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Biomedical subjects

U Simeoni

Publications and source records attributed to U Simeoni.

At least 19 recordsLinked to original sources
PubMed2005

[Blood product transfusion in the neonatal period].

Newborn infants in intensive care units, especially those born premature, are at particular risk for blood transfusion adverse effects. Aside improvements in the preparation of specific blood products for the neonatal period, such as multiple packed cells preparations from a single donor for multiple transfusions in premature infants, progress has involved prophylaxis of anemia of prematurity as well. Recombinant human erythropoietin has proven to be beneficial with high range evidence. Also, alternative methods have been proposed to compensate for the delay in the effect of rHuEPO, such as delayed clamping of umbilical cord at birth, or autologous placental blood transfusion. However, a better understanding of the indications of blood transfusion and the provision of practice guidelines may justify a re-evaluation of prophylactic strategies for anemia of prematurity.

Anemia↗
PubMed2004

Antioxidant status of neonates exposed in utero to tobacco smoke.

To investigate the influence of maternal smoke exposure on neonatal and maternal antioxidant status, 39 mothers who were active smokers, 14 mothers exposed to environmental tobacco smoke (ETS), 17 controls, and their newborns were included in a prospective, controlled study. Plasma total antioxidant capacity, measured as total radical-trapping antioxidant parameter (TRAP) and ferric reducing antioxidant power (FRAP), and concentrations of specific antioxidants were measured in cord and in maternal blood. A similar, significant increase in ceruloplasmin concentration was observed in neonates born to actively smoking mothers and in those born to ETS exposed mothers. Uric acid and TRAP concentrations were significantly increased in ETS-exposed newborns and their mothers, compared to newborns and mothers from the active smoking and no-exposure groups with a trend towards increased uric acid, TRAP and FRAP concentrations being observed in the active smokers group. Neonatal and maternal antioxidant concentrations correlated significantly, except for ceruloplasmin. Cord blood vitamin A, E and C concentrations were unaffected by smoke exposure. These results show that maternal active smoking as well as ETS exposure significantly affect neonatal and maternal antioxidant status.

Adult↗
PubMed2004

Cushing's syndrome in pregnancy and neonatal hypertrophic obstructive cardiomyopathy.

Cushing's syndrome is rare in pregnancy but can cause spontaneous abortion, stillbirth or premature birth. We report a case of transient hypertrophic obstructive cardiomyopathy in a newborn whose mother had hypercortisolism due to a primary adrenal lesion. There was no family history of hypertrophic obstructive cardiomyopathy. Follow-up revealed complete resolution of the cardiac abnormalities in the infant. Cushing's syndrome in the mother resolved after delivery. Although maternal hypercortisolism seldom results in symptomatic hypercortisolism in the newborn, hypertrophic obstructive cardiomyopathy can occur.

Cardiomyopathy, Hypertrophic↗
PubMed2002

[Neonatal hyperbilirubinemia: myths and realities].

This paper reproduces the introducing talk of the round table conference on current management of neonatal hyperbilirubinemia held during the Journée d'Actualité Lorraine en Néonatologie (JALON 2002, Nancy, october 5th 2002).

Humans↗
PubMed2001

Developmental aspects of parathyroid hormone-related protein biology.

Parathyroid hormone-related protein (PTHrP) has been discovered as a parathyroid hormone (PTH)-like factor responsible for the humoral hypercalcaemia of malignancies. Further studies revealed that PTHrP is ubiquitously expressed, in mature as well as in developing normal tissues from various species. Although not completely understood, the biological roles of PTHrP concern a variety of domains, including calcium phosphorus metabolism and bone mineralization, smooth muscle relaxation, cell growth and differentiation, and embryonic development. As a poly-hormone, PTHrP is now acknowledged to act via the paracrine, autocrine, and even the intracrine pathways. This review focuses on the main developmental features of the biology of PTHrP. During embryonic development, PTHrP is considered to be involved as a growth factor that promotes cell proliferation and delays cell terminal maturation. PTHrP has been shown to intervene in the development of various tissues and organs such as the skeleton, skin, hair follicles, tooth, pancreas, and the kidney. In addition, through its midregion sequence, which is able to promote an active transplacental calcium transport, PTHrP may intervene indirectly in the mineralization of the foetal skeleton. PTHrP has also been shown to be necessary for the normal development of the mammary gland, while huge amounts of PTHrP are found in the human milk. Finally, observations of physiologic, vasodilating effects of PTHrP in the kidney suggest its involvment in the control of renal hemodynamics, especially in the perinatal period.

