Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
N Engl J Med ; 382(3): 233-243, 2020 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-31940698

RESUMEN

BACKGROUND: High-dose erythropoietin has been shown to have a neuroprotective effect in preclinical models of neonatal brain injury, and phase 2 trials have suggested possible efficacy; however, the benefits and safety of this therapy in extremely preterm infants have not been established. METHODS: In this multicenter, randomized, double-blind trial of high-dose erythropoietin, we assigned 941 infants who were born at 24 weeks 0 days to 27 weeks 6 days of gestation to receive erythropoietin or placebo within 24 hours after birth. Erythropoietin was administered intravenously at a dose of 1000 U per kilogram of body weight every 48 hours for a total of six doses, followed by a maintenance dose of 400 U per kilogram three times per week by subcutaneous injection through 32 completed weeks of postmenstrual age. Placebo was administered as intravenous saline followed by sham injections. The primary outcome was death or severe neurodevelopmental impairment at 22 to 26 months of postmenstrual age. Severe neurodevelopmental impairment was defined as severe cerebral palsy or a composite motor or composite cognitive score of less than 70 (which corresponds to 2 SD below the mean, with higher scores indicating better performance) on the Bayley Scales of Infant and Toddler Development, third edition. RESULTS: A total of 741 infants were included in the per-protocol efficacy analysis: 376 received erythropoietin and 365 received placebo. There was no significant difference between the erythropoietin group and the placebo group in the incidence of death or severe neurodevelopmental impairment at 2 years of age (97 children [26%] vs. 94 children [26%]; relative risk, 1.03; 95% confidence interval, 0.81 to 1.32; P = 0.80). There were no significant differences between the groups in the rates of retinopathy of prematurity, intracranial hemorrhage, sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, or death or in the frequency of serious adverse events. CONCLUSIONS: High-dose erythropoietin treatment administered to extremely preterm infants from 24 hours after birth through 32 weeks of postmenstrual age did not result in a lower risk of severe neurodevelopmental impairment or death at 2 years of age. (Funded by the National Institute of Neurological Disorders and Stroke; PENUT ClinicalTrials.gov number, NCT01378273.).


Asunto(s)
Eritropoyetina/administración & dosificación , Recien Nacido Extremadamente Prematuro , Enfermedades del Prematuro/prevención & control , Trastornos del Neurodesarrollo/prevención & control , Encéfalo/diagnóstico por imagen , Preescolar , Método Doble Ciego , Eritropoyetina/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recién Nacido , Enfermedades del Prematuro/mortalidad , Masculino , Trastornos del Neurodesarrollo/epidemiología , Ultrasonografía
2.
Am J Physiol Endocrinol Metab ; 307(7): E580-8, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25117409

RESUMEN

Recurrent exposure to hypoglycemia can impair the normal counterregulatory hormonal responses that guard against hypoglycemia, leading to hypoglycemia unawareness. This pathological condition known as hypoglycemia-associated autonomic failure (HAAF) is the main adverse consequence that prevents individuals with type 1 diabetes mellitus from attaining the long-term health benefits of tight glycemic control. The underlying molecular mechanisms responsible for the progressive loss of the epinephrine response to subsequent bouts of hypoglycemia, a hallmark sign of HAAF, are largely unknown. Normally, hypoglycemia triggers both the release and biosynthesis of epinephrine through activation of nicotinic acetylcholine receptors (nAChR) on the adrenal glands. We hypothesize that excessive cholinergic stimulation may contribute to impaired counterregulation. Here, we tested whether administration of the nAChR partial agonist cytisine to reduce postganglionic synaptic activity can preserve the counterregulatory hormone responses in an animal model of HAAF. Compared with nicotine, cytisine has limited efficacy to activate nAChRs and stimulate epinephrine release and synthesis. We evaluated adrenal catecholamine production and secretion in nondiabetic rats subjected to two daily episodes of hypoglycemia for 3 days, followed by a hyperinsulinemic hypoglycemic clamp on day 4. Recurrent hypoglycemia decreased epinephrine responses, and this was associated with suppressed TH mRNA induction (a measure of adrenal catecholamine synthetic capacity). Treatment with cytisine improved glucagon responses as well as epinephrine release and production in recurrently hypoglycemic animals. These data suggest that pharmacological manipulation of ganglionic nAChRs may be promising as a translational adjunctive therapy to avoid HAAF in type 1 diabetes mellitus.


