PubMed Health⌕ Search

Biomedical subjects

C Dani

Publications and source records attributed to C Dani.

At least 37 records · Page 2Linked to original sources
PubMed2001

Emergence during development of the white-adipocyte cell phenotype is independent of the brown-adipocyte cell phenotype.

In mammals, two types of adipose tissue are present, brown and white. They develop sequentially, as brown fat occurs during late gestation whereas white fat grows mainly after birth. However, both tissues have been shown to have great plasticity. Thus an apparent transformation of brown fat into white fat takes place during post-natal development. This observation raises questions about a possible conversion of brown into white adipocytes during development, although indirect data argue against this hypothesis. To investigate such questions in vivo, we generated two types of transgenic line. The first carried a transgene expressing Cre recombinase specifically in brown adipocytes under the control of the rat UCP1 promoter. The second corresponded to an inactive lacZ gene under the control of the human cytomegalovirus promoter. This dormant gene is inducible by Cre because it contains a Stop sequence between two loxP sequences, separating the promoter from the coding sequence. Adipose tissues of progeny derived by crossing independent lines established from both constructs were investigated. LacZ mRNA corresponding to the activated reporter gene was easily detected in brown fat and not typically in white fat, even by reverse transcriptase PCR experiments. These data represent the first direct experimental proof that, during normal development, most white adipocytes do not derive from brown adipocytes.

Adipocytes↗
PubMed2001

Randomised controlled trial of the effect of cisapride on the pyloric muscle in preterm infants.

UNLABELLED: In this study we determined the effects of cisapride on the pyloric muscle in preterm infants. To perform a randomised, double blind, placebo controlled study, two groups each of 16 preterm newborns were given either cisapride (0.2 mg/kg every 8 h) or a placebo for at least 7 days. Infants were studied first on the day when treatment with cisapride or placebo was to be initiated (time 0), and then after 3 (time 1) and 7 days (time 2). In each group, the following parameters were studied by ultrasonography: cross-sectional diameter of the entire pylorus, muscle thickness, and length of the pyloric canal. Also, the mean daily total gastric aspirate volume was studied for the entire week of the study. At time 0, we observed no significant differences between the two groups with respect to diameter, muscle thickness and length of the pyloric muscle. At time 1 and time 2, both diameter and muscle thickness were significantly greater in the cisapride group than in the placebo group. Furthermore, the length of the pyloric canal was significantly greater in the cisapride group than in placebo group at time 2, though not so at time 1. For the entire week of the study, we found a significantly larger mean daily total gastric aspirate volume in the group of infants treated with cisapride compared to the placebo treated group. CONCLUSION: Cisapride significantly affects all of the main measurements of the pyloric muscle and causes a significantly larger amount of daily total gastric aspirate volume. Its use to promote feeding intolerance in preterm newborns cannot be recommended.

Analysis of Variance↗
PubMed2001

The role of blood transfusions and iron intake on retinopathy of prematurity.

BACKGROUND: The role of blood transfusions and iron intake in the pathogenesis or retinopathy of prematurity (ROP) is controversial. AIM: To evaluate the influence of packed red cell (PRC) transfusions and iron intake on ROP incidence. STUDY DESIGN: Prospective observational study. SUBJECTS: Forty-five preterm infants with birthweight <1250 g were studied. After ophthalmological study, they were divided into group A (n=24) that included newborns without ROP, and group B (n=21) that included newborns with ROP. RESULTS: Logistic regression analysis demonstrated that gestational age (OR 0.61; 95% C.I. 0.41-0.90), transfusion volume during the first week (OR 1.16; 95% C.I. 1.03-1.3) and during the first 2 months of life (OR 2.93; 95% C.I. 1.52-5.62), and iron intake during the first week of life (OR 1.15; C.I. 1.01-1.32) and during the first 2 months of life (OR 2.93; 95% C.I. 1.52-5.62) were associated with the development of ROP. CONCLUSION: Our study showed that gestational age, blood transfusion volume and iron load by transfusions are associated with the risk of occurrence of ROP in infants with a birthweight of less than 1250 g.

Erythropoietin↗
PubMed2001

Impaired ossification in mice lacking the transcription factor Sp3.