Animals↗
PubMed2001

[Withholding and withdrawing treatment in the perinatal period: importance of a coherent attitude between gyneco-obstetricians and pediatricians].

According to several recent surveys, 50% of deaths occurring in neonatal intensive care units in France occur subsequent to a medical decision. The French Neonatal Group therefore decided to publish guidelines for practice. These guidelines present: definitions, clinical situations, ethical principles, obligations of the medical and nursing staff, and specific conditions where dilemmas occur. These guidelines focus on the obstetrico-pediatrics relationship.

Attitude of Health Personnel↗
PubMed2001

[Extreme prematurity: the limits of neonatal resuscitation].

How far providing neonatal intensive care to extremely low birth weight infants is appropriate is still a highly controversial issue. Decision making when a poor prognosis has been established may be facilitated by consensus based recommendations and rigorous procedures. In the very majority of situations, the provision of intensive care is advocated at birth a priori. A decision of treatment withholding or withdrawal may eventually be made secondarily, in the case major neurological complications, likely to induce severe long term deficits, are evidenced. In any case, an ethical policy focused on each infant's best interest is justified, while the adoption of a systematic, gestational age or birth weight based restriction of access to intensive care may not be acceptable in most countries. Rigorous criteria must be fulfilled for end of life decision making and procedures. Continuous assistance to the patient and to the parents is key determinant.

Ethics, Medical↗
PubMed1999

[Accidental ingestion of button battery].

Button batteries are easily swallowed by children and may produce severe digestive injuries through two different mechanisms: electrochemical burns when in contact with the digestive mucosa, release of caustic substances when fragmented. Esophageal lesions are especially dangerous, as they can lead to perforation, fistula or secondary stenosis. The risk of mercury intoxication is less worrying since the assimilated fraction of the metal is unlikely to produce clinical effect. Although the large majority of the reported cases of button battery ingestion remained asymptomatic, the potentially lethal outcome justifies a precise diagnostic procedure: any button battery ingestion must be documented with a radiography of the digestive tract. Any battery lodged in the esophagus must be urgently removed by endoscopy. Other locations do not need any removal attempt unless complications: nonetheless a follow-up is necessary to confirm the spontaneous elimination of the battery. Manufacturers, physicians and parents share responsibility for preventing such accidents.

Accident Prevention↗
PubMed1999

[What is new in neonatology?].

Advances in neonatology have been consistent in recent years, both from practical and theoretical points of view. Improved outcome is the result of major developments in neonatal intensive care, but also of the improved organization of perinatal care. Recent concepts on the inflammatory mechanisms of preterm labor and periventricular leukomalacia are opening a new area for preventive intervention. The observed association between the occurrence of diseases such as hypertension in adulthood and intrauterine growth retardation offers a particular insight into the long term programming of physiologic regulations in the fetus. At the bedside, advances in neonatal intensive care have been significant, especially in treating neonatal respiratory failure. This review will focus on recent developments in premature anemia, and in fluid-electrolyte therapy in very low infant birth weights, as both topics have been less frequently reviewed in the pediatric literature. Finally, ethical issues have deserved considerable attention, such as therapeutic intervention in extremely low birth weight infants, decision-taking, and practices in withholding or withdrawing therapy during neonatal intensive care, along with the need for long term follow up and assistance to the patients and their families.

Adult↗
PubMed1997

Postnatal development of vascular resistance of the rabbit isolated perfused kidney: modulation by nitric oxide and angiotensin II.

