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Biomedical subjects

M Altomare

Publications and source records attributed to M Altomare.

At least 19 recordsLinked to original sources

Association of congenital afibrinogenemia and K-dependent protein C deficiency--a case report.

The authors describe a rare case of congenital afibrinogenemia with concomitant K-dependent protein C deficit that was brought to our observation for ischemic lesions of the foot in association with fibrinogen concentrate infusions. These lesions can be attributed to the association of various factors: fibrinogen infusion without heparin coverage, microtrauma, and protein C (PC) deficit. In fact, thromboembolic complications during afibrinogenemia were previously reported usually in association with substitutive therapy, and it is also known that PC deficit predisposes to thrombotic complications. The the authors' knowledge, the case described by them is the first in which PC deficit is associated with afibrinogenemia. This association cannot be explained by a common genetic mechanism because the genes for fibrinogen and for protein C are located on different chromosomes (chromosomes 4 and 2 respectively).

Adolescent

Thromboembolic risk in children with nephrotic syndrome.

The in vivo activation of the hemostatic system was evaluated in 14 children (4-13 years old) with nephrotic syndrome at different stages of the disease. The blood platelet count, beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), fibrinogen, the coagulation inhibitors antithrombin III and protein C (ATIII:Ag and PC:Ag), and D-dimers were determined. Platelet number was significantly higher at the onset of the disease than in the next stages (p less than 0.05). beta-TG, PF4 and fibrinogen were significantly increased as compared with controls at the onset (p less than 0.001) and decreased progressively during the course of the disease without reaching the control values. Blood coagulation inhibitors behaved differently; PC was higher in patients than in controls at all stages (p less than 0.05) whereas ATIII values were significantly decreased at the onset (p less than 0.05), but increased during the course the disease (p less than 0.01). No changes were observed in the D-dimer plasma levels. These data suggest that the thrombotic risk in nephrotic syndrome is particularly evident at the onset of the disease, and appears to be due mainly to changes in platelet number and function, and to increased fibrinogen levels rather than to alterations of plasma anticoagulant factors.

Adolescent

Age-specific prevalence of hepatitis B virus infection among children in an endemic area in southern Italy.

In 1989 the prevalence of hepatitis B virus markers was studied by radioimmunoassay in a sample of 1,426 healthy children, 3 to 11 years old, attending kindergarten and the primary schools in a large urban area of the Apulia Region in Southern Italy, where the hepatitis B surface antigen (HBsAg) prevalence among pregnant women is 5.6%. The overall prevalence of any hepatitis B virus marker was 3.4%, increasing from 1.7% in 3- to 5-year-old children to 5% in 10- to 11-year-old children (P less than 0.002). Prevalence was not associated with the father's years of schooling (odds ratio, 1.98; confidence interval, 95% (0.9 to 4.6] or with the family size (odds ratio, 2.96; confidence interval, (0.7 to 11.8]. The overall HBsAg prevalence was 0.8, a rate that was lower than the 5.6% found in pregnant women. The finding of only 12 HBsAg-positive children of the 1,426 tested, despite 80 of them being born to HBsAg-positive carrier mothers (on the basis of the 5.6% HBsAg prevalence among pregnant women), is probably attributable to the low proportion (5%) of hepatitis B e antigen positivity among the HBsAg-positive carrier mothers in the study area. The observed low HBV infection rate in younger age groups, which confirms recent studies in other areas of Italy, appears to be the result of several factors: improved socioeconomic conditions; decreased family size; and increased use of disposable syringes in the last few years.

Age Factors

Coagulation contact phase factors and inhibitors in beta-thalassemia major children.

Selected hemostatic parameters of 23 children affected by beta-thalassemia major were studied and compared to an age- and sex-matched group. Plasma prekallikrein level was reduced in all patients, splenectomized or not. In splenectomized patients, platelet count and in vitro platelet aggregability were significantly increased and Protein C was slightly increased. The activated partial thromboplastin time was prolonged and the normotest reduced. Finally, a reduction in the plasma levels of fibrinogen and of vitamin K-dependent proteins, including the antithrombotic Protein C, was observed in nonsplenectomized patients. Our data indicate that the hemostatic system in patients with thalassemia major may be altered. The relationship between these laboratory changes and clinical manifestations remains to be established.

Adolescent

Post-natal development of protein C in full-term newborns.

The purpose of this study was to determine the concentration of Protein C in the blood of full-term healthy newborns. The levels of Protein C, evaluated by electroimmunoassay, were low in the first 5 days of life and lower than the critical adult thrombotic level. The antigenic activity increased progressively from the 2nd week of life and the adult values were reached after the 6th month. The reduction of Protein C levels may impair the ability of the newborn to control consumptive disorders, thus exposing the infants to the risk of thrombotic conditions in neonatal age.

Age Factors

Mechanism of altered drug binding to serum proteins in pregnant women: studies with valproic acid.

