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G Bona

Publications and source records attributed to G Bona.

At least 55 records · Page 3Linked to original sources
PubMed2002

[Secular trend of puberty].

The aim of our study was to evaluate the age of the onset of pubertal characteristics in a population of Northern Italy and to compare our data with the pubertal staging scale defined by Tanner in 1976. These observations may help us to verify if even in Italy there is a positive secular change in sexual maturation, as has been observed in many European countries. We studied 3510 children (1868 males and 1642 females) aged 6-15 years, born between 1983 and 1996. In every subject sexual maturity was evaluated according to Tanner stages. We calculated the percentile distribution for ages of attainment of B2 and PH2 stages for females and G2, PH2 and testicular volume = or >4 ml (VT4) for males. In females the percentile values for B2 were: 3rd=8.1, 50th=10.5, and 97th=12.6 years. In males the percentile values for G2 and VT4 were: 3rd=8.8 and 9.1 years respectively, 50th=11 years, and 97th=13.4 and 13.3 years respectively. 3rd, 50th, and 97th centiles for pubic hair stage 2 were 8.1, 10.6 and 12.6 years for females and 8.8, 11.2 and 13.4 years for males. For all stages an earlier pubertal development was seen in comparison with Tanner data. One hundred-twenty-five girls had already reached menarche. Median (interquartile range) age at menarche was 11.9 (11.4-12.4) years showing a decrease compared with Tanner values. Our data clearly demonstrate a positive secular trend in pubertal development and point out the need of having updated references values of the timing of sexual maturation for the whole Italian population.

Adolescent↗
PubMed2001

Mechanisms of the renal vasodilation caused by insulin in anesthetized pigs.

The present study was planned to determine the mechanisms involved in the renal vasodilation caused by insulin. Changes in flow caused by the intravenous infusion of 0.004 IU/kg/min of insulin at constant heart rate, aortic blood pressure, left ventricular contractility and blood levels of glucose and potassium in the left renal artery were assessed using an electromagnetic flowmeter. In ten pigs, infusion of insulin caused an increase in renal blood flow which averaged 12.8% of the control values. After hemodynamic variables had returned to control values, insulin infusion was repeated in five pigs following blockade of alpha-adrenergic receptors with injection of phentolamine into the renal artery and in the other five pigs following blockade of nitric oxide formation with injection in the same artery of Nomega-nitro-L-arginine methyl ester (L-NAME). After blockade of alpha-adrenergic receptors, insulin infusion caused an increase in renal blood flow which averaged 18.1% of the control values, being significantly enhanced with respect to the increase previously obtained in the same pigs. On the contrary, after blockade of nitric oxide formation insulin infusion caused a decrease in renal blood flow which averaged 6.5% of the control values. These responses were respectively abolished by the subsequent injection into the renal artery of L-NAME and phentolamine. The present study showed that the renal vasodilation caused by insulin in the anesthetized pig was the result of two opposite effects which involved a predominant vasodilation mediated by the release of nitric oxide from the endothelium and a sympathetic vasoconstrictor mechanism mediated by alpha-adrenergic receptors.

Animals↗
PubMed2001

Accuracy of fine needle aspiration biopsy of thyroid nodules in detecting malignancy in childhood: comparison with conventional clinical, laboratory, and imaging approaches.