Asunto(s)
Glándulas Suprarrenales/efectos de los fármacos , Alcaloides/farmacología , Sistema Nervioso Autónomo/efectos de los fármacos , Glucemia/efectos de los fármacos , Epinefrina/metabolismo , Hipoglucemia/metabolismo , Antagonistas Nicotínicos/farmacología , Receptores Nicotínicos , Tirosina 3-Monooxigenasa/efectos de los fármacos , Glándulas Suprarrenales/metabolismo , Animales , Sistema Nervioso Autónomo/metabolismo , Azocinas/farmacología , Glucemia/metabolismo , Modelos Animales de Enfermedad , Epinefrina/biosíntesis , Perfilación de la Expresión Génica , Técnica de Clampeo de la Glucosa , Masculino , Quinolizinas/farmacología , ARN Mensajero , Ratas , Ratas Sprague-Dawley , Recurrencia , Tirosina 3-Monooxigenasa/genética , Tirosina 3-Monooxigenasa/metabolismo
3.
Pediatr Blood Cancer ; 59(2): 315-7, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22315234

RESUMEN

Hemophagocytic lymphohistiocytosis (HLH) is a systemic disease resulting from the excessive release of inflammatory cytokines by macrophages under prolonged antigenic stimulation. If untreated, it leads to multiorgan failure and death. Necrotizing enterocolitis (NEC) has not previously been associated with HLH. Here we report four preterm infants who were diagnosed with HLH associated with NEC. Two patients received chemotherapy and one survived. The other two infants succumbed to multiorgan failure. These results suggest that NEC may be a common clinical manifestation of HLH in premature neonates.


Asunto(s)
Enterocolitis Necrotizante/diagnóstico , Enfermedades del Prematuro/diagnóstico , Linfohistiocitosis Hemofagocítica/diagnóstico , Insuficiencia Multiorgánica/diagnóstico , Enterocolitis Necrotizante/etiología , Enterocolitis Necrotizante/terapia , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/terapia , Linfohistiocitosis Hemofagocítica/complicaciones , Linfohistiocitosis Hemofagocítica/terapia , Masculino , Insuficiencia Multiorgánica/etiología , Insuficiencia Multiorgánica/terapia , Pronóstico
4.
Brain ; 133(Pt 8): 2264-80, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20488889

RESUMEN

Intraventricular haemorrhage is a major complication of prematurity that results in neurological dysfunctions, including cerebral palsy and cognitive deficits. No therapeutic options are currently available to limit the catastrophic brain damage initiated by the development of intraventricular haemorrhage. As intraventricular haemorrhage leads to an inflammatory response, we asked whether cyclooxygenase-2, its derivative prostaglandin E2, prostanoid receptors and pro-inflammatory cytokines were elevated in intraventricular haemorrhage; whether their suppression would confer neuroprotection; and determined how cyclooxygenase-2 and cytokines were mechanistically-linked. To this end, we used our rabbit model of intraventricular haemorrhage where premature pups, delivered by Caesarian section, were treated with intraperitoneal glycerol at 2 h of age to induce haemorrhage. Intraventricular haemorrhage was diagnosed by head ultrasound at 6 h of age. The pups with intraventricular haemorrhage were treated with inhibitors of cyclooxygenase-2, prostanoid receptor-1 or tumour necrosis factor-α; and cell-infiltration, cell-death and gliosis were compared between treated-pups and vehicle-treated controls during the first 3 days of life. Neurobehavioural performance, myelination and gliosis were assessed in pups treated with cyclooxygenase-2 inhibitor compared to controls at Day 14. We found that both protein and messenger RNA expression of cyclooxygenase-2, prostaglandin E2, prostanoid receptor-1, tumour necrosis factor-α and interleukin-1ß were consistently higher in the forebrain of pups with intraventricular haemorrhage relative to pups without intraventricular haemorrhage. However, cyclooxygenase-1 and prostanoid receptor 2-4 levels were comparable in pups with and without intraventricular haemorrhage. Cyclooxygenase-2, prostanoid receptor-1 or tumour necrosis factor-α inhibition reduced inflammatory cell infiltration, apoptosis, neuronal degeneration and gliosis around the ventricles of pups with intraventricular haemorrhage. Importantly, cyclooxygenase-2 inhibition alleviated neurological impairment, improved myelination and reduced gliosis at 2 weeks of age. Cyclooxygenase-2 or prostanoid receptor-1 inhibition reduced tumour necrosis factor-α level, but not interleukin-1ß. Conversely, tumour necrosis factor-α antagonism did not affect cyclooxygenase-2 expression. Hence, prostanoid receptor-1 and tumour necrosis factor-α are downstream to cyclooxygenase-2 in the inflammatory cascade induced by intraventricular haemorrhage, and cyclooxygenase-2-inhibition or suppression of downstream molecules--prostanoid receptor-1 or tumour necrosis factor-α--might be a viable neuroprotective strategy for minimizing brain damage in premature infants with intraventricular haemorrhage.


