SEDOR MRI for in vivo mapping brain areas characterized by enhanced rates of glucose uptake and/or accumulation of its metabolites.

Animals↗
PubMed2001

Prevention of new sensitizations in asthmatic children monosensitized to house dust mite by specific immunotherapy. A six-year follow-up study.

BACKGROUND: Specific immunotherapy (SIT) is a recognized way of treating IgE-mediated respiratory diseases. The clinical outcome is usually better in allergic children than in adults. OBJECTIVE: To increase our knowledge of the ability of SIT to prevent the onset of new sensitizations in monosensitized subjects, so far poorly documented. METHODS: 134 children (age range 5-8 years), who had intermittent asthma with or without rhinitis, with single sensitization to mite allergen (skin prick test and serum-specific IgE), were enrolled. SIT was proposed to all the children's parents, but was accepted by only 75 of them (SIT Group). The remaining 63 children were treated with medication only, and were considered the Control Group. Injective SIT with mite mix was administered to the SIT Group during the first three years and all patients were followed for a total of 6 years. All patients were checked for allergic sensitization(s) by skin prick test and serum-specific IgE every year until the end of the follow-up period. RESULTS: Both groups were comparable in terms of age, sex and disease characteristics. 123 children completed the follow-up study. At the end of the study, 52 out of 69 children (75.4%) in the SIT Group showed no new sensitization, compared to 18 out of 54 children (33.3%) in the Control Group (P < 0.0002). Parietaria, Gramineae and Olea were the most common allergens responsible for the new sensitization(s). CONCLUSIONS: According to our data, SIT may prevent the onset of new sensitizations in children with respiratory symptoms monosensitized to house dust mite (HDM).

Air Pollution, Indoor↗
PubMed2001

Management of puberty in constitutional delay of growth and puberty.

Constitutional delay of growth and puberty (CDGP) is the most common presenting form of short stature, but no single test can infallibly discriminate CDGP and isolated hypogonadotrophic hypogonadism. Management of puberty in CDGP aims to optimise not only growth maintaining body proportions and improving peak bone mass without impairing growth potential--but also well-being; for example, the distress boys often suffer because of their lack of growth and pubertal progression can affect their school performance and social relationships. Typical sex steroid treatments to induce puberty in boys with CDGP include testosterone (T) enanthate, T undecanoate, mixed T esters, T transdermal patches, and oxandrolone p.o. Compared with other regimens, short-course low-dose depot T i.m. is an effective, practical, safe, well tolerated, and inexpensive regimen. Some unresolved problems in management include optimal timing and dose of sex steroid treatment, the role of GH in CDGP, and the management of CDGP in girls.

Adolescent↗
PubMed2001

Multiple pituitary hormone deficiency: management of puberty for optimal auxological results.

The overview in this paper focuses on ways of achieving optimal auxological results in puberty, principally in idiopathic and congenital multiple pituitary hormone deficiency (MPHD), suggested by the co-authors. We agreed that diagnosing gonadotrophin insufficiency/deficiency is difficult in young children and should be repeated in late prepuberty, but a firm diagnosis of MPHD helps avoid endocrine re-testing at the end of growth. The hypothalamic-pituitary axis must be reassessed periodically in evolving endocrinopathies, though current practice varies widely. Optimum age to induce puberty is 11-12 years in girls and 13-14 boys, and sex steroids are the preferred agents. Short-course testosterone to increase micropenis size is advantageous, but inducing early testicular maturation is not known to improve later fertility. There is also little evidence for increasing the dose of GH during puberty, though therapy should continue to final height, and possibly until peak bone mass is achieved. Delaying puberty is an option in septo-optic dysplasia, and minimising the dose of hydrocortisone is crucial in treating ACTH/cortisol insufficiency. Many unresolved questions remain in this difficult area.

Adolescent↗
PubMed2001

Aldosterone synthase deficiency type I with no documented homozygous mutations in the CYP11B2 gene.