In childhood the traditional diagnostic approach to thyroid nodules consists of clinical, laboratory, and imaging evaluations. A safe and accurate procedure is needed to promptly identify patients who require surgery. In regard to the usefulness of fine needle aspiration biopsy, the data in the literature concerning children and adolescents are scanty. The aim of this study was to evaluate and compare the diagnostic accuracies of clinical, laboratory, and imaging data collected retrospectively in a group of pediatric patients with thyroid nodules submitted to fine needle aspiration biopsy. Forty-two patients who underwent surgery for thyroid nodules, recruited in 9 Italian pediatric endocrine units, were retrospectively studied. According to histological diagnosis, they were divided into 2 groups, 22 patients with benign lesions and 20 patients with malignant lesions. From clinical records we obtained data about 1) symptoms of neck compression; 2) cervical adenopathy; 3) thyroid function, calcitonin level, and antithyroid antibody titers; 4) ultrasonography; 5) (99m)Tc scintiscanning; and 6) cytology obtained with fine needle aspiration biopsy. Patients and nodule characteristics were analyzed statistically for associations with the presence of thyroid cancer. Among clinical findings, only adenopathy was significantly higher in the group with cancer (8 of 22 benign lesions vs. 16 of 20 malignant lesions; P = 0.006). Thyroid function and antibody titers were similar in the 2 groups, whereas the serum calcitonin level was elevated only in 1 patient with malignant lesions. Among ultrasonography findings, no significant statistical difference was found between the 2 groups with regard to number, dimensions, growth progression, or hypoechogenic pattern of the nodules. Regarding scintigraphic findings, no significant difference was found between the 2 groups. However, a positive correlation (r = 0.90; P < 0.0001) was found between fine needle aspiration biopsy cytological findings and histological diagnoses. The sensitivity, specificity, and accuracy of fine needle aspiration biopsy were 95%, 86.3%, and 90.4%, respectively. A multiple regression analysis showed that only fine needle aspiration biopsy (beta coefficient = 0.963; P < 0.0001) significantly contributed to detecting malignancy (multiple r = 0.973; P < 0.0001). This study provides strong evidence that fine needle aspiration biopsy is a safe technique even in childhood and adolescence, offering the best sensitivity, specificity, and accuracy in detecting malignancy compared with conventional approaches.

Adolescent↗
PubMed2001

Isolated growth hormone deficiency in children and adolescents.

Although it is difficult to reach international agreement on the definition of growth hormone deficiency (GHD) in children and adolescents, great efforts to do so have been made during the last two decades. A somewhat limited definition of GHD is: a combination of auxological, clinical, biochemical and metabolic abnormalities caused by lack or insufficiency of GH secretion that results in a decrease in the production of GH-dependent hormones and growth factors. Its aetiology is very complex. Therefore, specific studies must be performed during different periods of childhood (neonatal, prepubertal and pubertal periods). Auxological parameters, particularly growth velocity (GV), are still considered the best clinical measures for analysing human growth. The spectacular advances in our understanding of molecular biology during the past twenty years have allowed, and will continue to allow, a more and more precise diagnosis of the molecular anomalies of human growth. This will, in turn, allow changes caused by genetic lesions to be more efficiently distinguished from those due to nutritional, organic, tumoural, psychological or traumatic causes. Our knowledge of the molecular bases of undergrowth due to a deficiency in GH has developed as a result of the localisation and characterisation of human genes which code for proteins implicated in the hormonal regulation of growth. These genes include pituitary GH (GH1), pituitary transcription factor 1 (Pit-1), the prophet of Pit-1 (PROP-1), the pituitary transcription factor LHX3, the transcription factor HESX1 and the GH-releasing hormone receptor (GHRHr). In addition, magnetic resonance imaging is the best available imaging method for the evaluation of size and structure of the pituitary and the parasellar region.

Adolescent↗
PubMed2001

Defective function of Fas in patients with type 1 diabetes associated with other autoimmune diseases.