Sp3 is a ubiquitously expressed member of the Sp family of transcription factors. Recently, the mouse Sp3 gene has been disrupted by homologous recombination. Sp3 null mice die immediately after birth due to respiratory failure. In addition, these mice show a pronounced defect in late tooth formation. Here we show that Sp3 is also required for proper skeletal ossification. Both endochondral and intramembranous ossification are impaired in E18.5 Sp3-/- embryos. The delay in ossification is reflected by reduced expression of the osteoblast-specific marker gene osteocalcin. The transcription factor - core binding factor 1 (Cbfa1)--that is essential for bone formation, however, is expressed at normal levels. In vitro differentiation studies using Sp3-/- ES cells further support the conclusion that Sp3 is needed for correct bone formation. The capacity of Sp3-/- cells to undergo osteogenic differentiation in vitro is reduced and osteocalcin expression is significantly diminished. Our studies establish Sp3 as an essential transcription factor for late bone development.

Animals↗
PubMed2001

Influence of maternal magnesium sulphate and ritodrine treatment on cerebral blood flow velocity of the preterm newborn.

BACKGROUND: To evaluate the effect of antenatal tocolytic administration of magnesium sulphate and ritodrine on the cerebral blood flow velocity and on the cerebral vascular resistance of preterm newborns in the first hours of life. METHODS: Cerebral blood flow velocity, resistance index and relative vascular resistance were studied in 27 preterm infants (<34 weeks gestation) with antenatal exposure to maternal magnesium sulphate treatment and in 27 preterm infants (<34 weeks gestation) with antenatal exposure to maternal ritodrine treatment. Both antenatal magnesium sulphate or ritodrine were used for tocolysis. Cerebral blood flow was measured, using Doppler ultrasonography, in the anterior cerebral artery, in the left middle cerebral artery and in the right middle cerebral artery. RESULTS: We did not find any significant difference in the blood flow velocity, resistance index or relative vascular resistance in the three cerebral arteries between the two treatment groups. CONCLUSIONS: Our study shows that maternal antenatal administration of magnesium sulphate to delay preterm delivery, compared to antenatal administration of ritodrine, does not induce any significant differences either in cerebral blood flow velocity or in cerebral vascular resistance of preterm infants in the first hours of life.

Blood Flow Velocity↗
PubMed2001

Fiberoptic and conventional phototherapy effects on the skin of premature infants.

To evaluate the effects of conventional phototherapy and fiberoptic phototherapy on trans-epidermal water loss in preterm infants with and without skin ointment application, 20 infants were randomly assigned to receive conventional or fiberoptic phototherapy for non-hemolytic hyperbilirubinemia. After conventional phototherapy, there were no significant differences in trans-epidermal water loss between ointment-treated and untreated areas. After fiberoptic phototherapy, trans-epidermal water loss significantly increased from ointment-treated and untreated areas, but the increase was less in treated areas.

Analysis of Variance↗
PubMed2001

Prevention of bilirubin encephalopathy.

Prevention of bilirubin encephalopathy is based on the detection of infants at risk of developing a significant hyperbilirubinemia. This task can be accomplished by performing a simple umbilical cord blood test, such as blood group, Rh, Coombs' test and glucose-6-phosphate dehydrogenase, in order to detect hemolytic diseases. In preterm infants, the prevention of hyperbilirubinemia with phototherapy is a relatively simple task, since these infants are cared for in hospital. Early hospital discharge of full-term neonates represents a major concern. The management of neonatal jaundice requires that therapy begins when total serum bilirubin levels are significantly below the levels at which kernicterus is considered an immediate threat. Unfortunately, determination of serum bilirubin is a painful procedure, and is not very accurate since there is a high variability in laboratory measurements. The accuracy and precision of a new transcutaneous bilirubin measurement, comparable to the standard of care laboratory test, makes the daily evaluation of transcutaneous bilirubin measurement a useful tool in distinguishing physiological from nonphysiological hyperbilirubinemia, and determining the bilirubin increment in the first days of life. Full-term neonates who lose a significant amount of weight are especially at risk of significant hyperbilirubinemia and must be treated with ad libitum feeding and intensive phototherapy.

Bilirubin↗
PubMed2001

Activation of extracellular signal-regulated kinases and CREB/ATF-1 mediate the expression of CCAAT/enhancer binding proteins beta and -delta in preadipocytes.