This case report concerns a girl born from non-consanguineous parents and hospitalized in another hospital at the age of 14 days because of a severe salt-losing syndrome (Na=125, K=8.6 mEq/l). In spite of normal genitalia, diagnosis of 21-hydroxylase deficiency was assessed on the basis of a slightly increased 17-OH-progesterone serum level (6.4 ng/ml). The onset of both hydrocortisone and 9alpha-fluorohydrocortisone therapy was followed by a resolution of the clinical picture. At the age of 60 days she was admitted to our clinic for a re-evaluation of the diagnosis. Steroid hormone serum levels were measured after withdrawal of therapy and diagnosis of corticosterone methyl oxidase (CMO) deficiency type I was definitely established in the light of the biochemical results: i.e. very low 18-hydroxycorticosterone (18-OH-B) serum levels (20 pg/ml), an abnormally high corticosterone/18-OH-B serum ratio (306.5) and an abnormally low 18-OH-B/aldosterone serum ratio (2.1). This autosomal recessively inherited disorder can be differentiated from CMO type II and other salt-wasting syndromes only on the basis of the serum steroid hormone pattern. After establishing the diagnosis of CMO I deficiency, hydrocortisone therapy was withdrawn whilst treatment with 9alpha-fluorohydrocortisone was begun again, with a satisfactory clinical and metabolic impact. Direct sequences of the patient's DNA were able to identify only a (heterozygous) amino acid substitution in exon 7 of that gene, which is known to have only a small effect on enzyme activity and cannot be the only cause of the patient's phenotype: valine-386-alanine (V386A) GTG-->GcG. No homozygous mutations in the CYP11B2 gene were observed. This is the first report of a patient with CMO type I who does not carry any homozygous mutation in the entire CYP11B2 alleles, whereas some cases with no mutations in this gene have already been reported in CMO II. The present study seems to be inconsistent with the previously reported correlation of the phenotype and genotype in CMO type I. A reasonable question that might be raised on the basis of our findings in this case report is whether other genes, apart from CYP11B2, are involved in the regulation of terminal aldosterone synthesis.

17-alpha-Hydroxyprogesterone↗
PubMed2001

Final height in isolated GH deficiency type 1A: effects of 5-year treatment with IGF-I.

Data concerning final height (FH) in isolated growth hormone deficiency type 1A (IGHD1A) are scanty and controversial. In this paper we report the FH outcome of two girls with IGHD1A who were treated either with GH only (first patient) or with GH during the first 8 years and successively with IGF-I (second patient). In the first patient, FH was only slightly subnormal and slightly taller with respect to target height (TH). Surprisingly, FH was severely subnormal and very far from TH in the patient who underwent IGF-I therapy for >5 years: an auxological outcome similar to the one recently reported in the only two cases in the literature of patients with IGHD1A who have been treated with IGF-I until near FH achievement. We conclude that IGHD1A could have a very heterogeneous phenotypic expression in terms of FH and that IGF-I therapy, even though initiated some years before puberty onset and prolonged for more than 5 years, may not be able to ensure the normalization of height prognosis and the achievement of an FH close to TH.

Body Height↗
PubMed2001

Evaluation of the insulin resistance syndrome in 5- to 10-year-old overweight/obese African-American children.