The mechanism underlying the impaired serum protein binding of valproic acid (VPA) in pregnancy was examined in samples collected from 24 healthy women in the last 3 weeks of gestation and 15 age-matched nonpregnant female controls. Experiments were performed in vitro using a rapid equilibrium dialysis technique free from in vitro alterations in free fatty acids (FFA). At a total drug concentration of approximately 420 mumol/L, the free VPA fraction was 10.2 +/- 2.9% (SD) in pregnant women and 4.8 +/- 1.0% in controls (p less than 0.001). Pregnancy was associated with a marked reduction in serum albumin levels but with only a slight, nonsignificant elevation in FFA. Free VPA fraction was negatively correlated with serum albumin levels. A positive correlation between free VPA fraction and FFA was observed in the pregnant group but not in the controls. The only sample collected during labour showed a striking elevation of both free VPA fraction and FFA, in spite of a normal albumin concentration. Scatchard's plots showed VPA bound to two classes of binding sites on the albumin molecule. The number of primary (n1) and secondary (n2) binding sites in pregnant women (n1 = 2.0; n2 = 10.7) was virtually identical to that observed in the controls (n1 = 1.9; n2 = 9.8). The association constants of the primary (k1) and secondary (k2) sites were lower in pregnant women (15.9 X 10(3) and 0.19 X 10(3) L/mol, respectively, vs. 22.6 X 10(3) and 0.33 X 10(3) L/mol in controls) but the difference was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Differential transplacental binding of valproic acid: influence of free fatty acids.

The unbound fraction of valproic acid (VPA) was found to be significantly lower in cord serum (6.0 +/- 0.8%) than in maternal serum collected before oxytocin (12.2 +/- 2.7%) or after delivery (9.9 +/- 2.3%). The difference was probably due to the concentration of free fatty acids (acting as displacing agents) being higher in maternal serum. The transplacental binding gradient explains the clinical observation that total VPA levels at delivery are higher in the newborn than in the mother.

Dialysis

Endocrine involvement in children with beta-thalassaemia major. Transverse and longitudinal studies. I. Pituitary-thyroidal axis function and its correlation with serum ferritin levels.

Thyroid function was investigated by a TRH test in 24 clinically prepubertal children, 3-15 years old with beta-thalassaemia major; in 7 of them the test was repeated once and in 2 twice at intervals of at least 12 months. Basal T4, T3, TBG and TSH levels and the TSH levels during a TRH test were determined and correlated with age and serum ferritin levels. Basal serum T4, T3 and TBG levels were lower and serum TSH levels were higher during the test and in the basal state in thalassaemia major children than in control children. These results show a compensated sub-clinical primary hypothyroidism. The transversal study did not show any significant correlation between the hormonal parameters studied and chronological age or serum ferritin levels. In contrast, the longitudinal study showed a significant correlation between pituitary-thyroidal axis function and siderosis (positive correlations between the variations of TSH levels as delta, peak, 30 and 45 min values and the variations of serum ferritin levels). The thyroid impairment seems not to be correlated with serum ferritin levels in the transversal study because of the presence of an individual different sensitivity of the gland to the iron overload. The ferritin dependence of this impairment is shown only by longitudinal studies where individual differences in sensitivity of the gland are absent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Endocrine function in four anencephalic infants.

Endocrine studies of 4 anencephalic infants were carried out. No hypothalamic or hypophyseal structures could be found in any of them macroscopically, but we cannot say that there were no functioning pituitary cells which might have been seen microscopically. A combined LH-RH and TRH test was performed in the 6th h of life, followed by an intravenous glucose tolerance test 1 h later. Our data suggest that: (1) adenohypophyseal tissue, present in anencephaly even in the absence of a hypothalamus, is able to synthesize PRL and TSH autonomously and, under specific stimulation, PRL, TSH, and ACTH can be released while FSH and LH-HCG are not, hGH secretion is doubtful; (2) the circulating hGH and TSH surges that normally occur after delivery are hypothalamus-dependent and do not occur in anencephalics; (3) the thyroid and adrenals are able to synthesize hormones when specifically stimulated, even in the absence of the hypothalamus, and (4) beta-pancreatic function is not markedly impaired in anencephaly.

Anencephaly

Delayed decrease in serum ferritin in polytransfused children with thalassemia major after continuous subcutaneous infusions of desferrioxamine.

A longitudinal study has been conducted on serum ferritin concentrations in children with thalassemia major treated with desferrioxamine (DFO), both intramuscularly and by continuous subcutaneous infusion, in order to evaluate the time interval after which iron chelation becomes effective. In a first group of 19 children, treated intramuscularly with DFO at a dose of 20 mg/kg for 20 days a month, ferritin levels were followed for 739 days and a progressive increase with a significant linear correlation with time was seen. The daily increase was calculated to be 8.53 +/- 1.95 ng/ml. In the second group of 12 children treated with DFO by continuous subcutaneous infusion (greater than or equal to 20 mg/kg/day for 6 days a week), the increase in ferritin was markedly lower, the mean daily value being 4.77 +/- 3.30 ng/ml. Only after the first 360 days of treatment did the serum ferritin decrease, by 1.95 +/- 3.32 ng/ml/day, in spite of a mean daily iron contribution from blood transfusions of 7.09 +/- 2.69 mg/day. These changes in serum ferritin led us to conclude that one can only expect to obtain a decrease in the body's iron overload after more than a year of treatment with subcutaneous DFO.

Blood Transfusion

Post-natal development of factor IX.

Post-natal development of clotting activity and of antigen level of Factor IX was evaluated in 111 healthy, breastfed, newborn infants, aged 1-30 days. Of these, 80 had received at birth 2 mg of vitamin K1 orally. Factor IX clotting activity was determined by one-stage assay and antigen level by electroimmunoassay. On the 1st day both antigen level and clotting activity were low and the ratio was 1.01. There was a significant postnatal increase of the two activities of Factor IX during the first three days of life; thereafter both remained constant. No statistical difference inFactor IX activity was found with oral administration of vitamin K1 after the birth. During the first month of life both clotting activity and antigen level of Factor IX were low as compared to adult values. There was no correlation with age. The Factor IX protein of newborns did not show molecular heterogeneity by crossed-immunoelectrophoresis.

Antigens