Asunto(s)
Inhibidores de la Ciclooxigenasa 2/farmacología , Hemorragias Intracraneales/tratamiento farmacológico , Fármacos Neuroprotectores/farmacología , Receptores de Prostaglandina E/antagonistas & inhibidores , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Animales , Animales Recién Nacidos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/patología , Caspasas/metabolismo , Muerte Celular/efectos de los fármacos , Ventrículos Cerebrales , Ciclooxigenasa 1/metabolismo , Ciclooxigenasa 2/metabolismo , Dinoprostona/metabolismo , Modelos Animales de Enfermedad , Gliosis/tratamiento farmacológico , Gliosis/metabolismo , Gliosis/patología , Interleucina-1beta/metabolismo , Hemorragias Intracraneales/metabolismo , Hemorragias Intracraneales/patología , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/metabolismo , Conejos , Receptores de Prostaglandina E/metabolismo , Subtipo EP1 de Receptores de Prostaglandina E , Factor de Necrosis Tumoral alfa/metabolismo
5.
J Perinat Med ; 39(4): 471-5, 2011 07.
Artículo en Inglés | MEDLINE | ID: mdl-21501101

RESUMEN

We investigated the stability of thyroid hormones during a mode of continuous drug infusion via polypropylene tubing using the same conditions that would be applied to treating patients in a hospital setting. The diluted thyroid hormones were prepared using aseptic technique, stored at 2-8°C (36-46°F) and tested within 24 h of preparation for stability and percent recovery from within plastic tubing. Experiments were done in duplicate with triplicate sets of readings for each assay point. Only T(4) prepared with 5% dextrose water (D5W) containing 1 mg/mL albumin remained constant, stable, predictable and accurate over time under various conditions. Other methods of preparation lost drug by adhering to the plastic containers and tubing by as much as 40% of starting concentration. T(3) recovery in the presence of 1 mg/mL of albumin was 107±2% (mean±standard error of the mean) of anticipated drug concentrations. We conclude from this series of experiments that to maintain an accurate and stable dosing of patients receiving intravenous thyroid hormones, 1 mg/mL of albumin must be added to the infusate to prevent lost on the plastic intravenous tubing.


Asunto(s)
Hormonas Tiroideas/administración & dosificación , Albúminas/administración & dosificación , Animales , Estabilidad de Medicamentos , Humanos , Técnicas In Vitro , Infusiones Intravenosas/instrumentación , Polipropilenos , Soluciones , Hormonas Tiroideas/química , Tiroxina/administración & dosificación , Tiroxina/química , Triyodotironina/administración & dosificación , Triyodotironina/química
6.
Neurobiol Stress ; 15: 100376, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34401412

RESUMEN

The microbiome co-evolved with their mammalian host over thousands of years. This commensal relationship serves a pivotal role in various metabolic, physiological, and immunological processes. Recently we discovered impaired adrenal catecholamine stress responses in germ-free mice suggesting developmental modification of the reflex arc or absence of an ongoing microbiome signal. To determine whether maturational arrest or an absent bacteria-derived metabolite was the cause, we tested whether depleting gut microbiome in young adult animals could also alter the peripheral stress responses to insulin-induced hypoglycemia. Groups of C57Bl6 male mice were given regular water (control) or a cocktail of non-absorbable broad-spectrum antibiotics (Abx) in the drinking water for two weeks before injection with insulin or saline. Abx mice displayed a profound decrease in microbial diversity and abundance of Bacteroidetes and Firmicutes, plus a markedly enlarged caecum and no detectable by-products of bacterial fermentation (sp. short chain fatty acids, SCFA). Tonic and stress-induced epinephrine levels were attenuated. Recolonization (Abx + R) restored bacterial diversity, but not the sympathoadrenal system responsiveness or caecal acetate, propionate and butyrate levels. In contrast, corticosterone (HPA) and glucagon (parasympathetic) resting values and responses to hypoglycemia remained similar across all conditions. Oral supplementation with SCFA improved epinephrine responses to hypoglycaemia. Whole genome shotgun sequence profiling of fecal samples from control, Abx and Abx + R cohorts identified nine microbes (SCFA producers) absent from both Abx and Abx + R groups. These results implicate gut microbiome depletion plus its attendant reduction in SCFA signalling in adversely affecting the release of epinephrine in response to hypoglycemia. We speculate that regardless of postnatal age, a mutable microbiome messaging system exists throughout life. Unravelling these mechanisms could lead to new therapeutic possibilities through controlled manipulation of the gut microbiota and its ability to alter systemic neurotransmitter responsiveness.