The essential role of CCAAT/enhancer binding proteins (C/EBPs) beta and delta for adipocyte differentiation has been clearly established. In preadipocytes, their expression is up-regulated by the activation of leukemia inhibitory factor receptor (LIF-R) and prostacyclin receptor (IP-R) via the extracellular signal-regulated kinase (ERK) pathway and cAMP production, respectively. However, the molecular mechanisms by which LIF and prostacyclin-induced signals are propagated to the nucleus and the transcription factors mediating ERK and cAMP-induced C/EBP gene expression were unknown. Here we report that both pathways share cAMP responsive element binding protein/activation transcription factor 1 (CREB/ATF-1) as common downstream effectors. LIF-R and IP-R activation induced binding of CREB and/or ATF-1 to C/EBP promoters and CREB-dependent transcription. Expression of dominant negative forms of CREB dramatically reduced the LIF- and prostacyclin-stimulated C/EBP beta and C/EBP delta expression. Upon stimulation of the IP-R, the ERK pathway was activated in a PKA-dependent manner. ERK activation by the PKA pathway was not required for CREB/ATF-1 phosphorylation but rather was necessary for CREB-dependent up-regulation of C/EBPs expression. Our findings suggest that ERK activation is required for CREB transcriptional activity, possibly by recruitment of a coactivator.

Activating Transcription Factor 1↗
PubMed2001

Liquid ventilation in an infant with persistent interstitial pulmonary emphysema.

We present the case of a full term infant affected by diffuse persistent interstitial pulmonary emphysema (PIPE), who was treated with partial liquid ventilation (PLV) after the failure of conventional management. PIPE is a lethal chronic lung disease of unclear pathogenesis. Clinical history, radiological and histological findings confirmed the diagnosis in our patient. PLV applied for 48 hours resulted in a significant improvement in the infant's respiratory function and was not associated with adverse effects. We concluded that PLV could be effective in prolonging the survival of infants with PIPE; its application represents an effective form of respiratory support in infants with chronic lung disease.

Adult↗
PubMed2001

Is breastfeeding really favoring early neonatal jaundice?

OBJECTIVE: The purpose of this study was to evaluate the development of significant hyperbilirubinemia in a large unselected newborn population in a metropolitan area with particular attention to the relationship between type of feeding and incidence of neonatal jaundice in the first week of life. STUDY DESIGN: A population of 2174 infants with gestational age >/=37 weeks was prospectively investigated during the first days of life. Total serum bilirubin determinations were performed on infants with jaundice. The following variables were studied: type of feeding, method of delivery, weight loss after birth in relationship to the type of feeding, and maternal and neonatal risk factors for jaundice. Statistical analyses were performed using the z test for parametric variables and the t test for nonparametric variables. In addition, the multiple logistic regression allows for the estimation of the role of the individual characteristics in the development of hyperbilirubinemia. Data concerning serum bilirubin peak distribution in jaundiced newborns were analyzed using a single and a double Gaussian best fit at least squares. The t test was performed to compare 2 values (high and low) of the serum bilirubin peak in breastfed and supplementary-fed infants with those in bottle-fed infants. RESULTS: The maximal serum bilirubin concentration exceeded 12.9 mg/dL (221 micromol/L) in 112 infants (5.1%). The study demonstrated a statistically significant positive correlation between patients with a total serum bilirubin concentration >12.9 mg/dL (221 micromol/L) and supplementary feeding; oppositely, breastfed neonates did not present a higher frequency of significant hyperbilirubinemia in the first days of life. However, best Gaussian fitting of our data suggests that a small subpopulation of breastfed infants have a higher serum bilirubin peak than do bottle-fed infants. Newborns with significant hyperbilirubinemia underwent a greater weight loss after birth compared with the overall studied population, and infants given mixed feeding lost more weight than breastfed and formula-fed newborns, indicating that formula has been administered in neonates who had a weight loss beyond a predetermined percentage of birth weight. Significant hyperbilirubinemia was also strongly associated with delivery by vacuum extractor, some perinatal complications (cephalohematoma, positive Coombs' test, and blood group systems of A, AB, B, and O [ABO] incompatibility) and Asian origin. Multiple logistic regression analysis shows that supplementary feeding, weight loss percentage, ABO incompatibility, and vacuum extraction significantly increase the risk of jaundice, while only cesarean section decreases the risk. CONCLUSION: The present study confirms the important role of fasting in the pathogenesis of neonatal hyperbilirubinemia, although breastfeeding per se does not seem related to the increased frequency of neonatal jaundice but to the higher bilirubin level in a very small subpopulation of infants with jaundice. In fact, in the breastfed infants, there is a small subpopulation with higher serum bilirubin levels. These infants, when starved and/or dehydrated, could probably be at high risk of bilirubin encephalopathy.

