178,121 research outputs found
Mario Bracci e il suo archivio
No full textIl fascicolo 2 dell'annata 127 (2015) di "Studi senesi" raccoglie gli atti del seminario "Mario Bracci e il suo archivio" (Siena, Aula magna storica, 16 aprile 2015). Comprende saggi di S. Fruzzetti, S. Moscadelli, G. Cianferotti, F. Colao, E. Bindi, L. Nuti e i testi degli interventi nella tavola rotonda finale di M. Barni, G. Grottanelli de' Santi, R. Bracci, G. Catoni
Chorioamnionitis: a risk factor for fetal and neonatal morbidity
No full textDespite widespread use of drugs to arrest preterm labor, there has been no decrease in the numbers of low-birth-weight or preterm infants in the last 20 years. Evidence from many sources links preterm birth to symptomatic and subclinical infections. Recently, an increasing body of evidence has suggested that not only is subclinical infection responsible for preterm birth but also for many serious neonatal sequelae, including periventricular leukomalacia, cerebral palsy, respiratory distress and even bronchopulmonary dysplasia and necrotizing enterocolitis. Proxies of intrauterine infection include clinical chorioamnionitis, histological chorioamnionitis and intraamniotic increase in cytokines, which have been found to be associated with acute neonatal morbidity and mortality and, at least to some degree, with neurological impairment, chronic lung disease and thymus involution in the preterm infant. The infectious/inflammatory mechanisms involved are not fully understood, and the types of microbes and genetic features of host adaptive and innate immune responses need to be better characterized
Studio e realizzazione di un modello sperimentale di robot planare a due bracci
No full textPer riprodurre in laboratorio alcune delle più comuni cause di imprecisione è stato progettato e realizzato un modello sperimentale di robot planare a due bracci. La caratteristica principale del modello è di consentire con semplici manovre la sostituzione dei bracci, dei giunti, dei riduttori e della trasmissione. Sono state eseguite prove sperimentali che hanno dimostrato l’attitudine del modello a rendere visibili e misurabili gli effetti conseguenti a diverse fonti meccaniche di errore
Oxidant injury in neonatal erythrocytes during the perinatal period
No full textIt has been known for many decades that oxidative stress leads to oxidation of hemoglobin and damage to the erythrocyte membrane. More recently, the factors involved in denaturating of membrane proteins and lipid peroxidation have been investigated in detail, as well as the mechanism of reactive oxygen species formation in red cells. Oxidative stress depletes adenosine triphosphate (ATP) and adenine nucleotides, whereas adenosine monophosphate (AMP) deaminase seems to depress energy metabolism by blocking the salvage pathway of purine nucleotides. Depletion of ATP and activation of AMP deaminase are related to calcium ion concentrations. Denaturating of membrane proteins generally precedes lipid peroxidation and consequent phagocytosis due to caspase activation. Extensive investigations demonstrated the key role of oxidative stress and iron release in a reactive form causing membrane protein damage via the Fenton reaction and hydroxyl radical production. In the absence of efficient protection by antioxidant factors and other molecules such as flavonoids, oxidative stress is responsible for the release of iron in reactive form, predisposing red cells to hemolysis through the formation of senescence antigen. Other well-known sources of oxidative stress in red cells are free radical production outside the red cell by activated phagocytes, endothelial metabolism, hyperoxia, ischemia-reperfusion and the arachidonic acid cascade. CONCLUSION: The recent insight into the mechanism of oxidative injury of red cells and evidence of relationships between erythrocyte oxidative stress and hypoxia suggest that increased hemolysis is induced by severe hypoxia and acidosis in the fetus as well as the newborn
The Timing of Neonatal Brain Damage
No full textAlthough neonatal morbidity and mortality are less than in the past, the risk of pre-natal and neonatal brain damage has not been eliminated. In order to optimize pre-natal, perinatal and neonatal care, it is necessary to detect factors responsible for brain damage and obtain information about their timing. Knowledge of the timing of asphyxia, infections and circulatory abnormalities would enable obstetricians and neonatologists to improve prevention in pre-term and full-term neonates. Cardiotocography has been criticized as being too indirect a sign of fetal condition and as having various technical pitfalls, though its reliability seems to be improved by association with pulse oximetry, fetal blood pH and electrocardiography. Neuroimaging is particularly useful to determine the timing of hypoxic-ischemic brain damage. Cranial ultrasound has been used to determine the type and evolution of brain damage. Magnetic resonance has also been used to detect antenatal, perinatal and neonatal abnormalities and timing on the basis of standardized assessment of brain maturation. Advances in the interpretation of neonatal electroencephalograms have also made this technique useful for determining the timing of brain lesions. Nucleated red blood cell count in cord blood has been recognized as an important indication of the timing of pre-natal hypoxia, and even abnormal lymphocyte and thrombocyte counts may be used to establish pre-natal asphyxia. Cord blood pH and base excess are well-known markers of fetal hypoxia, but are best combined with heart rate and blood pressure. Other markers of fetal and neonatal hypoxia useful for determining the timing of brain damage are assays of lactate and markers of oxidative stress in cord blood and neonatal blood. Cytokines in blood and amniotic fluid may indicate chorioamnionitis or post-natal infections. The determination of activin and protein S100 has also been proposed. Obstetricians and neonatologists can therefore now rely on various methods for monitoring the risk of brain damage in the antenatal and post-natal periods