Fas (CD95) triggers programmed cell death and is involved in cell-mediated cytotoxicity and in shutting off the immune response. Inherited loss-of-function mutations hitting the Fas system cause the autoimmune/lymphoproliferative syndrome (ALPS). We have recently shown that ALPS patients' families display increased frequency of common autoimmune diseases, including type 1 diabetes. This work evaluates Fas function in type 1 diabetic patients without typical ALPS. Cell death induced by anti-Fas monoclonal antibody was investigated in T-cells from 13 patients with type 1 diabetes alone and 19 patients with type 1 diabetes plus other autoimmune diseases (IDDM-P). Moreover, we analyzed 19 patients with thyroiditis alone (TYR), because most IDDM-P patients displayed thyroiditis. Frequency of resistance to Fas-induced cell death was significantly higher in patients with IDDM-P (73%) than in type 1 diabetic (23%) or TYR (16%) patients or in normal control subjects (3%). The defect was specific because resistance to methyl-prednisolone-induced cell death was not significantly increased in any group. Fas was always expressed at normal levels, and no Fas mutations were detected in four Fas-resistant IDDM-P patients. Analysis of the families of two Fas-resistant patients showing that several members were Fas-resistant suggests that the defect has a genetic component. Moreover, somatic fusion of T-cells from Fas-resistant subjects and the Fas-sensitive HUT78 cell line generates Fas-resistant hybrid cells, which suggests that the Fas resistance is due to molecules exerting a dominant-negative effect on a normal Fas system. These data suggest that Fas defects may be a genetic factor involved in the development of polyreactive type 1 diabetes.

Adolescent↗
PubMed2001

Turner's syndrome.

Turner syndrome (TS) is the most common sex-chromosome abnormality in females. Short stature and hypogonadism are the classical clinical findings. The spontaneous final height (FH) ranges between 139 and 147 cm, representing a growth deficit of about 20 cm with respect to the unaffected population. GH therapy improves FH and should be started during childhood at a high dose of about 1 IU/kg/week (range 0.6-2 IU/kg/week). Some authors advocate combined therapy with an anabolic steroid at various doses (e.g. oxandrolone 0.05-0.1 mg/kg/day). This treatment results in a significantly increased FH, a large proportion of treated girls reaching a FH of more than 150 cm. Gonadal function is compromised during adolescence in about 80% of girls with TS, whilst in about 20% pubertal development occurs spontaneously. Oestrogen therapy should be started at the age of 13-14 years in hypogonadic patients; early onset of treatment (before 12 years) seems to compromise FH. Other concerns in these patients are fertility and osteopenia.

Adolescent↗
PubMed2001

Infants of immigrant parents in Italy. A national multicentre case control study.

BACKGROUND: The aim of this study was to evaluate health state of newborns of immigrated parents from developing countries. METHODS: Hospital records of 69,605 infants born during 1996/1997 in Italy were reviewed comparing, in a case-control study, each infant of immigrated parents to two infants born immediately before and after to Italian parents. RESULTS: Of the 69,605 newborns 3906 (5.6%) were born to immigrated parents. This prevalence prolongs the increasing trend observed during the last 10 years of infants born to immigrated parents and reduces the fall of the birth rate linked to the few infants born to Italian parents. It was influenced by geographical factors, being higher in Northern-Central Italy (7%) than in Southern and Insular Italy (2.8%), as consequence of more elevated incomes in these Italian regions. The origin countries of immigrated parents were mainly Northern Africa (31.7%), Eastern Europe (18%) and Sub Saharan Africa (11.6%). Infants of immigrated parents showed higher incidences of prematurity, low birth weight, asphyxia and neonatal mortality rate than newborns with Italian parents. These higher incidences appeared related to some risk factors such as higher parity, short gestational age, some maternal infections, maternal drug dependence, maternal age less than 18 years, low familiar income, inadequate obstetric cares, difficulty to accessing the public health services. CONCLUSIONS: The health problems of infants with immigrated parents are mainly related to social disadvantage and can be overcome improving the social state, the lifestyles and the obstetric cares of the immigrated women, so as monitoring their risk pregnancies.

Adolescent↗
PubMed2001

[Air pollution in the daily environment: study of a school-children population].

