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Autoregulation premature

Gracjana Klein, Anna Stupak, Daria Biernacka, Pawel Wojtkiewicz, Buko Lindner, Satish Raina
The RpoE sigma factor is essential for the viability of Escherichia coli RpoE regulates extracytoplasmic functions including lipopolysaccharide (LPS) translocation and some of its non-stoichiometric modifications. Transcription of the rpoE gene is positively autoregulated by Eσ(E) and by unknown mechanisms that control the expression of its distally located promoter(s). Mapping of 5' ends of rpoE mRNA identified five new transcriptional initiation sites (P1 to P5) located distal to Eσ(E)-regulated promoter...
September 14, 2016: Journal of Biological Chemistry
Christopher J Rhee, Charles D Fraser, Kathleen Kibler, Ronald B Easley, Dean B Andropoulos, Marek Czosnyka, Georgios V Varsos, Peter Smielewski, Craig G Rusin, Ken M Brady, Jeffrey R Kaiser
Our objective was to quantify cerebrovascular autoregulation as a function of gestational age (GA) and across the phases of the cardiac cycle. One hundred eighty-six premature infants, with a GA range of 23-33 weeks, were monitored using umbilical artery catheters and transcranial Doppler insonation of middle cerebral artery flow velocity (FV) for 1-h sessions over the first week of life. Autoregulation was quantified as a moving correlation coefficient between systolic arterial blood pressure (ABP) and systolic FV (Sx); mean ABP and mean FV (Mx); diastolic ABP and diastolic FV (Dx)...
2016: Acta Neurochirurgica. Supplement
Alexander Caicedo, Thomas Alderliesten, Gunnar Naulaers, Petra Lemmers, Frank van Bel, Sabine Van Huffel
We present a new framework for the assessment of cerebral hemodynamics regulation (CHR) in neonates using near-infrared spectroscopy (NIRS). In premature infants, NIRS measurements have been used as surrogate variables for cerebral blood flow (CBF) in the assessment of cerebral autoregulation (CA). However, NIRS measurements only reflect changes in CBF under constant changes in arterial oxygen saturation (SaO2). This condition is unlikely to be met at the bedside in the NICU. Additionally, CA is just one of the different highly coupled mechanisms that regulate brain hemodynamics...
2016: Advances in Experimental Medicine and Biology
Zachary A Vesoulis, Steve M Liao, Shamik B Trivedi, Nathalie El Ters, Amit M Mathur
BACKGROUND: Autoregulatory dysfunction is an important contributor to brain injury in premature infants, particularly intraventricular hemorrhage (IVH). The autoregulatory system acts as a filter that dampens the systemic blood flow to follow a normal cerebral perfusion profile. METHODS: Simultaneous arterial blood pressure and cerebral near-infrared spectroscopy (NIRS) data were collected from infants born before 28 wk estimated gestational age. The resulting data were preprocessed and then divided into nonoverlapping 20-min epochs...
March 2016: Pediatric Research
Eric S Peeples, Edin Mehic, Pierre D Mourad, Sandra E Juul
BACKGROUND: Altered cerebral perfusion from impaired autoregulation may contribute to the morbidity and mortality associated with premature birth. We hypothesized that fast Doppler imaging could provide a reproducible bedside estimation of cerebral perfusion and autoregulation in preterm infants. METHODS: This is a prospective pilot study using fast Doppler ultrasound to assess blood flow velocity in the basal ganglia of 19 subjects born at 26-32 wk gestation...
February 2016: Pediatric Research
Ruth Feldman
Sensitive periods (SP) in behavioral development appeared in the biological sciences during the first decade of the 20th century, and research in animal models beginning in the 1950s provide terminology and evidence for SP effects. This paper proposes a rigorous program for human SP research and argues that the complexity of the human brain and variability of the human ecology necessitate that SP effects must be studied in humans, employ longitudinal designs starting at birth, test mechanism-based hypotheses based on animal studies that manipulate early environments, and utilize high-risk conditions as "natural experiments...
May 2015: Development and Psychopathology
Jenna E Smith, Kristian E Baker
Nonsense-mediated RNA decay (NMD) represents an established quality control checkpoint for gene expression that protects cells from consequences of gene mutations and errors during RNA biogenesis that lead to premature termination during translation. Characterization of NMD-sensitive transcriptomes has revealed, however, that NMD targets not only aberrant transcripts but also a broad array of mRNA isoforms expressed from many endogenous genes. NMD is thus emerging as a master regulator that drives both fine and coarse adjustments in steady-state RNA levels in the cell...