Bilirubin↗
PubMed2000

Prostacyclin IP receptor up-regulates the early expression of C/EBPbeta and C/EBPdelta in preadipose cells.

Prostacyclin (PGI(2)) and its stable analogue carbacyclin (cPGI(2)) are known to trigger the protein kinase A pathway after binding to the cell surface IP receptor and to promote or enhance terminal differentiation of adipose precursor cells to adipose cells. The early expression of C/EBPbeta and C/EBPdelta is known to be critical for adipocyte differentiation in vitro as well as in vivo. We report herein that in Ob1771 and 3T3-F442A preadipose cells, activation of the IP receptor by specific agonists (PGI(2), cPGI(2) and BMY 45778) is sufficient to up-regulate rapidly the expression of C/EBPbeta and C/EBPdelta. Cyclic AMP-elevating agents are able to substitute for IP receptor agonists, in agreement with the coupling of IP receptor to adenylate cyclase. Consistent with the fact that PGI(2) is released from preadipose cells and behaves as a paracrine/autocrine effector of adipose cell differentiation, the present results favor a key role of prostacyclin by means of the IP receptor and its intracellular signaling pathway in eliciting the critical early expression of both transcription factors.

3T3 Cells↗
PubMed2000

Prophylaxis of patent ductus arteriosus with ibuprofen in preterm infants.

UNLABELLED: The aim of our study was to evaluate whether the prophylactic use of ibuprofen would reduce the incidence of significant patent ductus arteriosus (PDA) and to confirm the effectiveness of ibuprofen as rescue treatment in closing PDA. Eighty preterm infants with gestational age less than 34 wk with infant respiratory distress syndrome (iRDS) were randomized to receive intravenous ibuprofen lysine (10 mg/kg, followed by 5 mg/kg after 24 and 48 h) either within 24 h of life (group A) or after echocardiographic diagnosis of PDA (group B). To evaluate the severity of RDS in each patient, we calculated the initial and highest values of Oxygenation Index (O.I. = mean airway pressure x FiO2 x 100/PaO2) and Ventilatory Index (V.I. = O.I. x mechanical respiratory rate). Other studied variables were ventilatory support, renal function, biochemical and haematological profiles, frequency of bronchopulmonary dysplasia (BPD), intraventricular haemorrhage (IVH), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). On the 3rd day of life, 8% (3/40) of patients of group A and 53% of patients (21/40) of group B (p < 0.0001) developed a significant PDA. Between patients of group B who presented PDA at 3 d of life 90% (19/21) had a closure of ductus arteriosus after ibuprofen treatment. Initial and highest values of O.I. and V.I. were similar in both groups A and B. No significant differences between the groups were observed in regard to respiratory support, renal function and frequency of BPD, IVH, NEC and ROP. Ibuprofen was not associated with adverse effects. CONCLUSION: Prophylactic treatment with ibuprofen reduces PDA occurrence in preterm infants with iRDS at 3 d of life in comparison with rescue treatment, but both modes are effective in closing the ductus without significant adverse effects.

Age Factors↗
PubMed2000

Brain hemodynamic changes in preterm infants after maintenance dose caffeine and aminophylline treatment.

OBJECTIVE: To investigate the acute effects of low-dose caffeine and aminophylline on cerebral blood flow in preterm infants, using both near-infrared spectroscopy (NIRS) and cerebral Doppler ultrasonography. METHODS: Preterm infants with a gestational age of <32 weeks and birth weight of <1,500 g were randomized to receive either caffeine or aminophylline treatment for apnea of prematurity. The study period went from 30 min before to 60 min after the administration of the maintenance dose of pure caffeine (2.5 mg/kg once a day) or aminophylline (1.25 mg/kg twice a day). NIRS was used to measure changes in oxygenated hemoglobin (O(2)Hb), deoxygenated hemoglobin (HHb), oxidized-reduced cytochrome aa3 (CtOx), and mean cerebral oxygen saturation (SmO(2) = O(2)Hb/total Hb). Changes in cerebral blood volume (DeltaCBV) after caffeine or aminophylline administration were calculated. Cerebral blood flow velocity (CBV) in the pericallosal artery was evaluated by cerebral Doppler ultrasounds. RESULTS: Data collected by NIRS and cerebral Doppler ultrasounds did not show significant differences before and after caffeine treatment. We observed a significant increase in O(2)Hb and HHb concentration and in CBV at 30 min after the infusion of aminophylline, which tended to return to baseline at the end of the study period. CONCLUSION: Caffeine does not significantly affect brain hemodynamics, while aminophylline induces a significant transient increase in O(2)Hb and HHb concentration and CBV.