7.
JAMA Pediatr ; 174(10): 933-943, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32804205

RESUMEN

Importance: Extremely preterm infants are among the populations receiving the highest levels of transfusions. Erythropoietin has not been recommended for premature infants because most studies have not demonstrated a decrease in donor exposure. Objectives: To determine whether high-dose erythropoietin given within 24 hours of birth through postmenstrual age of 32 completed weeks will decrease the need for blood transfusions. Design, Setting, and Participants: The Preterm Erythropoietin Neuroprotection Trial (PENUT) is a randomized, double-masked clinical trial with participants enrolled at 19 sites consisting of 30 neonatal intensive care units across the United States. Participants were born at a gestational age of 24 weeks (0-6 days) to 27 weeks (6-7 days). Exclusion criteria included conditions known to affect neurodevelopmental outcomes. Of 3266 patients screened, 2325 were excluded, and 941 were enrolled and randomized to erythropoietin (n = 477) or placebo (n = 464). Data were collected from December 12, 2013, to February 25, 2019, and analyzed from March 1 to June 15, 2019. Interventions: In this post hoc analysis, erythropoietin, 1000 U/kg, or placebo was given every 48 hours for 6 doses, followed by 400 U/kg or sham injections 3 times a week through postmenstrual age of 32 weeks. Main Outcomes and Measures: Need for transfusion, transfusion numbers and volume, number of donor exposures, and lowest daily hematocrit level are presented herein. Results: A total of 936 patients (488 male [52.1%]) were included in the analysis, with a mean (SD) gestational age of 25.6 (1.2) weeks and mean (SD) birth weight of 799 (189) g. Erythropoietin treatment (vs placebo) decreased the number of transfusions (unadjusted mean [SD], 3.5 [4.0] vs 5.2 [4.4]), with a relative rate (RR) of 0.66 (95% CI, 0.59-0.75); the cumulative transfused volume (mean [SD], 47.6 [60.4] vs 76.3 [68.2] mL), with a mean difference of -25.7 (95% CI, 18.1-33.3) mL; and donor exposure (mean [SD], 1.6 [1.7] vs 2.4 [2.0]), with an RR of 0.67 (95% CI, 0.58-0.77). Despite fewer transfusions, erythropoietin-treated infants tended to have higher hematocrit levels than placebo-treated infants, most noticeable at gestational week 33 in infants with a gestational age of 27 weeks (mean [SD] hematocrit level in erythropoietin-treated vs placebo-treated cohorts, 36.9% [5.5%] vs 30.4% [4.6%] (P < .001). Of 936 infants, 160 (17.1%) remained transfusion free at the end of 12 postnatal weeks, including 43 in the placebo group and 117 in the erythropoietin group (P < .001). Conclusions and Relevance: These findings suggest that high-dose erythropoietin as used in the PENUT protocol was effective in reducing transfusion needs in this population of extremely preterm infants. Trial Registration: ClinicalTrials.gov Identifier: NCT01378273.


Asunto(s)
Transfusión Sanguínea/tendencias , Eritropoyetina/administración & dosificación , Recién Nacido de Bajo Peso , Enfermedades del Prematuro/terapia , Adulto , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Edad Gestacional , Humanos , Recién Nacido , Masculino
8.
Stroke ; 40(6): 2191-8, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19372442

RESUMEN

BACKGROUND AND PURPOSE: Germinal matrix hemorrhage-intraventricular hemorrhage is the most common neurological problem of premature infants. Despite this, mechanisms of brain injury from intraventricular hemorrhage are elusive. We hypothesized that germinal matrix hemorrhage-intraventricular hemorrhage, by induction of NAD(P)H oxidases, might cause oxidative/nitrosative stress contributing to brain injuries and that NAD(P)H oxidase inhibition could offer neuroprotection. METHODS: To test this hypothesis, we exploited our rabbit pup model of glycerol-induced germinal matrix hemorrhage-intraventricular hemorrhage. We delivered rabbit pups prematurely (E29) by cesarean section and administered intraperitoneal glycerol at 2 hours postnatal age. Free-radical adducts, including nitrotyrosine, 4-hyroxynonenal, and 8-hydroxy-deoxyguanosine as well as O(2)(.-) and H(2)O(2) levels were measured in the forebrain. To determine the source of free-radical generation, we used inhibitors for NAD(P)H oxidase (apocynin), xanthine oxidase (allopurinol), cyclo-oxygenase-2 (indomethacin), or nitric oxide synthases (L-NAME). Intraventricular hemorrhage pups were treated with apocynin and cell death was compared between apocynin-treated and vehicle-treated pups. RESULTS: Nitrotyrosine, 4-hyroxynonenal, and 8-hydroxy-deoxyguanosine levels were higher in pups with intraventricular hemorrhage than controls. Likewise, O(2)(.-) and H(2)O(2) levels were significantly greater in both the periventricular area and cerebral cortex of pups with intraventricular hemorrhage than controls. In pups with intraventricular hemorrhage, reactive oxygen species production was more in the periventricular area than in the cortex. Apocynin, but not allopurinol, indomethacin, or nitric oxide synthases, inhibited reactive oxygen species generation. Importantly, apocynin reduced cell death in pups with intraventricular hemorrhage. CONCLUSIONS: Activation of NAD(P)H oxidase was the predominant mechanism of free-radical generation in pups with intraventricular hemorrhage. NAD(P)H oxidase inhibition by apocynin might suppress reactive oxygen species production and confer neuroprotection in premature infants with intraventricular hemorrhage.