Studies were performed on isolated perfused kidneys (IPK) from postnatal developing rabbits to ask 1) whether the high renal vascular resistance (RVR) at birth involves intrinsic renal mechanisms, 2) whether nitric oxide (NO) release is involved in the modulation of renal vascular tone, and 3) whether NO modulates exogenous angiotensin II (AII)-induced vasoconstrictions. Kidneys isolated from 1-wk-old (during nephrogenesis), 3-wk-old (after nephrogenesis), and 6-wk-old rabbits were perfused in the presence of 10(-5) M indomethacin. RVR decreased with age from 12.7 +/- 0.6 at 1 wk to 10.1 +/- 0.5 mm Hg min g mL-1 at 6 wk. N omega-Nitro-L-arginine methyl ester (L-NAME, 10(-4) M) comparably increased RVR by about 30% at 1, 3, and 6 wk. The vasoconstrictions induced by 10(-8) M AII increased basal pressure from 28% at 1 wk to 78% at 6 wk and were potentiated by L-NAME by about 100%. In contrast, the vasoconstrictions induced by 10(-10) M AII decreased from 8% at 1 wk to 0% at 6 wk and were potentiated by L-NAME by about 250% at 1 and 3 wk. We conclude that during postnatal development: 1) RVR in IPK decreases in absence of AII and extrarenal influences, suggesting that high RVR at birth involves intrinsic mechanisms, 2) L-Arg/NO modulates basal tonus in developing IPK, and, 3) renal vasoconstrictor responses to exogenous AII are buffered by NO at early postnatal stages and follow an AII concentration-dependent developmental pattern. A specific neonatal high affinity AII/NO interaction disappearing after nephrogenesis completion precedes a low affinity AII/NO interaction, which progressively increases toward adult ages. These findings are in favor of a specific involvement of AII-NO interactions in the control of developing renal hemodynamics.

Age Factors↗
PubMed1996

Evaluation of interleukin-6 and soluble receptors of tumor necrosis factor for early diagnosis of neonatal infection.

OBJECTIVE: To evaluate plasma levels of interleukin-6 (IL-6) and soluble tumor necrosis factor receptors (sTNF-R) 55 and 75 in neonates as a contribution to the early diagnosis of infection. STUDY DESIGN: We prospectively measured IL-6 and sTNF-R 55 and sTNF-R 75 plasma levels in 157 newborn infants admitted to our regional neonatal center in a 3-month period and in cord blood of 131 newborn infants delivered in our obstetrics unit. C-reactive protein was sequentially determined after admission. Newborn infants were classified into four groups: group 0, not infected; group 1, possibly infected; group 2a, infected (culture positive), and group 2b, probably infected (culture negative). We looked for the optimal cutoff point of these parameters, using the receiver operating characteristics (ROC) curve. RESULTS: IL-6 levels were significantly higher in group 2 (n = 11; median level, 250 pg/ml; range, 0 to 81,000), group 2b (n = 25; median level, 750 pg/ml; range, 0 to 180,000), and group 1 (n = 35; median level, 160 pg/ml; range 0 to 10,000), in comparison with group 0 (n = 217; median level, 0 pg/ml; range, 0 to 3400). A cutoff value of 100 pg/ml or greater obtained by the ROC method gives a sensitivity of 83.3% and a specificity of 90.3%. For inborn infants (n = 220) sampled at birth, sensitivity is 100% and specificity 92.3%. This high sensitivity persists until the twelfth hour of life. The sTNF-R 55 levels are significantly higher in group 2a (median, 12.0 ng/ml; range, 3.2 to 24.4). In group 2b (median, 7.0 ng/ml; range, 3.0 to 25.2), and in group 1 (median, 7.0 ng/ml; range, 2.5 to 18.9) than in group 0 (median, 3.9 ng/ml; range, 1.5 to 15.0), and with a cutoff value of 6 ng/ml, sensitivity is 75% and specificity 69%. The sTNF-R 75 levels are significantly higher in group 2a (median, 17.0 ng/ml; range, 7.2 to 48.8). In group 2b (median, 11.2 ng/ ml; range, (2.0 to 31.3), and in group 1 (median, 10.6 ng/ml; range, 2.0 to 33.0); than in group 0 (median, 7.0 ng/ml; range, 1 to 23.0). With a cutoff value of 9 ng/ ml, sensitivity is 80% and specificity 67%. Sensitivity of C-reactive protein is low initially but improves with time. Combining IL-6 with C-reactive protein provides the possibility of identifying the majority of infected infants in the postnatal period. CONCLUSION: A plasma IL-6 level of 100 pg/ml or greater, obtained before the twelfth hour of life, appears to be an ideal marker for detecting early-onset neonatal infection with a high degree of sensitivity and specificity. After the twelfth hour, the combined determination of IL-6 and C-reactive protein may be equally useful. The sTNF-R levels appear to be less useful in the early diagnosis of infection because of their smaller magnitude of variation.