June 2015: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Ramya Rajagopalan, Sébastien Wielgoss, Gerardo Lippert, Gregory J Velicer, Lee Kroos
UNLABELLED: During starvation-induced development of Myxococcus xanthus, thousands of rod-shaped cells form mounds in which they differentiate into spores. The dev locus includes eight genes followed by clustered regularly interspaced short palindromic repeats (CRISPRs), comprising a CRISPR-Cas system (Cas stands for CRISPR associated) typically involved in RNA interference. Mutations in devS or devR of a lab reference strain permit mound formation but impair sporulation. We report that natural isolates of M...
April 2015: Journal of Bacteriology
G V Nikolaeva, E I Sidorenko, M R Guseva, O A Babak
OBJECTIVE: Despite the importance of blood flow regulation (BFR) in cerebral vessels, in particular, during organism development, there is no studies in children in the first weeks of life. We studied biochemical autoregulation of blood flow in infants born at 24-25 weeks of gestation. MATERIAL AND METHODS: Eighteen infants with body mass 763±138 g were included in the study. RESULTS: There was a high frequency of intraventricular hemorrhages (77%, 14 infants), including those of III stage (50%) with ventriculomegalia (9 infants)...
2014: Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova
Nihat Demir, İbrahim Ece, Erdal Peker, Sultan Kaba, Lokman Ustyol, Ragıp Balahoroğlu, Oğuz Tuncer
BACKGROUND: Hemodynamically significant patent ductus arteriosus (hsPDA) leads to injury in tissues/organs by reducing perfusion of organs and causing oxidative stress. The purpose of this study was to evaluate the oxidant/antioxidant status in preterm infants with hsPDA by measuring the total antioxidant capacity and total oxidant status and to assess neuronal damage due to oxidant stress related to hsPDA. MATERIAL AND METHODS: This prospective study included 37 low-birth-weight infants with echocardiographically diagnosed hsPDA treated with oral ibuprofen and a control group of 40 infants without PDA...
2014: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
Fan Fan, Aron M Geurts, Mallikarjuna R Pabbidi, Stanley V Smith, David R Harder, Howard Jacob, Richard J Roman
We recently reported that the myogenic responses of the renal afferent arteriole (Af-Art) and middle cerebral artery (MCA) and autoregulation of renal and cerebral blood flow (RBF and CBF) were impaired in Fawn Hooded hypertensive (FHH) rats and were restored in a FHH.1BN congenic strain in which a small segment of chromosome 1 from the Brown Norway (BN) containing 15 genes including dual-specificity protein phosphatase-5 (Dusp5) were transferred into the FHH genetic background. We identified 4 single nucleotide polymorphisms in the Dusp5 gene in FHH as compared with BN rats, two of which altered CpG sites and another that caused a G155R mutation...
2014: PloS One
Vibeke R Eriksen, Gitte H Hahn, Gorm Greisen
AIM: Hypotension is a common problem in newborn infants and is associated with increased mortality and morbidity. Dopamine is the most commonly used antihypotensive drug therapy, but has never been shown to improve neurological outcomes. This study tested our hypothesis that dopamine affects cerebral autoregulation (CA). METHODS: Near-infrared spectroscopy was used to measure the cerebral oxygenation index in 60 very preterm infants, and mean arterial blood pressure was monitored towards the end of their first day of life...
December 2014: Acta Paediatrica
Renée Lampe, Nikolai Botkin, Varvara Turova, Tobias Blumenstein, Ana Alves-Pinto
Impaired cerebral autoregulation leads to fluctuations in cerebral blood flow, which can be especially dangerous for immature brain of preterm newborns. In this paper, two mathematical models of cerebral autoregulation are discussed. The first one is an enhancement of a vascular model proposed by Piechnik et al. We extend this model by adding a polynomial dependence of the vascular radius on the arterial blood pressure and adjusting the polynomial coefficients to experimental data to gain the autoregulation behavior...