Asunto(s)
Hemorragia Cerebral/metabolismo , Inhibidores Enzimáticos/farmacología , NADPH Oxidasas/antagonistas & inhibidores , NADPH Oxidasas/metabolismo , Fármacos Neuroprotectores , Estrés Oxidativo/fisiología , Especies de Nitrógeno Reactivo/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Acetofenonas/farmacología , Acridinas , Animales , Western Blotting , Hemorragia Cerebral/diagnóstico por imagen , Hemorragia Cerebral/enzimología , Ventrículos Cerebrales/patología , Inducción Enzimática/efectos de los fármacos , Etidio , Colorantes Fluorescentes , Peróxido de Hidrógeno/farmacología , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Luminiscencia , NADPH Oxidasas/genética , Conejos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ultrasonografía
10.
Pediatr Infect Dis J ; 28(3): 210-4, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19209088

RESUMEN

OBJECTIVE: We describe the first outbreak of multiple drug-resistant Acinetobacter baumannii (MDR-Ab) in a neonatal intensive care unit in the United States. DESIGN/METHODS: MDR-Ab was identified in the blood of a 24-week gestation, 7-day-old extremely low birth weight neonate. Multiple samplings of surveillance surface cultures were performed on exposed and nonexposed neonates. Enhanced infection control measures were implemented. Pulsed-field gel electrophoresis was performed to determine the genetic relatedness of the MDR-Ab isolates. Medical records were reviewed for all exposed patients. RESULTS: MDR-Ab was recovered from 6 additional neonates. Of these 7 MDR-Ab (index + 6) neonates, 4 died, 3 of whom had positive blood cultures. All affected neonates were born between 23 to 26 weeks gestational age, and were <7 days postnatal age and <750 g (430-720) at the time of exposure. All were housed within the same room as the index case. None of the other 5 exposed neonates older than postnatal day 7 or weighing >750 g at birth were affected. No additional cases occurred outside the original room. Pulsed-field gel electrophoresis was consistent with a clonal origin, identical to MDR-Ab recovered from the referring hospital. CONCLUSIONS: This MDR-Ab outbreak was rapidly controlled with enhanced infection control measures and was novel in that it affected only <750 g neonates, at < or =26 weeks gestational age, and < or =7 days postnatal age at the time of exposure, suggesting that invasive Ab has a special affinity for damaged or nonkeratinized immature skin in developmentally immature immunologic hosts.


Asunto(s)
Infecciones por Acinetobacter/epidemiología , Acinetobacter baumannii/aislamiento & purificación , Brotes de Enfermedades , Farmacorresistencia Bacteriana Múltiple , Recien Nacido con Peso al Nacer Extremadamente Bajo , Enfermedades del Prematuro/epidemiología , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/clasificación , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Adulto , Electroforesis en Gel de Campo Pulsado , Femenino , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/microbiología , Enfermedades del Prematuro/prevención & control , Unidades de Cuidado Intensivo Neonatal , Masculino
12.
Am J Perinatol ; 26(5): 361-4, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19085679

RESUMEN

Parainfluenza virus (PIV) causes > 30% of all acute respiratory infections in infants and children and is second only to respiratory syncytial virus as a cause of lower respiratory tract infection. However in the neonatal intensive care unit (NICU), PIV outbreaks are highly uncommon. This case report describes an outbreak of 3 cases of PIV type 3 in a regional NICU.


Asunto(s)
Brotes de Enfermedades , Unidades de Cuidado Intensivo Neonatal , Virus de la Parainfluenza 3 Humana , Infecciones por Respirovirus/epidemiología , Brotes de Enfermedades/prevención & control , Resultado Fatal , Femenino , Humanos , Lactante , Recién Nacido , Control de Infecciones/métodos , Masculino , New York , Infecciones por Respirovirus/diagnóstico , Infecciones por Respirovirus/terapia , Resultado del Tratamiento
13.
Stroke ; 39(12): 3378-88, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18845808

RESUMEN

BACKGROUND AND PURPOSE: Germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) is the most common neurological problem of premature infants and has enormous financial and social impact. Despite this, there is no standardized animal model of IVH depicting acute brain injuries. METHODS: We delivered rabbit-pups prematurely at 29-day gestation by C-section, administered intraperitoneal glycerol to the pups at 3-hour postnatal age to induce IVH, and evaluated the brain for evidence of injuries. RESULTS: About 80% of glycerol-treated pups developed gross IVH. We found greater neutrophil and microglia infiltration around the ventricles (periventricular zone) in pups with IVH than in controls. We noted more apoptosis and neuronal degeneration in the periventricular zone than in the neocortex in pups with IVH, but not in controls. There was evidence of axonal damage revealed by beta-amyloid precursor protein and neurofilament immunolabeling. Neurobehavioral testing showed that pups with IVH were more wobbly with lesser capability to walk on inclination than pups without IVH. There was no evidence of acute systemic toxicity in the glycerol-treated pups. An evaluation of autopsy materials from premature infants revealed similar evidence of apoptosis and cellular infiltration in the periventricular zone in cases with IVH, but not in cases without IVH-suggesting clinical relevance of the model. CONCLUSIONS: The study provides an instructive animal model of IVH with evidence of acute brain injuries that can be used to evaluate strategies in prevention of IVH and acute posthemorrhagic complications.