Antigens, CD↗
PubMed1995

Auxiliary liver transplantation for fulminant and subfulminant hepatic failure.

We report the first series of 9 auxiliary liver transplantations performed as a bridge to recovery in 8 patients with fulminant and subfulminant hepatic failure. Hepatic failure was due to hepatitis A virus (n = 3), hepatitis B virus (n = 1), hepatotoxic drugs (n = 2), autoimmune disease (n = 1), or it was of unknown origin (n = 1). The donor liver was reduced to a left lobe (n = 2), a left liver (n = 4), or a right liver (n = 3), and was implanted in an orthotopic position beside the native liver after it was resected by a left or a right hepatectomy. Conventional immunosuppression was used to prevent rejection. Six patients regained normal consciousness within 2 weeks, without any sequelae. Two patients had persisting encephalopathy due to graft initial dysfunction, one of whom showed portal vein thrombosis, which was successfully cleared. The other one showed hepatic vein stenosis and was retransplanted at day 15. Five of eight patients had to be reoperated because of a surgical complication. Five patients showed rapid regeneration of their native liver, but one died at day 45 from severe herpes virus broncholitis. The auxiliary grafts were removed (n = 3) or left to atrophy by tapering immunosuppression (n = 1). One patient developed cirrhosis of the native liver and died of infectious complications at day 42. The native livers of the two remaining patients are still atrophic, one at 4 months and one at 1 month posttransplant. Finally, 6 of 8 patients are alive with a follow-up of 1 to 17 months. Four of them have permanently stopped their immunosuppressive therapy. Our experience demonstrates that auxiliary orthotopic liver transplantation (1) is feasible in children and adults, using either a left or a right liver graft, (2) is efficient in providing adequate liver function, and (3) gives a real chance to the native liver to regenerate, offering these patients a future free of immunosuppression.

Adolescent↗
PubMed1994

Involvement of nitric oxide in the vasodilatory response to parathyroid hormone-related peptide in the isolated rabbit kidney.

1. The present study was designed to explore the role of NO derived from L-arginine in the vasodilatory response to synthetic human parathyroid hormone-related peptide-(1-34) in the isolated rabbit kidney perfused in the presence of indomethacin (10 mumol/l) and preconstricted with noradrenaline (7.2 nmol/min). 2. Under control conditions, bolus administrations of acetylcholine (10 mumol/l), an NO-dependent renal vasodilator, verapamil (0.1 mmol/l), an NO-independent renal vasodilator, and parathyroid hormone-related peptide (87 nmol/l) decreased the preconstriction pressure, by 31%, 71% and 43%, respectively. 3. Bolus administration of 100 mumol/l NG-nitro-L-arginine-methyl ester caused a 20% increment in the perfusion pressure of the noradrenaline-preconstricted kidney. NG-nitro-L-arginine methyl ester inhibited the vasodilatory effect of acetylcholine and parathyroid hormone-related peptide, by 68% and 44%, respectively, but did not alter the verapamil-induced vasodilatation. 4. Unlike L-arginine, the bolus administration of 1 mumol/l of a mono-substituted L-arginine derivative, N-alpha-benzoyl-L-arginine ethyl ester, durable decreased the noradrenaline/NG-nitro-L-arginine methyl ester-induced preconstriction by 57%. 5. Both L-arginine and N-alpha-benzoyl-L-arginine ethyl ester effectively reversed the inhibition induced by NG-nitro-L-arginine methyl ester on the vasodilatation elicited by acetylcholine and parathyroid hormone-related peptide. 6. In conclusion, the formation of NO from L-arginine contributes a substantial part to the vasodilatory action of parathyroid hormone-related peptide. Therefore, parathyroid hormone-related peptide appears to have a place among the renal haemodynamically active substances, whose vasodilatory actions are tuned by NO.

Acetylcholine↗