OBJECTIVE: To characterize the insulin sensitivity of overweight and obese 5- to 10-year-old (Tanner stage 1-3) African-American children screened for participation in a diabetes prevention study and to identify the association of insulin sensitivity with obesity, hyperlipidemia, and hypertension. RESEARCH DESIGN AND METHODS: Measures of insulin resistance (homeostasis model assessment) and insulin sensitivity (Matsuda and DeFronzo's whole-body insulin sensitivity) were calculated from a 2-h oral glucose tolerance test in 137 African-American children recruited into a diabetes prevention study. Measures of lipids (LDL, HDL, total cholesterol, and triglycerides), blood pressure, and body composition were obtained for a subset of the children. RESULTS: In response to a glucose challenge, girls and older and heavier children produced significantly more insulin. As BMI increased, there was a statistically significant decrease in insulin sensitivity, particularly in girls. Insulin sensitivity was inversely correlated with increases in blood pressure, triglycerides, subcutaneous fat, the percentage of total body fat, and Tanner stage, but it was not correlated with LDL and HDL. CONCLUSIONS: Reduced insulin sensitivity and the cluster of risk factors known as the insulin resistance syndrome (IRS) are already apparent in these overweight African-American children. Young African-American girls, in particular, already show evidence of hyperinsulinemia in response to a glucose load, suggesting that the early stages of metabolic decompensation that lead to type 2 diabetes are already occurring. Monitoring of those risk factors known to be part of IRS should become part of routine medical care for overweight or obese African-American children.

Adipose Tissue↗
PubMed2001

Serum anti-p53 autoantibodies in patients with type 1 diabetes.

The presence of antibodies reacting with the p53 tumor suppressor protein has been described in patients with some autoimmune disorders. In this study we looked for serum anti-p53 antibodies in 64 patients with autoimmune type 1 diabetes mellitus within 4 mo of diagnosis. The presence of anti-p53 antibodies was observed in 6/64 (9.4%) subjects with type 1 diabetes, and in 1/44 (2.3%) subjects with other organ-specific autoimmune diseases (18 primary biliary cirrhosis, 10 autoimmune hepatitis, 16 thyroid diseases), but in none of 45 control subjects. No relationship was found between antibodies directed against islet- and non-islet-specific antigens and anti-p53 antibodies. These findings support a possible role for p53 in some autoimmune disorders.

Adolescent↗
PubMed2001

Cystinuria phenotyping by oral lysine and arginine loading.

BACKGROUND: Cystinuria is an inherited disorder of cystine and dibasic amino acids transport that results in urolithiasis because of poor cystine solubility. Three cystinuria phenotypes, differentiated according to urinary amino acid excretion in obligate heterozygotes, were regarded as allelic variants of a monogenic disease. Two mutated amino acid transporter genes, however, have been recently identified as responsible for cystinuria. Mutations in the SLC3A1 gene. encoding for the heavy subunit of the transporter protein rBAT, were associated with type I cystinuria, whereas type II and III cystinuria were associated with mutations in the SLC7A9 gene, encoding for a light subunit of rBAT. Lysine and arginine metabolism have, therefore, been evaluated in cystinuria homozygotes and heterozygotes to better define the cystinuria phenotypes and their correlations with these emerging genotypes. PATIENTS AND METHODS: Lysine and arginine intestinal absorption and renal excretion were assessed by oral loading and compared to normal controls. Seven cystinuria homozygotes and 7 obligate heterozygotes belonging to the different types received alternately an oral dose of 0.5 mmol/kg body weight lysine or arginine. Plasma concentrations of lysine, arginine, ornithine (derived from rapid arginine conversion) were measured 0, 1, 2, and 3 hours after loading. Their urinary concentrations were measured in morning urine and in urine collected 0-6 hours after loading. RESULTS: Gut lysine absorption was deficient in type II and III, and normal in type I cystinuria homozygotes. Impaired arginine intestinal absorption, as well as massive lysine, arginine, and ornithine hyperexcretion were shared by all homozygotes, irrespective of the type. All heterozygotes shared normal lysine absorption, whereas arginine absorption was slightly impaired in type II and III heterozygotes, which also displayed high lysine, arginine, and ornithine urinary excretion after loading. CONCLUSIONS: Two cystinuria phenotypes, type I and non-type I, can be identified in both homozygous and heterozygous cystinuric subjects by oral loading tests with lysine and arginine. In agreement with recent molecular findings, non-type I cystinuria comprises mentioned type II and type III, which constitute allelic variants of a cystine and dibasic amino acid transport disorder distinct from type I cystinuria.

Adolescent↗