BACKGROUND: To evaluate the annual distribution of personal exposure to NO2 in a sample of school children and to study the determinants of such exposure. METHODS: Exposure to NO2 has been evaluated using Palmes Tubes in 310 school-children (aged 5-14) in Novara. The possible differences in personal measurements by means of ANOVA and Tuckey test were evaluated. Information on the sources of potential exposure and on respiratory symptoms have been collected through a questionnaire and a clinical diary. The relative risk for these variables has been assessed using a multiple regression model (Logit). RESULTS: The annual mean of the 6,200 measurements was 42.3 microgram/m3, with a significant difference among seasons and with higher values in winter. The only factor associated with a high exposure was identified for maternal school children living in houses close to high traffic density roads. Respiratory symptoms were non-related to NO2. CONCLUSIONS: The use of gas cookers and heaters is not enough to explain the variability of personal exposure. Between other specific determinants, the importance of living along busy streets, of ETS and of seasons explains the level of personal exposure. The opportunity of personal, rather than environmental, monitoring is confirmed, even if we stress the necessity of studying the short-term exposure to rapidly find clinical damages in the general population.

Air Pollution, Indoor↗
PubMed2000

A systematic review of Helicobacter pylori eradication treatment schedules in children.

METHODS: We systematically reviewed all available data in the paediatric literature on treatment for Helicobacter pylori infection to determine overall efficacy of different schedules. A comprehensive search of all published articles and letters from 1987, and of abstracts presented at three main meetings on this topic between 1997 and 1999, was carried out. Results from all English and French papers, letters and abstracts were extracted and analysed. RESULTS: Only 30 full articles and 16 abstracts were found, with results on eradication of H. pylori in 870 and 1552 children, respectively. Monotherapy or dual therapy with an antisecretory drug plus one antibiotic showed a very low efficacy. Dual therapies with bismuth plus one antibiotic (either amoxycillin or a nitro- imidazole) or two antibiotics when administered for 2 or more weeks were as effective as either bismuth-based or proton pump inhibitor-based triple therapies. Triple therapies were less effective than in adults, and while bismuth-based triple therapies were more effective when given for 2 weeks than for one week, proton pump inhibitor-based triple therapies have a similar efficacy irrespective of the duration. CONCLUSION: In children dual therapies seemed as effective as triple therapies, and longer courses of proton pump inhibitor-base triple therapies are not better than shorter ones.

Anti-Bacterial Agents↗
PubMed2000

Precocious puberty in immigrant children: indications for treatment.

Immigration from developing countries to Europe has greatly increased during the last few years. Very little information is available on children who immigrated with their biological family, thus this paper deals only with children immigrating by adoption. In recent years some studies have shown an increased incidence of precocious puberty among adopted children, but information on this issue is scanty. Several hypotheses have been put forward to explain precocious puberty in adopted children, including nutritional, ethnic and/or emotional factors. Untreated precocious puberty is associated with short stature and has social and psychological consequences in addition to those related to adoption. Therefore, indications for therapy need to be carefully planned. In adopted children age estimation is a possible source of error in timing of puberty as date of birth is often missing or inaccurate. Thus each child must be carefully evaluated.

Adoption↗
PubMed2000

The role of nitric oxide in the coronary vasoconstriction caused by growth hormone in anaesthetized pigs.

Intravenous injection of growth hormone in anaesthetized pigs has been shown to cause coronary vasoconstriction by antagonizing the vasodilatory effects of 2-adrenergic receptors. Because nitric oxide is believed to modulate or mediate 2-adrenergic effects, the present study was undertaken in the same experimental model to determine the role of nitric oxide in the above response to growth hormone. In fourteen pigs anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary blood flow caused by intravenous injection of 0.05 i.u. kg-1 of growth hormone at constant heart rate and arterial blood pressure were assessed using electromagnetic flowmeters. In a first control group of six pigs, growth hormone caused a decrease in coronary blood flow which averaged 13.1 % of the baseline values. In a second group of eight pigs, intravenous administration of N-nitro-L-arginine methyl ester (L-NAME) was used to block the endothelial release of nitric oxide. In these pigs, the subsequent injection of growth hormone did not cause any significant changes in coronary blood flow, even when performed after reversing the increase in arterial blood pressure and coronary vascular resistance caused by L-NAME with continuous intravenous infusion of papaverine. These results indicated that the coronary vasoconstricting effect of growth hormone, known to involve antagonism of 2-adrenergic vasodilatory effect, was mediated by inhibition of nitric oxide release.

Animals↗