Asunto(s)
Hemorragia Cerebral/inducido químicamente , Ventrículos Cerebrales/patología , Modelos Animales de Enfermedad , Animales , Animales Recién Nacidos , Apoptosis , Conducta Animal , Encéfalo/patología , Hemorragia Cerebral/diagnóstico por imagen , Hemorragia Cerebral/patología , Hemorragia Cerebral/psicología , Femenino , Edad Gestacional , Glicerol/administración & dosificación , Glicerol/toxicidad , Humanos , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/patología , Inyecciones Intraperitoneales , Microglía/patología , Degeneración Nerviosa/inducido químicamente , Degeneración Nerviosa/etiología , Neutrófilos/patología , Embarazo , Nacimiento Prematuro , Conejos , Método Simple Ciego , Ultrasonografía
14.
J Neurosci Res ; 86(7): 1482-500, 2008 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-18214989

RESUMEN

Germinal matrix is selectively vulnerable to hemorrhage in premature infants, and use of prenatal betamethasone is associated with a lower occurrence of germinal matrix hemorrhage. Because the major components of extracellular matrix of the cerebral vasculature-laminin, fibronectin, collagen IV, and perlecan-provide structural stability to blood vessels, we examined whether the expression of these molecules was decreased in the germinal matrix and affected by betamethasone. In both human fetuses and premature infants, fibronectin was significantly lower in the germinal matrix than in the cortical mantle or white matter anlagen. Conversely, laminin alpha1 gene expression was greater in the human germinal matrix compared with the cortical mantle or white matter. Expression of alpha1- and alpha2(IV) collagen chains increased with advancing gestational age. Low-dose prenatal betamethasone treatment enhanced fibronectin level by 1.5-2-fold whereas a high dose reduced fibronectin expression by 2-fold in rabbit pups. Because fibronectin provides structural stability to the blood vessels, its reduced expression in the germinal matrix may contribute to the fragility of germinal matrix vasculature and the propensity to hemorrhage in premature neonates.


Asunto(s)
Antiinflamatorios/farmacología , Betametasona/farmacología , Corteza Cerebral , Ventrículos Cerebrales , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Proteoglicanos de Heparán Sulfato/metabolismo , Glicoproteínas de Membrana/metabolismo , Neuroglía/metabolismo , Análisis de Varianza , Animales , Corteza Cerebral/citología , Corteza Cerebral/embriología , Corteza Cerebral/metabolismo , Ventrículos Cerebrales/citología , Ventrículos Cerebrales/embriología , Ventrículos Cerebrales/metabolismo , Colágeno Tipo IV/metabolismo , Femenino , Feto , Fibronectinas/metabolismo , Edad Gestacional , Humanos , Recién Nacido , Laminina/metabolismo , Masculino , Pericitos/citología , Pericitos/metabolismo , Embarazo , Conejos
15.
Brain Res Dev Brain Res ; 160(1): 53-62, 2005 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-16165221

RESUMEN

Butyrate is a diet-derived, gut fermentation product with an array of effects on cultured mammalian cells including inhibition of proliferation, induction of differentiation and regulation of gene expression. We showed that physiological concentrations of butyrate can regulate transcription of tyrosine hydroxylase (TH) and preproenkephalin (ppEnk) gene in PC12 cells. In promoter deletion studies, electrophoretic mobility shift assays and by site-directed mutagenesis, we identified a novel butyrate response element (BRE) in the 5' upstream region of the rat TH gene, homologous to the previously mapped motif in the ppEnk promoter. No such enhancers were found in DBH or PNMT promoters, and both catecholamine system-related gene promoters were unaffected by butyrate. The BRE motif interacts with nuclear proteins in a sequence-specific manner, shows binding potentiation in butyrate-differentiated PC12 cells and bound protein(s) are competed away with TH-CRE oligonucleotides or by the addition of CREB-specific antibodies, suggesting involvement of CREB or CREB-related transcription factors. Moreover, single point mutation in the distal BRE abolished binding of transcription factors and reduced the response to butyrate in transient transfection studies. The canonical CRE motif of the TH promoter was also found necessary for transcriptional activation of the TH gene by butyrate. Our data identified a novel functional element in the promoter of both the TH and ppEnk genes mediating transcriptional responses to butyrate. Dietary butyrate may have an extended role in the control of catecholamine and endogenous opioid production at the level of TH and ppEnk gene transcription neuronal plasticity, cardiovascular functions, stress adaptation and behavior.


