Biomedical subjects

Antonella Petri

Publications and source records attributed to Antonella Petri.

6 recordsLinked to original sources

PubMed2006

A variation in a Pit-1 site in the growth hormone gene (GH1) promoter induces a differential transcriptional activity.

The proximal promoter of the human growth hormone gene (GH1) is highly polymorphic. We tested if promoter haplotypes differing at possibly functional sites, namely -278T/G (in the NF1 binding site), -75A/G (in the proximal Pit-1 binding site) and -57G/T (in the VDR binding site), induced a different luciferase activity when transfected in a rat pituitary cell line. The presence of a G instead of an A at position -75 induced a more than two-fold reduced activity (p<0.0001). In accordance with this findings the electrophoretic mobility shift assay demonstrated a reduced affinity of the -75G for the pituitary transcription factor Pit-1. Despite the strong effect of this polymorphism in vitro, the -75G variation was not associated to an impairment of the GH secretion in vivo.

Animals↗

PubMed2005

Kinetic and stability studies on the chloroperoxidase complexes in presence of tert-butyl hydroperoxide.

The inactivation of native chloroperoxidase (CPO) from Caldariomyces fumago in the presence of tert-butyl hydroperoxide (tert-BuOOH) was investigated. A kinetic analysis was made and the inactivation constants (V(3) and K(3)) were evaluated. In prolonged times, uni-exponential equation describes the enzyme time course inactivation. A method based on the rate of inactivation of the enzyme in the presence of the inactivating molecule tert-BuOOH was also performed. A second group of inactivation constants (j(3) and K) was obtained, which is sufficiently close to the first two, thus verifying that the decreasing of enzyme absorbance corresponds to the decay of activity.

Binding Sites↗

PubMed2005

A linearization method for low catalytic activity enzyme kinetic analysis.

A kinetic analysis was made and a linear plot based on the general rate equation derived by Laidler [Can. J. Chem. 33, 1614-1624] is proposed. This linearization method allows determining the kinetic parameters (K(m), k(cat)) and [E](0) for enzymes with low catalytic activity. The method was applied to chloroperoxidase from Caldariomyces fumago [EC 1.11.1.10], whose kinetic parameters K(m)(app), k(cat)(app), and [E](0) with monochlorodimedone as substrate, were obtained by using the linearization plot and the V(max) value (calculated by Eadie-Hofstee plot). This plot could also be useful to the study of abenzyme kinetics provided the concentration of the latter is either higher or equal than K(m) value.

Catalysis↗

PubMed2005

Traumatic brain injury-induced hypopituitarism in adolescence.

Childhood hypopituitarism may be present at birth or may be acquired. Young children and teenagers are particularly susceptible to TBI; in fact TBI is one of the first causes of death and disability in children older than one month of age since the most common cause of TBI is car crashes, including pedestrian-car and bicycle-car encounters, falls, child abuse, violence and sports injuries. Furthermore younger kids are more likely to have TBI due to falls while teenagers have more TBI than any other population from motor vehicle crashes. As reported for the adult patients hypopituitarism in adolescence should be suspected within an appropriate clinical context. In adolescents affected by TBI no experience about this condition has been reported but it is well known that treatment of hypopituitarism, in particular of GH deficiency, has multiple beneficial effects in addition to its promotion of linear growth and in particular in the transition phase. These include maintenance of normal body composition, structure function and metabolism through adult life. Therefore, the onset of TBI-induced GH deficiency in this particular phase of life should be strictly evaluated and corrected for the possible adult health consequences.

Adolescent↗

PubMed2004

Early treatment with GH alone in Turner syndrome: prepubertal catch-up growth and waning effect.

OBJECTIVE: In order to ascertain the advantages of early GH treatment in Turner syndrome (TS), we started a prospective study aimed at evaluating prepubertal height gain in a cohort of 29 girls who were treated with the same pro-kilo GH dose (1.0 IU/kg per week) since they were less than 6 years old and for at least 5 years before entering puberty. PATIENTS AND DESIGN: Following a minimum of 6 months of baseline observations, 29 girls with TS were enrolled for this prospective study provided that they (a) were less than 6 years old, (b) were below -1.0 standard deviation score (SDS) for height, (c) had a projected adult height (PAH) lower than the respective target height (TH) and (d) had a height velocity (HV) lower than -1.0 SDS. All the selected girls underwent a 5-year treatment with biosynthetic GH at a stable dose of 1.0 IU/kg per week and were periodically measured during the treatment period in order to evaluate height, HV and PAH. RESULTS: After a dramatic acceleration during the 1st year, HV was attenuated during the subsequent years, reaching its nadir at the 5th year. Height deficiency under therapy progressively decreased from entry onwards, shifting from -2.4+/-0.7 to -1.0+/-1.2 SDS. In the same period, mean PAH progressively increased, although after 5 years it remained lower than the average TH. CONCLUSIONS: (a) An effective growth-promoting strategy in TS should be based on early GH treatment, as suggested by our results. (b) This strategy could result in a prepubertal normalization of height, thus allowing the appropriate timing for the induction of puberty. (c) An initial GH dose of 1.0 IU/kg per week may be suitable during the first years of therapy, as shown by our data documenting an important waning effect of GH therapy only after the 4th year of treatment. (d) No acceleration of bone maturation was observed under this treatment regimen.

Body Height↗

PubMed2002

Prevalence and clinical picture of celiac disease in Turner syndrome.

A multicenter study of Turner syndrome (TS) patients was carried out to estimate the prevalence of celiac disease (CD) and to detect clinical characteristics and laboratory data of affected patients. Three hundred eighty-nine girls with TS were screened by IgA antigliadin antibodies and/or antiendomysial antibodies. Intestinal biopsy was offered to positive cases. CD was diagnosed in 25 patients. In celiac subjects, anemia, anorexia, and delayed growth (with respect to Italian TS curves) were frequently present; whereas distended abdomen, chronic diarrhea, constipation, and vomiting occurred more rarely. In addition, low serum iron levels, hemoglobinemia, and high values of aminotransferases were observed. Ten patients showed classic CD, 8 showed atypical symptoms, and 7 showed a silent CD. In 11 symptomatic patients, the diagnosis of CD was made at the onset of symptoms, whereas 7 of them showed a median delay of 79 months in diagnosis. Other autoimmune disorders were observed in 40% of the patients. Our study confirms the high prevalence (6.4%) of CD in a large series of TS patients. Moreover, the subclinical picture in 60% of the cases, the diagnostic delay, and the incidence of other autoimmune disorders suggest that routine screening of CD in TS is indicated.

Adolescent↗