Aminophylline↗
PubMed2000

[Prophylaxis of group B beta-hemolytic streptococcal infections].

Group B streptococcus is a possible cause of chorioamnionitis, endometritis and urinary tract infections in pregnant woman. Maternal risk factors and the vertical transmission of GBS and neonatal GBS infection occur through the following fever during labor, the rupturing of membranes more than 18 hours before delivery, prematurity and chorioamnionitis. GBS can induce early-onset neonatal disease (sepsis, meningitis or pneumonia) during the first week of life and late-onset neonatal infection (leptomeningitis) within the first 12 weeks of life. Numerous strategies for preventing neonatal group B streptococcal infection were investigated: 1) the treatment of GBS-colonized women during the third trimester of pregnancy did not prove to be effective because it does not reduce maternal colonizzation rates at delivery; 2) the neonatal universal post-partum prophylaxis with penicillin G was ineffective and increased neonatal mortality due to penicillin-resistant bacterial infection; 3) the intrapartum maternal chemoprophylaxis with penicillin G or ampicillin in GBS-colonized women, in women with risk factors, or in women with both GBS colonization and risk factors. The latter strategy proved to be the most effective because it reduces the risk of early-onset GBS infection by 75% and 95% when associated with post-neonatal prophylaxis. To date, there are no guidelines on the management of the asymptomatic neonate whose mothers have been treated with chemopropylaxis intra-partum.

Humans↗
PubMed1999

Role of pathways for signal transducers and activators of transcription, and mitogen-activated protein kinase in adipocyte differentiation.

Members of the signal transducer and activator of transcription (STAT) family and the mitogen-activated protein kinase (MAPK) cascade play a major role in the regulation of cell growth and differentiation. This review concentrates on the role played by these pathways in the development of adipose cells. STATs are activated by both positive and negative modulators of adipocyte differentiation leading to the hypothesis that the STAT pathway may function in adipogenesis. The role of the p42/p44 MAPK pathway in adipocyte differentiation has recently been the subject of contradictory reports. Several molecular mechanisms are proposed to explain the opposing effects of MAPK activation in the programme of adipose cell differentiation.

Adipocytes↗
PubMed1999

Leukemia inhibitory factor and its receptor promote adipocyte differentiation via the mitogen-activated protein kinase cascade.

Extracellular factors and intracellular signaling pathways involved in early events of adipocyte differentiation are poorly defined. It is shown herein that expression of leukemia inhibitory factor (LIF) and LIF receptor is developmentally regulated during adipocyte differentiation. Preadipocytes secrete bioactive LIF, and an antagonist of LIF receptor inhibits adipogenesis. Genetically modified embryonic stem (ES) cells combined with culture conditions to commit stem cells into the adipocyte lineage were used to examine the requirement of LIF receptor during in vitro development of adipose cells. The capacity of embryoid bodies derived from lifr(-/-) ES cells to undergo adipocyte differentiation is dramatically reduced. LIF addition stimulates adipocyte differentiation of Ob1771 and 3T3-F442A preadipocytes and that of peroxisome proliferator-activated receptor gamma2 ligand-treated mouse embryonic fibroblasts. Expression of the early adipogenic transcription factors C/EBPbeta and C/EBPdelta is rapidly stimulated following exposure of preadipose cells to LIF. The selective inhibitors of mitogen-activated protein kinase kinase, i.e. PD98059 and U0126, inhibit LIF-induced C/EBP gene expression and prevent adipocyte differentiation induced by LIF. These results are in favor of a model that implicates stimulation of LIF receptor in the commitment of preadipocytes to undergo terminal differentiation by controlling the early expression of C/EBPbeta and C/EBPdelta genes via the mitogen-activated protein kinase cascade.

Adipocytes↗