F Schettini

Post‐natal Development of Protein C in Full‐term Newborns

ABSTRACT. 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.

Effectiveness of Thymostimulin and Study of Lymphocyte-Dependent Antibacterial Activity in Children with Recurrent Respiratory Infections

Recurrent respiratory infections (RRI) consist of more relapsing acute respiratory infections than the ones expected for the age [> 6 acute respiratory tract infections (RTI) per year if age is > 3 years, and > 8 acute RTI per year if age is < 3 years]. Concerning the pathogenesis of RRI, several investigations report the important role of environmental factors, early socialization and immunological dysfunctions, such as lymphocyte subpopulations alterations, IgG subclass deficiency and phagocytosis and/or opsonization deficit during acute infections. In this framework, we have studied the lymphocyte-dependent antibacterial activity (ABA) among 121 children affected by RRI. Results show a statistically significant alteration of this function in 38 children (31.4%): 19 of them exhibited an absent ABA (group 1), while in the others same function was reduced (group 2). A bovine thymic extract, thymostimulin, was administered to both groups by intramuscular injections (1 mg/kg) for a 3 month cycle. At the end of therapy we observed a statistical significant rise of ABA only in group 1 and among children aged > 3 years. Among the same patients, 33 children (86.8%) improved in terms of reduction of clinical score and better results were seen among children aged > 3 years. These data emphasize the beneficial role of thymostimulin in RRI-affected children, suggesting a transient immaturity of the immune system as one of the possible pathogenetic factor.

Resistance to activated protein C in thalassaemic patients: an underlying cause of thrombosis

Abstract: We evaluated 81 thalassaemia major and 4 thalassaemia intermedia patients (48 M, 37 F), median age 17 years; 62/85 patients were HCV‐positive, 3/85 HIV‐positive, 19/85 were splenectomized. Forty normal healthy children were recruited as the control group. The number of thrombotic events was studied retrospectively. Platelet poor plasma was filtered and quick‐frozen at ‐70°C until time of assay. APC resistance was measured in an activated thromboplastin time and results were expressed as normalized ratio. All tests were done with diluted 1 in 5 (v/v) factor V deficient plasma and with undiluted plasma. Molecular genetic investigation of factor V gene was performed with polymerase chain reaction, followed by digestion of amplified products with restriction enzyme Mnl I. Data obtained with molecular investigation revealed the presence of 4 heterozygous subjects for factor V Leiden (4.7%). Functional tests were able to detect all heterozygotes for factor V Leiden both with undiluted and with diluted plasma, and there were no false negative subjects. However, undiluted plasma revealed a greater number of false positive subjects (n = 15) than did diluted plasma. Therefore, tests done with undiluted and diluted plasma revealed a 100% sensitivity, while specificity was 81 % for undiluted plasma and 97% for diluted plasma. Only one thrombotic event was observed in one of the 85 studied patients, as a case of stroke in a thalassaemia intermedia patient with APC resistance. In the same patient an additional thrombogenic risk factor was represented by a pronounced haematocrit increase at the beginning of her tranfusion regimen.

Preprothrombin and Prothrombin in Full-Term Newborns

Three activities of factor II (prothrombin, prothrombin-coagulase and antigenic activity) have been evaluated in full-term newborns on the first 5 days of life. Prothrombin activity is similar to prothrombin-coagulase activity on the 1st day of life and on the 3rd day the two activities decrease simultaneously. The prothrombin activity rises again towards the 5th day, contrary to the prothrombin-coagulase activity which continues to decrease. If vitamin K1 is not administered, the decrease in the two activities on the 3rd day is more marked. The antigenic activity of factor II does not show significant variations from the 1st to the 5th day of life; it always remains inferior to the values observed in adults.

Plasma protein Z levels in healthy and high-risk newborn infants

Aim: To evaluate plasma protein Z (PZ) levels in healthy and high‐risk newborn infants. Methods: A longitudinal observational study was conducted. Inclusion criteria were: healthy term and pre‐term newborns normal for gestational age and newborns belonging to one of the following groups: newborns small for gestational age (SGA), newborns affected by respiratory distress syndrome (RDS), newborns from mothers with pre‐eclampsia. Newborns with sepsis, congenital malformation or haemorrhagic disorders were excluded. Plasma PZ levels, protein C (PC) concentration, PC activity and protein‐induced vitamin K absence levels were measured. Results: 53 newborns were enrolled into the study. PZ and PC antigen levels varied significantly among analysed subgroups on day 1 (p < 0.01): lower levels of these inhibitors were found in RDS newborns (group C), newborns from mothers affected by pre‐eclampsia (group D) and SGA newborns (group E) than in healthy term and preterm newborns (groups A and B).

Post-Natal Development of Factor II (Pre-Prothrombin and Prothrombin) in Man

Postnatal development of factor II molecule has been evaluated by three different methods in infants and children from 15 days to 7 years of age. The immunochemical determination of factor II showed that the plasma levels of this factor reached the lowest adult values between 4-7 months of age and rose slowly for all the first year; after this age the plasma concentration was steady. The adult range was reached from 15 to 120 days of age when the factor II was evaluated by the method of Owren and Aas (19) and by staphylocoagulase reagent.

POST‐NATAL DEVELOPMENT OF FACTOR IX

Abstract. Schettini F., De Mattia D., Altomare M. and Montagna O. (University of Bari, Institute of Child Health, Bari, Italy). Postnatal development of factor IX. Acta Paediatr Scand, 69: 53, 1980.—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 in Factor 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

A Transverse and Longitudinal Study of Pancreatic Function and Glucose Tolerance in Thalassemic Patients

Poly transfused thalassemia major (Th) patients show a high prevalence (frequently reported > 50%) of impairment of β-pancreatic function (PF) and of overt diabetes mellitus (10–25%). The impairment of liver function, the hyperinsulinemia following insulin resistance, the hyperglucagonemia, the β-pancreas exhaustion, the genetic predisposition, and the increased frequency of viral infections could play a role in the pathogenesis of the PF derangement [1–7]. The prevalence of diabetes mellitus has been reported to be lower in regularly (16%) than in irregularly (23%) ironchelated Th patients [7]. In this retrospective transverse and longitudinal study we have evaluated the effect of the improvement of chelation and transfusion protocols on the prevalence of PF and of impaired glucose tolerance (GT) in Th patients.

Cytochrome b and FAD content in polymorphonuclear leucocytes in a family with x-linked chronic granulomatous disease

Chronic granulomatous disease (CGD), an immunodeficiency syndrome characterized by extreme susceptibility to bacterial infections, is due to a defect of the respiratory burst in human phagocytes. NADPH oxidase, the enzyme that catalyzes the reduction of oxygen and the release of oxidative radicals, was studied in polymorphonuclear leucocytes (PMNs) in a family affected by an x‐linked inheritance form at high penetrance of the disease. The contents of cytochrome b, suggested as the terminal component of the oxidase electron transport chain, and FAD, the hypothetical proximal component of the chain, were determined in patients and in carriers. Cytochrome b showed the typical behaviour of x‐linked CGD: total absence in patients, intermediate values in carriers. FAD content evaluated on plasma membranes was less decreased than cytochrome b. Carriers also showed a decrease of this flavoprotein. Cytochrome b and FAD contents were compared to NBT test and superoxide production: a clear correlation was observed for the cytochrome b, but FAD plasma membrane evaluation could also be an interesting tool for the metabolic characterization of the disease in patients and in carriers.

ACID LYSIS OF RED BLOOD CELLS IN NORMAL CHILDREN

Acid lysis of foetal red cells has been investigated by means of an automated procedure with the Fragiligraph.