Asunto(s)
Butiratos/metabolismo , Catecolaminas/biosíntesis , Regulación del Desarrollo de la Expresión Génica/genética , Neuronas/enzimología , Regiones Promotoras Genéticas/genética , Tirosina 3-Monooxigenasa/genética , Médula Suprarrenal/efectos de los fármacos , Médula Suprarrenal/enzimología , Médula Suprarrenal/crecimiento & desarrollo , Animales , Butiratos/farmacología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteínas de Unión al ADN/efectos de los fármacos , Proteínas de Unión al ADN/genética , Encefalinas/biosíntesis , Encefalinas/genética , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Mutagénesis Sitio-Dirigida , Neuronas/efectos de los fármacos , Células PC12 , Regiones Promotoras Genéticas/efectos de los fármacos , Precursores de Proteínas/genética , Ratas , Elementos de Respuesta/efectos de los fármacos , Elementos de Respuesta/genética , Activación Transcripcional/efectos de los fármacos , Activación Transcripcional/genética
16.
Exp Neurol ; 263: 200-13, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25263581

RESUMEN

Postnatal glucocorticoids (GCs) are widely used in the prevention of chronic lung disease in premature infants. Their pharmacologic use is associated with neurodevelopmental delay and cerebral palsy. However, the effect of GC dose and preparation (dexamethasone versus betamethasone) on short and long-term neurological outcomes remains undetermined, and the mechanisms of GC-induced brain injury are unclear. We hypothesized that postnatal GC would induce hypomyelination and motor impairment in a preparation- and dose-specific manner, and that GC receptor (GR) inhibition might restore myelination and neurological function in GC-treated animals. Additionally, GC-induced hypomyelination and neurological deficit might be transient. To test our hypotheses, we treated prematurely delivered rabbit pups with high (0.5mg/kg/day) or low (0.2mg/kg/day) doses of dexamethasone or betamethasone. Myelin basic protein (MBP), oligodendrocyte proliferation and maturation, astrocytes, transcriptomic profile, and neurobehavioral functions were evaluated. We found that high-dose GC treatment, but not low-dose, reduced MBP expression and impaired motor function at postnatal day 14. High-dose dexamethasone induced astrogliosis, betamethasone did not. Mifepristone, a GR antagonist, reversed dexamethasone-induced myelination, but not astrogliosis. Both GCs inhibited oligodendrocyte proliferation and maturation. Moreover, high-dose dexamethasone altered genes associated with myelination, cell-cycle, GR, and mitogen-activated protein kinase. Importantly, GC-induced hypomyelination, gliosis, and motor-deficit, observed at day 14, completely recovered by day 21. Hence, high-dose, but not low-dose, postnatal GC causes reversible reductions in myelination and motor functions. GC treatment induces hypomyelination by GR-dependent genomic mechanisms, but astrogliosis by non-genomic mechanisms. GC-induced motor impairment and neurodevelopmental delay might be transient and recover spontaneously in premature infants.


Asunto(s)
Encéfalo/efectos de los fármacos , Glucocorticoides/efectos adversos , Vaina de Mielina/efectos de los fármacos , Animales , Animales Recién Nacidos , Betametasona/administración & dosificación , Betametasona/efectos adversos , Western Blotting , Encéfalo/patología , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Gliosis/inducido químicamente , Gliosis/patología , Glucocorticoides/administración & dosificación , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Vaina de Mielina/patología , Conejos , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Glucocorticoides/metabolismo
17.
Pediatr Infect Dis J ; 23(4): 318-22, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-15071285

RESUMEN

BACKGROUND: Respiratory syncytial virus (RSV) is the most common respiratory pathogen in infancy and childhood. OBJECTIVE: To compare the compliance and biologic efficacy of a home health care agency dosing-compliance program to treatment provided in a physician's office setting during a single RSV season (November to May). METHODS.: AAP guidelines were used to identify neonates who were eligible for RSV prophylaxis before discharge from a neonatal intensive care unit setting. Parents were asked to choose to receive the recommended treatment for their child either in their pediatrician's office setting or through a sequence of periodic nursing visits to their home. All home health care records were reviewed for demographics, number of doses received and hospitalization rate. Pediatricians office records were surveyed by telephone interview of their office staff and parents. Compliance data were calculated based on actual monthly injections given during the RSV season. RESULTS: We followed prospectively 1446 infants who received palivizumab during a single RSV season (November 1, 2000 through April 30, 2001). Of these infants 67% (969 of 1446) received their monthly injections in the home setting where 98% of the doses were given on schedule. In contrast 477 infants (33%) received their injections in a pediatrician's office (parent's choice) with a compliance of only 89% for completion of all recommended doses (P < 0.001 vs. home setting). There were 9 RSV hospitalizations (0.93%) in the home setting group and 8 RSV hospitalizations (3.57%) in the office setting (P < 0.001). More parents indicated that the in-home prophylaxis program was more convenient than was true for those receiving treatment in the physician's office setting (P < 0.01). CONCLUSIONS: Better compliance with home injections was associated with a decrease in the hospitalization rate for RSV with a higher degree of parental satisfaction.


Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Servicios de Atención de Salud a Domicilio/normas , Visita a Consultorio Médico , Infecciones por Virus Sincitial Respiratorio/tratamiento farmacológico , Infecciones por Virus Sincitial Respiratorio/prevención & control , Anticuerpos Monoclonales Humanizados , Preescolar , Esquema de Medicación , Femenino , Estudios de Seguimiento , Servicios de Atención de Salud a Domicilio/tendencias , Humanos , Lactante , Recién Nacido , Inyecciones Intramusculares , Masculino , Palivizumab , Cooperación del Paciente , Probabilidad , Estudios Prospectivos , Medición de Riesgo , Estadísticas no Paramétricas
18.
J Perinatol ; 22(7): 563-5, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12368973

RESUMEN

We mailed a survey on treatment practices for transient hypothyroxinemia of prematurity (THOP) to 100 randomly selected neonatologists. In the year before the survey, 13 of 62 respondents (21.0%) had treated an average of 4.5 THOP patients with thyroid hormone, and 3 had treated 10 or more patients. Randomized trials assessing the value of thyroid supplementation in THOP are urgently needed.


Asunto(s)
Enfermedades del Prematuro/tratamiento farmacológico , Pautas de la Práctica en Medicina , Hormonas Tiroideas/uso terapéutico , Tiroxina/sangre , Encuestas de Atención de la Salud , Humanos , Recién Nacido , Recien Nacido Prematuro , Perinatología
19.
J Perinatol ; 22(3): 209-13, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-11948383

RESUMEN

OBJECTIVE: Extremely low birth weight (ELBW) infants often acquire catheter-related infections (CRIs) when a percutaneously inserted central catheter (PICC) is used for parenteral nutrition or drug administration. Our objective was to compare the incidence of CRIs after we established a "PICC Maintenance Team" for the proactive management--compared to expectant management--of these lines. STUDY DESIGN: We did a prospective collection and analysis of catheter-related sepsis data over a 15-month period from February 1, 1998 through May 1, 1999. Eligible patients included all neonates weighing <1000 g at birth. RESULTS: There was a significantly decreased incidence of CRIs, to a rate of 7.1%, or 5.1/1000 catheter days (p<0.05). CONCLUSION: "Proactive" management of PICC, significantly reduced the incidence of CRIs. The reduction in infection rate is estimated to save 180 hospitalized patient days/100 very low birth weight neonates, with a concomitant savings in morbidity and medical expense.


Asunto(s)
Cateterismo Venoso Central/métodos , Enfermedades del Prematuro/prevención & control , Recién Nacido de muy Bajo Peso , Sepsis/prevención & control , Humanos , Recién Nacido , Estudios Prospectivos
20.
Thyroid ; 24(7): 1162-9, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24684245

RESUMEN

BACKGROUND: Thyroid hormones are required for normal brain maturation, and neonatal plasma thyroid hormone concentrations are low in infants less than 28 weeks gestation. It is not known whether treatment of such infants with thyroid hormone improves neurodevelopmental outcome. METHODS: At three years corrected age, mental, motor, and neurological development was assessed in infants born at less than 28 weeks gestational age who had participated in a phase 1 trial of differing doses and modes of administration of thyroid hormone. The trial's endpoints were thyroid hormone (thyroxine, T4) and thyotropin plasma concentrations in eight study arms: six treated with T4 [4, 8, and 16 µg/(kg · day)], bolus or continuous], one treated with iodine only, and one treated with placebo. Follow-up at three years was not part of the original study goals. Developmental index scores, rates of cerebral palsy (CP), and rates of adverse outcome (death or moderate to severe delay in development and/or disabling CP) were compared between the eight study groups and between groups combined by dosage level, and between infants with and without T4 supplementation. RESULTS: Of 166 randomized infants, 32 (19%) died in the neonatal period. Of the 134 survivors, follow-up results were available for 89 children (66%). Mental and motor development and rates of cerebral palsy did not differ in any of the comparisons made. CONCLUSION: In this study, no differences in neurodevelopment were found in relation to thyroid hormone treatment, but power was insufficient to detect any but very large differences.


Asunto(s)
Desarrollo Infantil/efectos de los fármacos , Terapia de Reemplazo de Hormonas/métodos , Destreza Motora/efectos de los fármacos , Hormonas Tiroideas/uso terapéutico , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Recien Nacido Extremadamente Prematuro , Masculino , Hormonas Tiroideas/administración & dosificación , Hormonas Tiroideas/sangre
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA