[The concomitant presence of prohemorrhagic and thrombophilic changes in coagulation factor V: a severe defect of coagulant activity and homozygote resistance to activated protein C]. / Presenza concomitante di alterazioni proemorragiche e trombofiliche del fattore V della coagulazione: difetto grave di attività coagulante e resistenza omozigote alla proteina C attivata.

We describe the peculiar and concomitant presence of a severe coagulation defect predisposing to bleeding and a mutation associated with inherited thrombophilia. A 6-year-old boy had a severe deficiency in factor V procoagulant activity and antigen and yet remained asymptomatic. This paradox might be explained by the hypothesis of the simultaneous presence of a thrombophilic disorder that might have restored hemostatic balance. The boy was a homozygous carrier of the Arg506Gln mutation of coagulation factor V, that renders this factor resistant to inactivation by its naturally occurring inhibitor, activated protein C. The family members, none of whom had bleeding or thrombotic symptoms, were heterozygotes for either the bleeding or the thrombophilic defect. Despite the severity of the bleeding defect, the absence of bleeding symptoms in the boy can be explained by the hypothesis that any residual amount of factor V present in his plasma is resistant to inactivation by activated protein C.

Transient neonatal hyperinsulinemic hypoglycemia and neurological outcome: a case report.

Transient neonatal hyperinsulinemic hypoglycemia (TNHI) is a form of neonatal-onset hyperinsulinism which usually resolves completely in a few days or months. It is secondary to conditions such as maternal diabetes mellitus or intra-uterine growth retardation. Other rare causes of TNHI are perinatal asphyxia and gestational diabetes. Hyperinsulinemic hypoglycemia (HI) is also observed in association with rare metabolic or genetic conditions. It can also occur in newborns without risk factors. TNHI is usually a transient phenomenon. However, some newborns can have prolonged HI that requires treatment with diazoxide, persists for several months and then resolves spontaneously. Neonatal hyperinsulinemic hypoglycemia must be promptly and correctly diagnosed and treated in order to avoid neurological consequences. We describe a case of transient neonatal hyperinsulinemic hypoglycemia in a full-term born without perinatal complications and appropriate for gestational age with an unfavourable neurological outcome.

[Markers of brain injury in non-invasive biological fluids]. / Markers of brain injury in non-invasive biological fluids.

Hypoxia-ischemia (H-I) constitutes the main phenomenon responsible for brain-blood barrier permeability modifications leading to cerebral vascular autoregulation loss in newborns. Hypotension, cerebral ischemia, and reperfusion are the main events involved in vascular auto-regulation loss leading to cell death and tissue damage. Reperfusion could be critical since organ damage, particularly of the brain, may be amplified during this period. An exaggerated activation of vasoactive agents, of calcium mediated effects could be responsible for reperfusion injury (R-I), which, in turns, leads to cerebral hemorrhage and damage. These phenomena represent a common repertoire in newborns complicated by perinatal acute or chronic hypoxia treated by risky procedures such as mechanical ventilation, nitric oxide supplementation, brain cooling, and extracorporeal membrane oxygenation (ECMO). Despite accurate monitoring, the post-insult period is crucial, as clinical symptoms and standard monitoring parameters may be silent at a time when brain damage is already occurring and the therapeutic window for pharmacological intervention is limited. Therefore, the measurement of circulating biochemical markers of brain damage, such as vasoactive agents and nervous tissue peptides is eagerly awaited in clinical practice to detect high risk newborns. The present article is aimed at investigating the role of dosage biochemical markers in non-invasive biological fluids such as S100B, a calcium binding protein, activin A, a protein expressed in Central nervous System (CNS).

A global optimization strategy for predicting alpha-helical protein tertiary structure.

We present a global optimization strategy that incorporates predicted restraints in both a local optimization context and as directives for global optimization approaches, to predict protein tertiary structure for alpha-helical proteins. Specifically, neural networks are used to predict the secondary structure of a protein, restraints are defined as manifestations of the network with a predicted secondary structure and the secondary structure is formed using local minimizations on a protein energy surface, in the presence of the restraints. Those residues predicted to be coil, by the network, define a conformational sub-space that is subject to optimization using a global approach known as stochastic perturbation that has been found to be effective for Lennard-Jones clusters and homo-polypeptides. Our energy surface is an all-atom 'gas phase' molecular mechanics force field, that is combined with a new solvation energy function that penalizes hydrophobic group exposure. This energy function gives the crystal structure of four different alpha-helical proteins as the lowest energy structure relative to other conformations, with correct secondary structure but incorrect tertiary structure. We demonstrate this global optimization strategy by determining the tertiary structure of the A-chain of the alpha-helical protein, uteroglobin and of a four-helix bundle, DNA binding protein.