2014: Computational and Mathematical Methods in Medicine
C J Rhee, C D Fraser, K Kibler, R B Easley, D B Andropoulos, M Czosnyka, G V Varsos, P Smielewski, C G Rusin, K M Brady, J R Kaiser
OBJECTIVE: To quantify cerebrovascular autoregulation as a function of gestational age (GA) and across the phases of the cardiac cycle. STUDY DESIGN: The present study is a hypothesis-generating re-analysis of previously published data. Premature infants (n=179) with a GA range of 23 to 33 weeks were monitored with umbilical artery catheters and transcranial Doppler insonation of the middle cerebral artery for 1-h sessions over the first week of life. Autoregulation was quantified by three methods, as a moving correlation coefficient between: (1) systolic arterial blood pressure (ABP) and systolic cerebral blood flow (CBF) velocity (Sx); (2) mean ABP and mean CBF velocity (Mx); and (3) diastolic ABP and diastolic CBF velocity (Dx)...
December 2014: Journal of Perinatology: Official Journal of the California Perinatal Association
Hitesh Soni, Randal K Buddington, Adebowale Adebiyi
AIM: Intravascular pressure-induced vasoconstriction (myogenic constriction) is central to renal blood flow autoregulation. At term, kidney maturation is functionally incomplete. Premature neonates are at risk of kidney dysfunction. However, it is unclear whether renal artery myogenic constriction is altered after preterm birth. Here, we compared renal artery myogenic constriction in full-term and preterm pigs during the first week of life. METHODS: We investigated myogenic constriction in small interlobular arteries isolated from the kidneys of pigs delivered at term and at 91% of term (with and without 96 h of neonatal intensive care)...
January 2015: Journal of Perinatal Medicine
S Mitra, M Czosnyka, P Smielewski, H O'Reilly, K Brady, T Austin
AIM: Near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD) allow non-invasive assessment of cerebral haemodynamics. We assessed cerebrovascular reactivity in preterm infants by investigating the relationship between NIRS- and TCD-derived indices and correlating them with severity of clinical illness. METHODS: We recorded the NIRS-derived cerebral tissue oxygenation index (TOI) and TCD-derived flow velocity (Fv), along with other physiological variables...
September 2014: Acta Paediatrica
Adam J Czynski, Michael H Terry, Douglas D Deming, Gordon G Power, John N Buchholz, Arlin B Blood
Cerebral vessels in the premature newborn brain are well supplied with adrenergic nerves, stemming from the superior cervical ganglia (SCG), but their role in regulation of blood flow remains uncertain. To test this function twelve premature or two-week-old lambs were instrumented with laser Doppler flow probes in the parietal cortices to measure changes in blood flow during changes in systemic blood pressure and electrical stimulation of the SCG. In lambs delivered prematurely at ∼129 days gestation cerebral perfusion and driving pressure demonstrated a direct linear relationship throughout the physiologic range, indicating lack of autoregulation...
2013: PloS One
Krista M Haines, Wei Wang, Christopher R Pierson
BACKGROUND: Cerebellar hemorrhagic injury (CHI) is being recognized more frequently in premature infants. However, much of what we know about CHI neuropathology is from autopsy studies that date back to a prior era of neonatal intensive care. To update and expand our knowledge of CHI we reviewed autopsy materials and medical records of all live-born preterm infants (<37 weeks gestation) autopsied at our institution from 1999-2010 who had destructive hemorrhagic injury to cerebellar parenchyma (n = 19) and compared them to matched non-CHI controls (n = 26)...
2013: Acta Neuropathologica Communications
Elise A Verhagen, Liesbeth A Hummel, Arend F Bos, Elisabeth M W Kooi
OBJECTIVE: Our aim was to explore clinical parameters that might predict the absence of cerebrovascular autoregulation (CAR) assessed by a negative relationship between mean arterial blood pressure (MABP) and fractional tissue oxygen extraction (FTOE) as measured by near-infared spectroscopy (NIRS) in preterm infants. METHODS: We included preterm infants (gestational age (GA) <32 weeks). Within 72 h after birth, we recorded the infants' NIRS parameters and MABP for a 24-h period...
January 2014: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Monika Vishnoi, Jatin Narula, Seram Nganbiton Devi, Hoang-Anh Dao, Oleg A Igoshin, Masaya Fujita
Sporulation initiation in Bacillus subtilis is controlled by the phosphorylated form of the master regulator Spo0A which controls transcription of a multitude of sporulation genes. In this study, we investigated the importance of temporal dynamics of phosphorylated Spo0A (Spo0A∼P) accumulation by rewiring the network controlling its phosphorylation. We showed that simultaneous induction of KinC, a kinase that can directly phosphorylate Spo0A, and Spo0A itself from separately controlled inducible promoters can efficiently trigger sporulation even under nutrient rich conditions...
October 2013: Molecular Microbiology
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