Total hydroperoxide and advanced oxidation protein products in preterm hypoxic babies
No full textPrevious studies have shown that plasma lipoproteins are a common target of free radical-induced oxidative stress in hypoxic newborn infants. In contrast to lipids, the reaction of proteins with various oxidants during hypoxia has not been extensively studied. We tested the hypothesis that tissue hypoxia results in increased production of protein oxidation in cord blood of preterm newborns. Heparinized blood samples of 39 hypoxic and 16 control preterm newborns were obtained from the umbilical vein, after cord clamping immediately after delivery. Plasma levels of total hydroperoxide (TH), advanced oxidation protein products (AOPP), hypoxanthine (Hx), xanthine (Xa), and uric acid (UA) were measured. Higher Hx, Xa, UA, TH, and AOPP levels were found in hypoxic newborn infants than in controls. Statistically significant correlations were observed between: TH and Hx (r = 0.54, p = 0.003, n = 28), AOPP and Hx (r = 0.64, p = 0.0001, n = 27), and TH and AOPP plasma levels (r = 0.50, p = 0.02, n = 21). In summary, TH, AOPP, Hx, Xa, and UA production is increased in fetal blood during hypoxia. The more severe the hypoxia, the higher the lipid and protein damage by free radicals
New biomarkers of fetal-neonatal hypoxic stress
No full textThe complex pathophysiological mechanisms underlying perinatal hypoxia make it difficult to define early markers of severe hypoxia-ischemia encephalopathy. However, as progress in the development of neuroprotective therapeutic measures continues, the early identification of neonates at risk of severe hypoxic-ischemic encephalopathy is an important goal for appropriate decision making. Although the timing of perinatal hypoxic brain damage may vary and is sometimes unknown, high levels of non-protein-bound iron and high nucleated red blood cell counts in cord blood indicate an antepartum origin of neurological impairment, because they can occur only as a consequence of a pre-existing asphyxic event. CONCLUSION: The combined assessment of nucleated red blood cells and non-protein-bound iron at birth seems extremely useful for the early identification of newborns at high risk of brain damage. Activin A also seems to be a reliable marker of perinatal hypoxia. Prospective long-term follow-up studies are needed to verify their predictive role
Intrauterine growth restriction : obstetric aspects
No full textThis new textbook wants to offer to neonatologists and pediatricians a modern and complete view of the various problems and aspects of neonatology, currently one of the most complex and advanced fields of pediatrics. The first chapters will be dedicated to the epidemiology of neonatal mortality and morbidity and to the conditions responsible for neonatal risk. A section will be devoted to organizational problems of hospitals and home services for efficient modern neonatal and infant care. Particular attention will be paid to neonatal care, medico-legal questions, examination of newborns and current availability of laboratory facilities and instrumentation for identification of perinatal abnormalities. Neonatal nutritional problems will also be examined, outlining current knowledge of the needs of sick and healthy babies. Conditions jeopardizing fetal health such as diabetes, maternal drug abuse and smoking will be discussed. New advances in neonatal pharmacology will be extensively examined. Various diseases of the neonate involving lungs, heart, gastrointestinal tract, blood, immune system, endocrine system and kidneys will be also expounded in special chapters. Fetal and neonatal infections will be extensively discussed. Fetal and neonatal neurological abnormalities will be discussed by highly specialized authors. There will be chapters on neonatal ophthalmology, dermatology and orthopedics. Each chapter has beeb written by a well recognized international expert in his or her field. As the opinion leader in their field, the Author is responsible for giving the most up-to-date information in terms of what is known, what is still being researched, and what has become evidence based medicine. Underlying causes and mechanisms of neonatal diseases will be presented in an immediate form. The use of summaries, tables, and accurately selected guidelines or recommendations that will accompany the text will supply quick references and instant solutions to the concerned neonatologists during their daily practice.
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